FORM 2 THE PATENT ACT, 1 970 (39 OF 1 970) COMPLETE SPECIFICATION (SEE SECTION 10) "Novel N-Arylalkyl-3-aminoalkoxyindoles, having Serotonin receptor affinity useful as therapeutic agents, process for their preparation and pharmaceutical compositions containing them" Suven Life Sciences Limited, formerly known as Suven Pharmaceuticals Limited, an Indian company of Serene Chambers, Road No. 7, Banjara Hills, Hyderabad - 500 034, Andhra Pradesh, India The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed: Novel N-Arylalkyl-3-aminoalkoxyindoles, having Serotonin receptor affinity useful as therapeutic agents, process for their preparation and pharmaceutical compositions containing them. Field of Invention: The present invention includes compounds described by general formula (I), its stereoisomers, its radioisotopes, its geometric forms, its N-oxides, its polymorphs, its pharmaceutical^ acceptable salts, its pharmaceutical^ acceptable solvates, its useful bioactive metabolites and any suitable combination of the above. R4 ** Re General Formula (I) Further the present invention also includes the processes for preparing such compounds of the general formula (I), its stereoisomers, its radioisotopes, its geometric forms, its N-oxides, its polymorphs, its pharmaceutical^ acceptable salts, its pharmaceutical^ acceptable solvates, its useful bioactive metabolites and also includes any suitable combination of the above. The invention also describes various methods of administering these compounds of general formula (I), i.e. pharmaceutical^ acceptable dosage forms compositions and the use of such compounds and compositions in either therapy or diagnosis. The compounds of the general formula (I) of this invention are 5-HT (Serotonin) ligands e.g. agonists or antagonists. The compounds of the general formula (I) of this invention, by the virtue of its chemical characteristic, could either independently or simultaneously modulate the melatonin receptor i.e. either these compounds are melatonergic ligands e.g. agonists or antagonists, or they interact with both 5-HT and/or as Melatonin receptors. Thus, compounds of general formula (I) of this invention are useful for treating diseases wherein activity of either 5-HT (Serotonin) and/or Melatonin is modulated to obtain the desired therapeutic effect Specifically, the compounds of this invention are useful in the treatment and / or prophylaxis of conditions such as psychosis, paraphrenia, psychotic depression, mania, schizophrenia, schizophreniform disorders, anxiety, migraine headache, depression, drug addiction, convulsive disorders, personality disorders, hypertension, autism, post-traumatic stress syndrome, alcoholism, panic attacks, obsessive-compulsive disorders, chronobiological abnormalities, circadian rhythms, anxiolytic, osteoporosis, ischemic stroke, lower the risk of SIDS in young infants with low endogenous melatonin levels, reproduction, glaucoma and sleep disorders. Hence, the compounds of general formula (I) of this invention could also be useful in treating the psychotic, affective, vegetative and psychomotor symptoms of schizophrenia and the extrapyramidal motor side effects of other antipsychotic drugs; neurodegenerative disorders like Alzheimer's disease, Parkinson's and Huntington's chorea and chemotherapy-induced vomiting; and in modulation of eating behavior and thus are useful in reducing the morbidity and mortality associated with excess weight. Background of the Invention Many diseases of the central nervous system are influenced by the adrenergic, the dopaminergic and the serotoninergic neurotransmitter systems. Serotonin has been implicated in numerous diseases and conditions, which originate from central nervous system. The list includes diseases and conditions related to sleeping, eating, perceiving pain, controlling body temperature, controlling blood pressure, depression, anxiety, schizophrenia and other bodily states. (References: Fuller, R. W., Drugs Acting on Serotoninergic Neuronal Systems, in "Biology of Serotoninergic Transmission", ed. by Osborne N. N„ J Wiley & Sons Inc. (1982), 221-247; Boullin D. J., et. al., in "Serotonin in Mental Abnormalities", International Association for The Scientific Study of Mental Deficiency, Wiley, Checester, 1978, pp. 1-340; Barchas J. et. al., in "Serotonin and Behavior", Academic Press, NY (1973)). Serotonin also plays an important role in the peripheral systems, such as the gastrointestinal system, where it has been found to mediate a variety of contractile, secretory and electrophysiologic effects: Due to the broad distribution of serotonin within the body, there is a lot of interest and use, in the drugs that affect serotoninergic systems. Particularly, preferred are the compounds which have receptor-specific agonism and/or antagonism for the treatment of a wide range of disorders, including anxiety, depression, hypertension, migraine, obesity, compulsive disorders, schizophrenia, autism, certain other neurodegenerative disorders like Alzheimer, Parkinson, Huntington's chorea and chemotherapy-induced vomiting (References: Gershon M. D. et. al., 5-Hydroxytryptamine and enteric neurons. In: The Peripheral Actions of 5- 3 Hydroxytryptamine, edited by J. R. Fozard. New York: Oxford, 1989, p. 247-273; Saxena P. R. et. a!., Journal of Cardiovascular Pharmacology (1990), supplement 15, 17-34). The major classes of serotonin receptors (S-HTw) contain fourteen to eighteen separate receptors that have been formally classified (References: Glennon et al, Neuroscience and Behavioral Reviews (1990), 14, 35; and Hoyer D. et al, Pharmacol. Rev. (1994), 46, 157-203). Recently discovered information regarding sub-type identity, distribution, structure and function suggests that it is possible to identify novel, sub-type specific agents having improved therapeutic profiles with lesser side effects. The 5-HT6 receptor was identified in 1993 (References: Monsma et al, Mol. Pharmacol. (1993), 43, 320-327; and Ruat M. et al, Biochem. Biophys. Res. Com. (1993), 193, 269-276). Several antidepressants and atypical antipsychotics bind to the 5-HT6 receptor with high affinity and this binding may be a factor in their profile of activities (References: Roth et al, J. Pharm. Exp. Therapeut. (1994), 268, 1403-1410; Sleight et al, Exp. Opin. Ther. Patents (1998), 8, 1217-1224; Bourson et al, Brit. J. Pharmacol. (1998), 125, 1562-1566; Boess etal, Mol. Pharmacol., 1998, 54, 577-583; Sleight etal, Brit. J. Pharmacol. (1998), 124, 556-562). In addition, 5-HT6 receptor has been linked to generalized stress and anxiety states (Reference: Yoshioka et al, Life Sciences (1998), 17/18,1473-1477). Together these studies and observations suggest that the compound, which antagonizes 5-HT6 receptors, will be useful in treating various disorders of the central nervous system. There is very strong evidence that Melatonin is important for the regulation of a variety of neural and endocrine functions, especially those that exhibit circadian and circannual rhythmicity. Great interest therefore lies in the possibility of making available to the clinician melatonin analogues that are metabolically more stable and have an agonist or antagonist character and of which the therapeutic effect may be expected to be superior to that of the hormone itself. PCT patent application WO 00/72815 and U.S. patent No 6,465,660B1 gives extensive literature on studies with Melatonin and potential therapeutic application of various ligands reported till date. Those various effects are exerted via the intermediary of specific Melatonin receptors. Molecular biology studies have demonstrated the existence of a number of receptor sub-types that are capable of binding that hormone (Trends Pharmacol. Sci., 1995, 16, p. 50; WO 97 04094). Melatonin acts on the CNS to affect neural mechanisms through receptors located in the brain. Additionally, a number of studies indicate the existence of direct effects of Melatonin in peripheral organs via peripheral melatonin receptors. Melatonin receptors are present in the heart, lungs, prostate gland, gonads, white blood cells, retina, pituitary, thyroid, kidney, gut and blood 4 r vessels (Withyachumnarnkul et al., Life Sci, 12 65, 1986). Three Melatonin receptor subtypes have been identified so far MT-I , MT-2 and Mel 1 c (Barreft et al., Biol. Signals Recept., 1999, 8: 6-14). There is evidence suggesting both Melatonin agonists and antagonists would be of potential therapeutic use for a variety of maladies and conditions. PCT application WO 00/72815, discuss in depth applications and use of such compounds and details of which are incorporated herein by reference. Also U. S. patent No. 6,465,660 and U. S. patent application publication number US 2003/0105087 discuss some tricyclic indole and tricyclic azaindole derivatives having very valuable pharmacological characteristics in respect of melatoninergic receptors. U. S. Pat. No. 4,839,377 and U. S. Pat. No. 4,855,314 refers to 5-substituted 3- aminoalkyl indoles. The compounds are said to be useful for the treatment of migraine. British Patent 2,035,310 refers to 3-aminoalkyl-1H-indole-5-thioamides and carboxamides. The compounds are said to be useful in treating hypertension, Raymond's disease and migraine. European Patent Publication 303,506 refers to 3-polyhydropyridyl-5- substituted-1 H-indoles. The compounds are said to have 5-HTi receptor agonists and vasoconstrictor activity and to be useful in treating migraine. European Patent Publication 354,777 refers to N-piperidinylindolylethyl-alkane sulfonamide derivatives. The compounds are said to be 5-HT-i receptor agonists and have vasoconstrictor activity and are useful in treating cephalic pain. European Patent Publication 438,230, refers to indole-substituted five- membered heteroaromatic compounds. The compounds are said to have "5-HTHike" receptor agonist activity and to be useful in the treatment of migraine and other disorders for which a selective agonist of these receptors is indicated. European Patent Publication 313,397 refers to 5-heterocyclic indole derivatives. The compounds are said to have exceptional properties for the treatment and prophylaxis of migraine, cluster headache and headache associated with vascular disorders. These compounds are also said to have exceptional "5-HTHike" receptor agonism. International Patent Publication WO 91/18897 refers to 5-heterocyclic indole derivatives. The compounds are said to have exceptional properties for the treatment and prophylaxis of migraine, cluster headache, and headache associated with vascular disorders. These compounds are also said to have exceptional "5-HTHike" receptor agonism. European Patent Publication 457,701 refers to aryloxy amine derivatives as having high affinity for 5-HT10 serotonin receptors. These compounds are said to be 5 useful for treating diseases related to serotonin receptor dysfunction, for example, migraine. European Patent Publication 497,512 A2, refers to a class of imidazole, triazole and tetrazole derivatives that are selective agonists for "5-HTrlike" receptors. These compounds are said to be useful for treating migraine and associated disorders. International Patent Publication WO 93/00086 describes a series of tetrahydrocarbazole derivatives, as 5-HTt receptor agonists, useful for the treatment of migraine and related conditions. International Patent Publication WO 93/23396, refers to fused imidazole and triazole derivatives as 5-HTi receptor agonists, for the treatment of migraine and other disorders. Schoeffter P. et al. refer to methyl 4-{4-[4-(1,1,3-trioxo-2H-1,2-benzoisothiazol- 2-yl)butyl]-1-piperazinyl}1H-indole-3-carboxylate as a selective antagonist for the 5- HT1A receptor in their paper "SDZ216-525, a selective and potent 5-HTiA receptor antagonist" European Journal of Pharmacology, 244, 251-257 (1993). International Patent Publication WO 94/06769, refers to 2-substituted-4- piperazine-benzothiophene derivatives that are serotonin 5-HT1A and 5-HT1d receptor agents useful in the treatment of anxiety, depression, migraine, stroke, angina and hypertension. Summary of the Invention: The present invention relates to compounds of general formula (I), its stereoisomers, its radioisotopes, its geometric forms, its N-oxide, its polymorphs, its pharmaceutical^ acceptable salts, its pharmaceutical^ acceptable solvates, its useful bioactive metabolite and any suitable combination of the above. The compounds of general formula (I) are as follows, Ra General Formula (I) wherein R1F R2, R3, R4, RS, R6, R7 R8I R9, R10, R„ and R12 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (CrC12)alkyl, (C2-Ci2)alkenyl, (C2-C12)alkynyl, (C3-C7)cycloalkyl, (C3- C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrCi2)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Ri and R2 or R2 and R3 or R3 and R4 or Rs and R6 or R6 and R7 or R7 and R8 or R8 and RG together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; or Rn and R12 together with carbon atoms to which they are attached may form a three to a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; R13 and R14 represents hydrogen, alkyl, aryl, aralkyl or together with nitrogen atom form a cyclic three to seven membered ring, optionally, R13 and R14 together may form a part of cyclic structure along with .the intervening nitrogen; the heterocycle may have either one, two or three double bonds; optionally it may also contain one to three heteroatom selected from the group of oxygen, nitrogen and sulfur, and includes ring fused with any carbocyclic or heterocyclic ring, which can be saturated or unsaturated; optionally, Rn and Ri3 together may form a part of cyclic structure along with the intervening nitrogen and carbon atoms; the heterocycle may have either one, two or three double bonds; optionally it may also contain one to three heteroatom selected from the group of oxygen, nitrogen and sulfur, and includes ring fused with any carbocyclic or heterocyclic ring, which can be saturated or unsaturated; "A" represents one or two hydrogens, oxygen, hydroxy, lower(Ci-C6)alkyl or lower(Ci-Ce)alkoxy; n -s r / "n" is an integer ranging from 1 to 8, prefcably 1 to 4, wherein the carbon chains, which "n" represents, may be either linear or branched; with the proviso that, i) whenever n =2, all of R,, R2, R3, R4 and R10are together hydrogens, and R13 and R14 are methyl or ethyl; then A is never either of =0 or -(H)2 and also includes the salts of such compounds, ii) whenever n =2, all of R1t R3, R4 and R10 are together hydrogens, R2 is methoxy, and R13 and R14 are methyl or ethyl; then A is never -(H)2 and also includes the salts of such compounds, iii) whenever n =2, all of R^ R3, R4 and R10 are together hydrogens, R2 is chloro, and R13 and R14 are methyl or ethyl; then A is never -(H)2 and also includes the salts of such compounds, iv) whenever n =2, all of Ri, R3, R4 and R2 are together hydrogens, R10 is phenyl, and R13 and R14 are methyl or ethyl; then A is never -(H)2 and also includes the salts of such compounds, v) whenever n =3, all of R1t R2, R3, R4 and R10are together hydrogens then R13 and R14 are methyl or ethyl; then A is never -(H)2 and also includes the salts of such compounds. Partial list of such compounds of general formula (I) is as follows: [2-(1-(Benzoyl)-1/-/-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)-1H-indol-3-yloxy)ethyl]dimethylamine; [2-( 1 -(Benzyl)-1 /-/-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)-1W-indol-3-yloxy)ethylJdimethylamine ; [2-(1 -(Benzoyl)-2-phenyl-1 H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 2-phenyl-1 /-/-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzyl)- 2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(2'-Bromobenzyl)- 2-phenyl-1 H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(Benzoyl)-2-methyl-1W-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 2- methyl -1tf-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(Benzyl)- 2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine ; [2-( 1 -(2'-Bromobenzyl)- 2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)-5-bromo-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5-bromo-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzyl)- 5-bromo-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1 -(2'-Bromobenzyl)- 5-bromo-1 H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1 -(Benzoyl)- 5-bromo-2-phenyl-1 H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5-bromo-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine [2-(1 -(Benzyl)- 5-bromo-2-phenyl-1 /-/-indol-3-yloxy)ethyl]dimethylamine ; 8 [2-(1-(2'-Bromobenzyl)- 5-bromo- 2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)- 5-bromo-2-methyl-1tf-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5-bromo- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzyl)- 5-bromo-2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 5-bromo- 2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine [2-(1-(Benzoyl)-5-chloro-1AV-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5-chloro-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(Benzyl)- 5-chloro-1W-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5-chloro-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(Benzoyl)- 5-chloro-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5-chloro-2-phenyl-1/7-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzyl)- 5-chloro-2-phenyl-1W-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5-chloro- 2-phenyl-1W-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)- 5-chloro-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5-chloro-2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzyl)- 5-chloro-2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 5-chloro- 2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine [2-(1-(Benzoyl)-6-chloro-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 6-chloro-1W-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzyl)- 6-chloro-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1 -(2'-Bromobenzyl)- 6-chloro-1 W-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(Benzoyl)- 6-chloro-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1 -(2'-Bromobenzoyl)- 6-chloro-2-phenyl-1 H-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(Benzyl)- 6-chloro-2-phenyl-1 H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 6-chloro- 2-phenyl-1/-/-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(Benzoyl)- 6-chloro-2-methyl-1 H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 6-chloro- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzyl)- 6-chloro-2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 6-chloro- 2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine [2-(1-(Benzoyl)-5,7-dichloro-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5,7-dichloro-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(Benzyl)- 5,7-dichloro-1 /-/-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 5,7-dichloro-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(Benzoyl)- 5,7-dichloro-2-phenyl-1 H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5,7-dichloro-2-phenyl-1H-indol-3-yloxy)ethyl] dimethylamine; [2-(1-(Benzyl)- 5,7-dichloro-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5,7-dichloro- 2-phenyl-1H-indol-3-yloxy)ethyl] dimethylamine ; 9 [2-(1-(Benzoyl)- 5,7-dicnloro-2-methyl-1W-indol-3-yloxy)ethyi]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5,7-dichloro- 2- methyl -1W-indol-3-yloxy)ethyl] dimethylamine » [2-(1-(Benzyl)- 5,7-dichloro-2- methyl -1 H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5,7-dichloro- 2- methyl -1 H-indol-3-yloxy)ethyl] dimethylamine; [2-(1-(Benzoyl)-5,7-dibromo-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5,7-dibromo-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(Benzyl)- 5,7-dibromo-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5,7-dibromo-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)- 5,7-dibromo-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5,7-dibromo-2-phenyl-1 AV-indol-3-yloxy)ethyl] dimethylamine; [2-(1-(Benzyl)- 5,7-dibromo-2-phenyl-1tf-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5,7-dibromo- 2-phenyl-1 H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzoyl)- 5,7-dibromo-2-methyl-1/-/-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5,7-dibromo- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine; [2-(1-(Benzyl)- 5,7-dibromo-2- methyl -1H-indol-3-yloxy)ethyI]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 5,7-dibromo- 2- methyl -1 H-indol-3-yloxy)ethyl] dimethylamine; [2-(1-(Benzoyl)-7-bromo-5-chloro-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 7-bromo-5-chloro-1H-indol-3-yloxy)ethyl]dimethylamine [2-(1-(Benzyl)- 7-bromo-5-chloro-1 H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 7-bromo-5-chloro-1/-/-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)- 7-bromo-5-chloro-2-phenyl-1/-/-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 7-bromo-5-chloro-2-phenyl-1/-/-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzyl)- 7-bromo-5-chloro-2-phenyl-1/-/-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 7-bromo-5-chloro- 2-phenyl-1H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzoyl)- 7-bromo-5-chloro-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 7-bromo-5-chloro- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzyl)- 7-bromo-5-chk>ro-2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 7-bromo-5-chloro- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine; [2-(1-(Benzoyl)-5-methoxy-1 H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5-methoxy-1AV-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzyl)- 5-methoxy-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5-methoxy-1 H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)- 5-methoxy-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5-methoxy-2-phenyl-1H-indol-3-yloxy)ethyl] dimethylamine; [2-(1-(Benzyl)- 5-methoxy-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine [2-(1-(2'-Bromobenzyl)- 5-methoxy- 2-phenyl-1H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzoyl)- 5-methoxy-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5-methoxy- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzyl)- 5-methoxy-2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5-methoxy- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine; or a stereoisomer, or a polymorph, or any suitable combination of above such as a nitrogen oxide thereof; a prodrug of the compound or the nitrogen oxide; a pharmaceutically acceptable salt of the compound, the nitrogen oxide, or the prodrug; or a solvate or hydrate of the compound, the nitrogen oxide, the prodrug or the pharmaceutically acceptable salt. The present invention also relates to the process for preparing the compound of the general formula (I) its stereoisomers, its radioisotopes, its geometric forms, its N-oxide, its polymorphs, its pharmaceutically acceptable salts, its pharmaceutically acceptable solvates, its useful bioactive metabolites and any suitable combination of above. In the case of the compounds of general formula (I), where tautomerism may exist, the present invention relates to all of the possible tautomeric forms and the possible mixture thereof. The present invention also relates to the stereoisomers, which as a rule are obtained as racemates that can be separated into the optically active isomers in a manner known per se. The present invention also relates to radio-labeled isotopes, which are identical to those defined in the general formula (I), but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number found usually in nature. Examples of isotopes that can be incorporated into compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorus, fluorine, chlorine, iodine, bromine and mTecnitium, exemplified by 2H, 3H, 11C, 13C, 14C, 13N, 1SN, 150, 18F, "Tc, 31P, S, 123l and 125l. Those compounds of general formula (I) as described earlier containing the aforementioned isotopes and/or other isotopes of other atoms are within the scope of this invention. In the case of the compounds of general formula (I) containing geometric isomerism the present invention relates to all of these geometric isomers. The term "nitrogen oxide" or "N-oxide" refers to the oxidation of at least one of the two nitrogens in the compounds of general formula (I) (e.g., mono- or di-oxide). The nitrogen mono-oxides may exist as a single positional isomer or a mixture of 2° positional isomers (e.g., a mixture of 1-N-oxide and 4-N-oxide piperazine or a mixture of 1-N-oxide and 4-N-oxide piperazines). Suitable pharmaceutical^ acceptable acid addition salts of compounds of the general formula (I) can be prepared of the aforementioned base compounds of this invention are those which form non-toxic acid addition salts, includes, salts containing pharmacologically acceptable anions, such as the hydrochloride, hydrobromide, hydroiodide, nitrate, sulfate, bisulfate, phosphate, acid phosphate, acetate, lactate, citrate, acid citrate, tartrate, bitartrate, succinate, maleate, fumarate, gluconate, saccharate, benzoate, methanesulfonate, ethanesulfonate, benezenesulfonate, p- tolunesulfonate, palmoate and oxalate. Pharmaceutically acceptable salts forming part of this invention are intended to define but not limited to the above list. Suitable pharmaceutical^ acceptable base addition salts of compounds of the general formula (I) can be prepared of the aforementioned acid compounds of this invention are those which form non-toxic base addition salts, includes, salts containing pharmaceutical^ acceptable cations, such as Lithium, sodium, potassium, calcium and magnesium, salts of organic bases such as lysine, arginine, guanidine. diethanolamine, choline, tromethamine and the like; ammonium or substituted ammonium salts. Pharmaceutically acceptable salts forming part of this invention are intended to define but not limited to the above list. In addition, pharmaceutically acceptable salts of the compound of formula (I) can be obtained by converting derivatives which have tertiary amino groups into the corresponding quarternary ammonium salts in the methods known in the literature by using quarternizing agents. Possible quartemizing agents are, for example, alkyl halides such as methyl iodide, ethyl bromide and n-propyl chloride, including arylalkyl halides such as benzyl chloride or 2-phenylethyl bromide. In the addition to pharmaceutically acceptable salts, other salts are included in the invention. They may serve as intermediates in the purification of the compounds, in the preparation of other salts, or in the identification and characterization of the compounds or intermediates. The pharmaceutically acceptable salts of compounds of formula (I) may exists as solvates, such as with water, methanol, ethanol, dimethylformamide, ethyl acetate, and the like. Mixtures of such solvates can also be prepared. The source of such solvate can be from the solvent of crystallization, inherent in the solvent preparation or 12 crystallization, or adventitious to such solvent. Such solvates are within the scope of this invention. The invention also encompasses the pharmaceutically acceptable prodrugs of the compounds of the formula (I). A prodrug is a drug which has been chemically modified and may be biologically in-active at the site of action, but which may be degraded or modified by one or more enzymatic or other in-vivo processes to the parent form. This prodrug should have a different pharmacokinetic profile than the parent, enabling easier absorption across the mucosal epithelium, better salt formation, or solubility, and/or improved systemic stability (an increase in the plasma half-life, for example). Typically, such chemical modifications include the following: 1. ester or amide derivatives which may be cleaved by esterases or lipases; 2. peptides which may be recognized by specific or non-specific proteases; or 3. derivatives that accumulate at a site of action through membrane selection of a prodrug from or a modified prodrug form; or 4. any combination of 1 to 3, above. Conventional procedures for the selection and preparation of suitable prodrug derivatives are described, for example, in H. Bundgard, Design of prodrugs, (1985). Another aspect of the present invention comprises of a pharmaceutical composition, containing at least one of the compounds of the general formula (I), their derivatives, their analogs, their derivatives, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates thereof as an active ingredient, together with pharmaceutically employed carriers, auxiliaries and the like. An effective amount of a compound of general formula (I) or its salt is used for producing medicaments of the present invention, along with conventional pharmaceutical auxiliaries, carriers and additives. The present invention also relates to the pharmaceutically acceptable compositions containing them, and the use of these compounds and compositions in medicine. The compounds of general formula (I) of this invention are useful in the treatment and/ or prophylaxis of a condition wherein modulation of 5-HT activity is desired. The compounds of general formula (I) of this invention are useful in the treatment and/ or prophylaxis of a condition wherein modulation of melatonin activity is desired. The compounds of general formula (I) of this invention are useful in the treatment and/ or prophylaxis of a condition wherein modulation of 5-HT and melatonin activities gives desired effect. The present invention provides for use of the compounds of general formula (I) according to above, for the manufacture of the medicaments for the potential use in the treatment and/ or prophylaxis of certain CNS disorders such as, anxiety, depression, convulsive disorders, obsessive-compulsive disorders, migraine headache, cognitive memory disorders e.g. Alzheimer's disease and age-related cognitive decline, ADHD (Attention Deficient Disorder/ Hyperactivity Syndrome), personality disorders, psychosis, paraphrenia, psychotic depression, mania, schizophrenia, schizophreniform disorders, withdrawal from drug abuse such as cocaine, ethanol, nicotine and benzodiazepines, panic attacks, chronobiological abnormalities, circadian rhythms, anxiolytic, osteoporosis, ischemic stroke, lower the risk of SIDS in young infants with low endogenous melatonin levels, reproduction, glaucoma, sleep disorders (including disturbances of Circadian rhythm) and also disorders associated with spinal trauma and / or head injury such as hydrocephalus. Compounds of the invention are further expected to be of use in the treatment of mild cognitive impairment and other neurodegenerative disorders like Alzheimer's disease, Parkinson's and Huntington's chorea. The compounds of the invention are also expected to be of use in the treatment of certain Gl (Gastrointestinal) disorders such as IBS (Irritable bowel syndrome) or chemotherapy induced emesis. The compounds of the invention are also expected to be of use in the modulation of eating behavior and these compounds can also be used to reduce morbidity and mortality associated with the excess weight. The present invention provides a method for the treatment of a human or a animal subject suffering from certain CNS disorders such as, anxiety, depression, convulsive disorders, obsessive-compulsive disorders, migraine headache, cognitive memory disorders e.g. Alzheimer's disease and age-related cognitive decline, ADHD (Attention Deficient Hyperactivity Disorder), personality disorders, psychosis, paraphrenia, psychotic depression, mania, schizophrenia, schizophreniform disorders, withdrawal from drug abuse such as cocaine, ethanol, nicotine and benzodiazepines, panic attacks, chronobiological abnormalities, circadian rhythms, anxiolytic, osteoporosis, ischemic stroke, lower the risk of SIDS in young infants with low endogenous melatonin levels, reproduction, glaucoma, sleep disorders (including disturbances of Circadian rhythm) and also disorders associated with spinal trauma and /or head injury such as hydrocephalus. Compounds of the invention are further expected to be of use in the treatment of mild cognitive impairment and other neurodegenerative disorders like Alzheimer's disease, Parkinson's and Huntington's chorea. The present invention also provides a method for modulating 5-HT and/ or melatonin receptor function desired in certain cases. Compounds of the present invention may be administered in combination with other pharmaceutical agents, such as apo-B/MTP inhibitors, MCR-4 agonists, CCK-A agonists, monoamine reuptake inhibitors, sympathomimetic agents, adrenergic receptor agonists, dopamine agonists, melanocyte-stimulating hormone receptor analogs, cannabinoid 1 receptor antagonists, melanin concentrating hormone antagonists, leptins, leptin analogs, leptin receptor agonists, galanin antagonists, lipase inhibitors, bombesin agonists, neuropeptide-Y antagonists, thyromimetic agents, dehydroepiandrosterone or analogs thereof, glucocorticoid receptor agonists or antagonists, orexin receptor antagonists, urocortin binding protein antagonists, glucagon-like peptide-1 receptor agonists, ciliary neurotrophic factors, AGRPs (human agouti-related proteins), ghrelin receptor antagonists, histamine 3 receptor antagonists or reverse agonists, neuromedin U receptor agonists, and the like, in a therapeutically effective amount via a suitable pharmaceutical composition, to achieve the desired effect in mammals as well as humans. The phrase "pharmaceutically acceptable" indicates that the substance or composition must be compatible chemically and/or toxicologically, with the other ingredients comprising a formulation, and/or the mammal being treated therewith. The terms "treating", "treat", or "treatment" embrace both preventative, i.e., prophylactic, and palliative treatment. The term "compounds of the present invention" (unless specifically identified otherwise) refer to compounds of Formulae (I), nitrogen oxides thereof, prodrugs of the compounds or nitrogen oxides, pharmaceutically acceptable salts of the compounds, nitrogen oxides, and/or prodrugs, and hydrates or solvates of the compounds, nitrogen oxides, salts, is and/or prodrugs, as well as, all stereoisomers (including diastereoisomers and enantiomers), tautomers and isotopically labeled compounds. The present invention also relates to the novel intermediates, represented by general formulae (II), (IV), (VI), (VII), (IX) and (X), their stereoisomers, their radioisotopes, their geometric forms, their N-oxide, their salts, their solvates and any suitable combination of above, involved in preparing the compounds of general formula (I) and the process of preparation of such intermediates. Detailed Description of the Invention: b The present invention relates to compounds of general formula (I), their stereoisomers, its radioisotopes, their geometric forms, their N-oxides, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates and any suitable combination of above. The present invention relates to compounds of general formula (I), described as follows, General Formula (I) wherein R1t R2, R3, R4, Rs, Re, R7, Rs, R9, R10, R11 and R12 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (CrCi2)alkyl, (C2-Ci2)alkenyl, (C2-C12)alkynyl, (C3-C7)cycloalkyl, (C3- C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (Ci-Ci2)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Ri and R2 or R2 and R3 or R3 and R4 or R5 and R6 or R6 and R7 or R7 and R8 or R8 and R9 together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; or R11 and Ri2 together with carbon atoms to which they are attached may form a three to a six memDered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms. R13 and R14 represents hydrogen, alkyl, aryl, aralkyl or together with nitrogen atom form a cyclic three to seven membered ring, optionally, R13 and R14 together may form a part of cyclic structure along with the intervening nitrogen; the heterocycle may have either one, two or three double bonds; optionally it may also contain one to three heteroatom selected from the group of oxygen, nitrogen and sulfur, and includes ring fused with any carbocyclic or heterocyclic ring, which can be saturated or unsaturated; optionally, Rn and Ri3 together may form a part of cyclic structure along with the intervening nitrogen and carbon atoms; the heterocycle may have either one, two or three double bonds; optionally it may also contain one to three heteroatom selected from the group of oxygen, nitrogen and sulfur, and includes ring fused with any carbocyclic or heterocyclic ring, which can be saturated or unsaturated. "A" represents one or two hydrogens, oxygen, hydroxy or lower(Ci-C6)alkoxy; "n" is an integer ranging from 1 to 8, preferably 1 to 4, wherein the carbon chains which "n" represents may be either linear or branched; with the proviso that i. whenever n =2, all of Ri, R2, R3, R4 and R10 are together hydrogens, and R13 and R14 are methyl or ethyl; then A is never either of =0 or -(H)2 and also includes the salts of such compounds, ii. whenever n =2, all of R1f R3, R4 and R10 are together hydrogens, R2 is methoxy, and R13 and Ri4 are methyl or ethyl; then A is never -(H)2 and also includes the salts of such compounds, iii. whenever n =2, all of R1f R3, R4 and R10are together hydrogens, R2 is chloro, and R13 and R14 are methyl or ethyl; then A is never -(H)2 and also includes the salts of such compounds, jv, whenever n =2, all of Ri, R3, R4 and R2 are together hydrogens, R10 is phenyl, and R13 and R14 are methyl or ethyl; then A is never -(H)2 and also includes the salts of such compounds, v, whenever n =3, all of R,, R2, R3, R4 and R10 are together hydrogens then R13 and R14 are methyl or ethyl; then A is never -(H)2 and also includes the salts of such compounds. Suitable groups represented by R1t R2, R3, R4, Rs, Re, R7. Re, Rg, Rio, R11 and Ri2 wherever applicable may be selected from halogen atom such as fluorine, chlorine, bromine or iodine; perhaloalkyl particularly perhalo(Ci-C6)alkyl such as fluoromethyl, difluoromethyl, trifluoromethyl, trifluoroethyl, fluoroethyl, difluoroethyl and the like; substituted or unsubstituted (CrC12)alkyl group, especially, linear or branched (Cr 17 C8)alkyl group, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, t-butyl, n- pentyl, iso-pentyl, hexyl, iso-hexyl, heptyl, octyl and the like; cyclo(C3-C7)alkyl group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, the cycloalkyl group may be substituted; cyclo(C3-C7)alkenyl group such as cyclopentenyl, cyclohexenyl, cycloheptynyl, cycloheptadienyl, cycloheptatrienyl and the like, the cycloalkenyl group may be substituted; (CrCi2)alkoxy, especially, (CrC6)alkoxy group such as methoxy, ethoxy, propyloxy, butyloxy, iso-propyloxy and the like, which may be substituted; cyclo(C3-C7) alkoxy group such as cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, cyclohexyloxy, cycloheptyloxy and the like, the cycloalkoxy group may be substituted; aryl group such as phenyl or naphthyl, the aryl group may be substituted; aralkyl group such as benzyl, phenethyl, C6H5CH2CH2CH2, naphthylmethyl and the like, the aralkyl group may be substituted and the substituted aralkyl is a group such as CH3C6H4CH2, Hal-C6H4CH2, CH3OC6H4CH2, CH3OC6H4CH2CH2 and the like; aralkoxy group such as benzyloxy, phenethyloxy, naphthylmethyloxy, phenylpropyloxy and the like, the aralkoxy group may be substituted; heterocyclyl groups such as aziridinyl, pyrrolidinyl, morpholinyl, piperidinyl, piperazinyl and the like, the heterocyclyl group may be substituted; heteroaryl group such as pyridyl, thienyl, furyl, pyrrolyl, oxazolyl, imidazolyl, oxadiazolyl, tetrazolyl, benzopyranyl, benzofuranyl and the like, the heteroaryl group may be substituted; heterocyclo(Ci-C6)alkyl, such as pyrrolidinealkyl, piperidinealkyl, morpholinealkyl, thiomorpholinealkyl, oxazolinealkyl and the like, the heterocydo(CrC6)alkyl group may be substituted; heteroaralkyl group such as furanylmethyl, pyridinylmethyl, oxazolylmethyl, oxazolylethyl and the like, the heteroaralkyl group may be substituted; heteroaryloxy, heteroaralkoxy, heterocycloalkoxy, wherein heteroaryl, heteroaralkyl, heterocycloalkyl and heterocyclylalkyl moieties are as defined earlier and may be substituted; acyl groups such as acetyl, propionyl or benzoyl, the acyl group may be substituted; acyloxy group such as CH3COO, CH3CH2COO, C6H5COO and the like which may optionally be substituted, acylamino group such as CH3CONH, CH3CH2CONH, C3H7CONH, C6HsCONH which may be substituted, (CrC6)monoalkylamino group such as CH3NH, C2H5NH, C3H7NH, C6H13NH and the like, which may be substituted, (Cr C6)dialkylamino group such as N(CH3)2, CH3(C2H5)N and the like, which may be substituted; arylamino group such as C6H5NH, CH3(C6H5)N, C6H4(CH3)NH, NH-C6H4- Hal and the like, which may be substituted; arylalkylamino group such as CeHsChfeNH, C6H5CH2CH2NH, C6H5CH2NCH3 and the like, which may be substituted; hydroxy(Cr C6)alkyl which may be substituted, amino(Ci-C6)alkyl which may be substituted; mono(Ci-C6)alkylamino(Ci-C6)alkyi, di(Ci-C6)alkylamino(Ci-C6)alkyl group which may be substituted, alkoxyalkyl group such as methoxy methyl, ethoxymethyl, methoxyethyl, 18 ethoxyethyl and the like, which may be substituted; aryloxyalkyl group such as C6H5OCH2, C6H5OCH2CH2, naphthyloxymethyl and the like, which may be substituted; aralkoxyalkyl group such as C6HsCH2OCH2, C6H5CH2OCH2CH2 and the like, which may be substituted; (CRC6)alkylthio, thio(CI-C6)alkyl which may be substituted, alkoxycarbonylamino group such as C2H5OCONH, CH3OCONH and the like which may be substituted; aryloxycarbonylamino group as C6H5OCONH, C6H5OCONCH3, C6H5OCONC2HS, C6H4CH3OCONH, C6H4(OCH3)OCONH and the like which may be substituted; aralkoxycarbonylamino group such C6H5CH2OCONH, C6H5CH2CH2OCONH, C6H5CH2OCON(CH3), C6HSCH2OCON(C2H5), C6H4CH3CH2OCONH, C6H4OCH3CH2OCONH and the like, which may be substituted; aminocarbonylamino group; (CrC6)alkylaminocarbonylamino group, di(Cr C6)alkylaminocart>onylamino group; (CI-C6)alkylamidino group, (CI-C6)alkylguanidino, di(Ci-C6)alkylguanidinogroups, hydrazino and hydroxylamino groups; carboxylic acid or its derivatives such as amides, like CONH2, alkylaminocarbonyi like CH3NHCO, (CH3)2NCO, C2HSNHCO, (C2H5)2NCO, arylaminocarbonyl like PhNHCO, NapthylNHCO and the like, aralkylaminocarbonyl such as PhCH2NHCO, PhCH2CH2NHCO and the like, heteroarylaminocarbonyl and heteroaralkylamino carbonyl groups where the heteroaryl groups are as defined earlier, heterocyclylaminocarbonyl where the heterocyclyl group is as defined earlier, carboxylic acid derivatives such as esters, wherein the ester moieties are alkoxycarbonyl groups such as unsubstituted or substituted phenoxycarbonyl, naphthyloxycarbonyl and the like; aralkoxycarbonyl group such as benzyloxycarbonyl, phenethyloxycarbonyl, naphthylmethoxycarbonyl and the like, heteroaryloxycarbonyl, heteroaralkoxycarbonyl, wherein the heteroaryl group is as defined earlier, heterocycloxycarbonyl where heterocycle is as defined earlier and these carboxylic acid derivatives may be substituted; sulfonic acid or its derivatives such as S02NH2, S02NHCH3, S02N(CH3)2, S02NHCF3, S02NHC0(C1-C6)alkyl, S02NHC0aryl where the aryl group is as defined earlier and the sulfonic acid derivatives may be substituted; phosphoric acid and its derivatives as P(0)(0H)2, P(0)(0Ci-C where A, R5, R6, R7, R8 and R9 are as defined earlier for compound of formula (I); by reductively alkylating a compound of formula (VIII) or its acid addition salt, NR13R14H (VIII) wherein R-|3 and R™ are as defined in relation to compound of formula (I) or precursor thereof; and thereafter if desired or necessary carrying out additional steps described above. The reaction may be performed in a solvent such as methanol or ethanol in the presence of hydrogen and a suitable catalyst such as palladium on carbon, sodium cyanoborohydride/acetic acid. Compounds of formula (IX) wherein R is acetyl, benzoyl are described in British patent application 1 306 230, the methods described therein are incorporated herein by reference. Scheme 6: Alternatively, compounds of formula (I) in which R13 is lower alkyl radical such as C^alkyl, a cycloalkyl containing 3-8 carbon atoms or a benzyl radical in which phenyl ring is substituted and R14 is hydrogen may be prepared from another compound of formula (X) R (X) where n, R1t R2, R3, R4, R10i R^ and Ri2 are as defined in relation to formula (I), Ri0 is a group R10 as defined in relation to formula (I) or protected form thereof; and in which Rb represents hydrogen atom or a benzyl group in which phenyl ring is substituted and is removable by hydrogenolysis, R is defined as a suitable N-protecting group or a group such as, where A, R5, R6, R7, R8 and R9are as defined earlier for compound of formula (I), with a compound of formula (XI) R-I4 (XI) wherein R13 and R14 are as defined in relation to compound of formula (I) or precursor thereof or with its acid addition salt thereof; and thereafter if desired or necessary carrying out additional steps described above. Similarly, when R10, R13 and Rn represents hydrogen atoms, these compounds may be prepared according to this invention by hydrogenolysing the corresponding indole derivative, in which above substituents represent one or more benzyl groups removable by hydrogenolysis. Furthermore, indole derivatives of the general formula (I) in which R13 is benzyl or a substituted benzyl group removable by hydrogenolysis and Ri4 is hydrogen, may according to this invention be prepared by partially hydrogenolysing the corresponding indole derivative in which Ri4 is identical to the substituent Ri3 above. The said hydrogenolysis is performed in a solvent such as ethanol in the presence of a suitable catalyst, e.g. palladium on carbon. The reaction is performed in a solvent such as methanol or ethanol in the presence of hydrogen and a suitable catalyst such as palladium on carbon. R = N-protecting group or Novel intermediates of general formula (II) are represented as given below, R (II) wherein Rt, R2, R3, R4, Rs, Re. R7. RS, RG and R10 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (Ci-C12)alkyl, (C2-Ci2)alkenyl, (C2-Ci2)alkynyl, (C3-C7)cycloalkyl, (C3- C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrC12)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkvlguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Ri and R2 or R2 and R3 or R3 and R4 or Rs and R6 or R6 and R7 or R7 and R8 or R8 and R9 together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; A represents one or two hydrogens, oxygen, hydroxy or lower(CrC6)alkoxy; and R is suitable protecting group such as acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and Fluoromethyleneoxycarbonyl (Fmoc) or a group defined as above; and its stereoisomers and its salts; with the proviso that whenever A is either of -CO or -CH2, then all of R^ R2, R3, R4 and R10 together are never hydrogens. Numerous processes to prepare the compounds of formula (II) can be found in literature. Some of them include US patent 3 860 608, J. Heterocyclic Chemistry, 16, 221 (1979), JP patent publication 57200362 A, and DE 111890. Alternatively, compounds of formula (II) may suitably be prepared by conventional methods for oxidization of indole-3-carboxaldehydes as described in literature (Chem. Pharm. Bull, 1985, 33, 1843, wherein HMPA, mCPBA are used as oxidizing agent). R11 R. (IV) wherein R1f R2, R3, R4, Rt1 and R12 may be same or different and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, Novel intermediates of general formula (IV) are represented as given below, substituted or unsubstituted groups selected from linear or branched (C1-C12)alkyl, (C2- Ci2)alkenyl, (C2-Ci2)alkynyl, (C3-C7)cycloalkyl, (C3-C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrCi2)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclyialkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Ri and R2 or R2 and>R3 or R3 and R4 together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; or Rn and R12 together with carbon atoms to which they are attached may form a three to a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; R10 represents hydrogen, formyl, substituted or unsubstituted groups selected from linear or branched (CrC12)alkyl, (C2-Ci2)alkenyl, (C2-C12)alkynyl, (C3- C7)cycloalkyl, (C3-C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (Ci-C12)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclyialkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, sulfonic acids and its derivatives, phosphoric acid and its derivatives. Ri3 and R14 represents hydrogen, alkyl, aryl, aralkyl or together with nitrogen atom form a cyclic three to seven membered ring, optionally, Ri3 and R14 together may form a part of cyclic structure along with the intervening nitrogen; the heterocycle may have either one, two or three double bonds; optionally it may also contain one to three heteroatom selected from the group of oxygen, nitrogen and sulfur, and includes ring fused with any carbocyclic or heterocyclic ring, which can be saturated or unsaturated; 30 r\ r optionally, Rn and R13 together may form a part of cyclic structure along with the intervening nitrogen and carbon atoms; the heterocycle may have either one, two or three double bonds; optionally it may also contain one to three heteroatom selected from the group of oxygen, nitrogen and sulfur, and includes ring fused with any carbocyclic or heterocyclic ring, which can be saturated or unsaturated; and "n" is an integer ranging from 1 to 8, preferably 1 to 4, wherein the carbon chains which "n" represents may be either linear or branched; and its stereoisomers and its salts; with the proviso that, i) whenever n =2, all of R^ R2, R3, R4 and Rio are together hydrogens then Ri3 and Ri4are methyl or ethyl; then either of Rn or R-I2 is other than hydrogen, ii) whenever n =2, all of R1t R3, R4 and Ri0are together hydrogens, R2 is methoxy, and R13 and R14 are methyl or ethyl; then either of Rn or RI2 is other than hydrogen, iii) whenever n =2, all of R^ R3, R4 and Ri0are together hydrogens, R2 is chloro, and R13 and R14 are methyl or ethyl; then either of Rn or RI2 is other than hydrogen, iv) whenever n =2, all of R1, R3, R4 and R2are together hydrogens, R10 is phenyl, and R13 and R14 are methyl or ethyl; then either of Rn or R12 is other than hydrogen, v) whenever n =3, all of R1f R2, R3, R,, and R10 are together hydrogens then RI3 and R i4are methyl or ethyl; then either of Rn or R-i2 is other than hydrogen. Numerous processes to prepare the compounds of formula (IV) can be found in literature. Some of them include US patent 3,509,163 and GB patent application 1,306,230. Novel intermediates of general formula (VI) are represented as given below, R. (VI) wherein R1t R2, R3, R4, R5, R6, R7, R8, Rg and Rio may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (Ci-C12)alkyl, (CrCi2)alkenyl, (C2-Ci2)alkynyl, (C3-C7)cycloalkyl, (Cr C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (Ci-CI2)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclyialkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Rt and R2 or R2 and R3 or R3 and R4 or R5 and R6 or R6 and R7 or R7 and R8 or R8 and Rg together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; "n" is an integer ranging from 1 to 8, preferably 1 to 4, wherein the carbon chains which "n" represents may be either linear or branched; R is suitable protecting group such as acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and Fluoromethyleneoxycarbonyl (Fmoc) or a group defined as above wherein A represents one or two hydrogens, oxygen, hydroxy or lower(Cr C6)alkoxy; Ra is defined as either hydrogen, halogen (such as chloro or bromo), lithio, trimethylsilyl, lower alkoxy, boronic acid or trifluoromethanesulfonate groups; and its stereoisomers and its salts. R = N-protecting group or Novel intermediates of general formula (VII) are represented as given below, R (VII) wherein R1f R2, R3, R4, R5, R6, R?i R8, R9i R10, Rn and R12 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (CrCi2)alkyl, (C2-Ci2)aJkenyl, (C2-Ci2)alkynyl, (C3-C7)cycloalkyl, (C3- C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrC12)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclyialkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxyrarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Rt and R2 or R2 and R3 or R3 and R4 or R5 and Re or R6 and R7 or R7 and R8 or Rs and R9 together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; or Rn and Ri2 together with carbon atoms to which they are attached may form a three to a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; "n" is an integer ranging from 1 to 8, preferably 1 to 4, wherein the carbon chains which "n" represents may be either linear or branched; R is suitable protecting group such as acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and Fluoromethyleneoxycarbonyi (Fmoc) or a group defined as above, wherein A represents one or two hydrogens, oxygen, hydroxy or lower(CrC6)alkoxy; and Lg is a leaving group as defined earlier; and its stereoisomers and its salts. Novel intermediates of general formula (IX) are represented as given below, (IX) wherein R1t R2, R3, R4, R5, R6, R7, R8, Rg, Rio, Rn and R12 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (CrCi2)alkyl, (C2-Ci2)alkenyl, (C2-Ci2)alkynyl, (C3-C7)cycloalkyl, (C3- C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrCi2)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Ri and R2 or R2 and R3 or R3 and R4 or R5 and R6 or R6 and R7 or R7 and Rg or Rs and Rg together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; or Rn and R12 together with carbon atoms to which they are attached may form a three to a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; "n" is an integer ranging from 1 to 8, preferably 1 to 4, wherein the carbon chains which "n" represents may be either linear or branched; R is suitable protecting group such as acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and Fluorenylmethyleneoxycarbonyl (Fmoc) or a group defined as above, wherein A represents one or two hydrogens, oxygen, hydroxy or lower(Ci-C6)alkoxy; and its stereoisomers and its salts. Novel intermediates of general formula (X) are represented as given below, (X) wherein R,, R2, R3, R4, R5, R6, R7I RS, RG R10, RN and R12 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (CI-CI2)alkyl, (C2-CI2)alkenyl, (C2-C12)alkynyl, (C3-C7)cycloalkyl, (C3- C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CI-CI2)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclyialkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Rt and R2 or R2 and R3 or R3 and R4 or R5 and Rs or R6 and R7 or R7 and R8 or R8 and R9 together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; or Rn and Ri2 together with carbon atoms to which they are attached may form a three to a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; R is suitable protecting group such as acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and Fluoromethyleneoxycarbonyl (Fmoc) or a group defined as above, wherein A represents one or two hydrogens, oxygen, hydroxy or lower(Cr C6)alkoxy; "n" is an integer ranging from 1 to 8, preferably 1 to 4, wherein the carbon chains which "n" represents may be either linear or branched; and Rb is either benzyl or hydrogen; and its stereoisomers and its salts. Procedure to prepare compounds of formula (X) is as reported in GB patent 1,306,230. The process includes hydrogenolysis of compounds of formula (I) wherein Ri3 and/or R14 are benzyl groups or hydrogens according to the method known in the art. The stereoisomers of compounds of general formula (I) may be prepared by one or more ways presented below: i) One or more of the reagents may be used in their optically active form. ii) Optically pure catalyst or chiral ligands along with metal catalyst may be employed in the reduction process. The metal catalysts may be employed in the reduction process. The metal catalyst may be Rhodium, Ruthenium, Indium and the like. The chiral ligands may preferably be chiral phosphines (Principles of Asymmetric synthesis, J. E. Baldwin Ed., Tetrahedron series, 14, 311-316). iii) The mixture of stereoisomers may be resolved by conventional methods such as forming a diastereomeric salts with chiral acids or chiral amines, or chiral amino alcohols, chiral amino acids. The resulting mixture of diastereomers may then be separated by methods such as fractional crystallization, chromatography and the like, which is followed by an additional step of isolating the optically active product by hydrolyzing the derivative (Jacques et. al., "Enantiomers, Racemates and Resolution", Wiley Interscience, 1981). 35 iv) The mixture of stereoisomers may be resolved by conventional methods such as microbial resolution, resolving the diastereomeric salts formed with chiral acids or chiral bases. Chiral acids that can be employed may be tartaric acid, mandelic acid, lactic acid, camphorsulfonic acid, amino acids and the like. Chiral bases that can be employed may be cinchona alkaloids, brucine or a basic amino group such as lysine, arginine and the like. Isotopically labelled compounds of the present invention are useful in drug and/or substrate tissue distribution and target occupancy assays. For example, isotopically labelled compounds are particularly useful in SPECT (single photon emission computed tomography) and in PET (positron emission tomography). The pharmaceutically acceptable salts forming a part of this invention may be prepared by treating the compound of formula (I) with 1-6 equivalents of a base such as sodium hydride, sodium methoxide, sodium ethoxide, sodium hydroxide, potassium t-butoxide, calcium hydroxide, calcium acetate, calcium chloride, magnesium € hydroxide, magnesium chloride and the like. Solvents such as water, acetone, ether, THF, methanol, ethanol, t-butanol, dioxane, isopropanol, isopropyl ether or mixtures thereof may be used. Organic bases such lysine, arginine, methyl benzylamine, ethanolamine, diethanolamine, tromethamine, choline, guanidine and their derivatives may be used. Acid addition salts, whereever applicable may be prepared by treatment with acids such as tartaric acid, mandelic acid, fumaric acid, maleic acid, lactic acid, salicyclic acid, citric acid, ascorbic acid, benzene sulfonic acid, p-toluene sulfonic acid, hydroxynaphthoic acid, methane sulfonic acid, malic acid, acetic acid, benzoic acid, succinic acid, palmitic acid, oxalic acid, hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid and the like in solvents such as water, alcohols, ethers, ethyl acetate, dioxane, DMF or a lower alkyl ketone such as acetone, or the mixtures thereof. Different polymorphs may be prepared by crystallization of compounds of general formula (I) under different conditions such as different solvents or solvent mixtures in varying proportions for recrystallization, various ways of crystallization such as slow cooling, fast cooling or a very fast cooling or a gradual cooling during crystallization. Different polymorphs may also be obtained by heating the compound, melting the compound and solidification by gradual or fast cooling, heating or melting under vacuum or under inert atmosphere, and cooling under either vacuum or inert atmosphere. The various polymorphs may be identified by either one or more of the following techniques such as differential scanning calorimeter, powder X-ray diffraction, IR spectroscopy, solid probe NMR spectroscopy and thermal gravimetry. """A, The pharmaceutical compositions of the present invention may be formulated in a conventional manner using one or more pharmaceutically acceptable carriers. Thus, the active compounds of the invention may be formulated for oral, buccal, intranasal, parental (e.g., intravenous, intramuscular or subcutaneous) or rectal administration or a form suitable for administration by inhalation or insufflation. "Therapeutically effective amount" is defined as 'an amount of a compound of the present invention that (i) treats or prevents the particular disease, condition, or disorder, (ii) attenuates, ameliorates, or eliminates one or more symptoms of the particular disease, condition, or disorder, or (iii) prevents or delays the onset of one or more symptoms of the particular disease, condition, or disorder described herein'. The dose of the active compounds can vary depending on factors such as the route of administration, age and weight of patient, nature and severity of the disease to be treated and similar factors. Therefore, any reference herein to a pharmacologically effective amount of the compounds of general formula (I) refers to the aforementioned factors. A proposed dose of the active compounds of this invention, for either oral, parenteral, nasal or buccal administration, to an average adult human, for the treatment of the conditions referred to above, is 0.1 to 200 mg of the active ingredient per unit dose which could be administered, for example, 1 to 4 times per day. For oral administration, the pharmaceutical compositions may take the form of, for example, tablets or capsules prepared by conventional means with pharmaceutically acceptable excipients such as binding agents (e.g., pregelatinised maize starch, polyvinylpyrrolidone or hydroxypropyl methylcellulose); fillers (e.g., lactose, microcrystalline cellulose or calcium phosphate); lubricants (e.g., magnesium stearate, talc or silica); disintegrants (e.g., potato starch or sodium starch glycolate); or wetting agents (e.g., sodium lauryl sulphate). The tablets may be coated by methods well known in the art. Liquid preparations for oral administration may take the form of, for example, solutions, syrups or suspensions, or they may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may be prepared by conventional means with pharmaceutically acceptable additives such as suspending agents (e.g., sorbitol syrup, methyl cellulose or hydrogenated edible fats); emulsifying agents (e.g., lecithin or acacia); non-aqueous vehicles (e.g., almond oil, oily esters or ethyl alcohol); and preservatives (e.g., methyl or propyl p-hydroxybenzoates or sorbic acid). For buccal administration, the composition may take the form of tablets or lozenges formulated in conventional manner. The active compounds of the invention may be formulated for parenteral administration by injection, including using conventional catheterization techniques or infusion. Formulations for injection may be 37 presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulating agents such as suspending, stabilizing and/or dispersing agents. Alternatively, the active ingredient may be in powder form for reconstitution with a suitable vehicle, e.g., sterile pyrogen- free water, before use. The active compounds of the invention may also be formulated in rectal compositions such as suppositories or retention enemas, e.g., containing conventional suppository bases such as cocoa butter or other glycerides. For intranasal administration or administration by inhalation, the active compounds of the invention are conveniently delivered in the form of an aerosol spray from a pressurized container or a nebulizer, or from a capsule using a inhaler or insufflator. In the case of a pressurized aerosol, a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas and the dosage unit may be determined by providing a valve to deliver a metered amount. The medicament for pressurized container or nebulizer may contain a solution or suspension of the active compound while for a capsule it preferably should be in the form of powder. Capsules and cartridges (made, for example, from gelatin) for use in an inhaler or insufflator may be formulated containing a powder mix of a compound of the invention and a suitable powder base such as lactose or starch. Aerosol formulations for treatment of the conditions referred to above (e.g., migraine) in the average adult human are preferably arranged so that each metered dose or "puff' of aerosol contains 20 |j.g to 1000 (xg of the compound of the invention. The overall daily dose with an aerosol will be within the range 100 ng to 10 mg. Administration may be several times daily, for example 2, 3, 4 or 8 times, giving for example, 1, 2 or 3 doses each time. The affinities of the compound of this invention for the various serotonin receptors are evaluated using standard radioligand binding assays and are described here. Radio ligand binding assays for various 5-HT receptor sub-types: i) Assay for 5HTia Materials and Methods: Receptor source: Human recombinant expressed in HEK-293 cells Radio ligand: [3H]-8-OH-DPAT (221 Ci/mmol) Final ligand concentration - [0.5 nM] 38 Reference compound: 8-OH-DPAT Positive control: 8-OH-DPAT Incubation conditions: Reactions are carried out in 50 mM TRIS-HCI (pH 7.4) containing 10 mM MgS04, 0.5 mM EDTA and 0.1% Ascorbic acid at room temperature for 1 hour. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. Radioactivity trapped onto the filters is determined and compared to control values in order to ascertain any interactions of test compound with the 5HTi a binding site. Literature Reference: • Hoyer D., Engel G., et al. Molecular Pharmacology of 5H^ and 5-HT2 Recognition Sites in Rat and Pig Brain Membranes: Radioligand Binding Studies with [3H]-5HT, [3H]-8-0H-DPAT, [125l]-lodocyanopindolol, [3H]-Mesulergine and [3H]-Ketanserin. Eur. Jml. Pharmacol. 118: 13-23 (1985) with modifications. • Schoeffter P. and Hoyer D. How Selective is GR 43175? Interactions with Functional 5-HT1A, 5HT1B, 5-HT1c, and 5-HT1D Receptors. Naunyn-Schmiedeberg's Arch. Pharmac. 340: 135-138 (1989) with modifications. ii) Assay for 5HTib Materials and Methods: Receptor source : Rat striatal membranes Radioligand : [125l]lodocyanopindolol (2200 Ci/mmol) Final ligand concentration - [0.15 nM] Non-specific determinant: Serotonin - [10 ^M] Reference compound: Serotonin Positive control: Serotonin Incubation conditions: Reactions are carried out in 50 mM TRIS-HCI (pH 7.4) containing 60 ^iM (-) isoproterenol at 37®C for 60 minutes. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. Radioactivity trapped onto the filters is determined and compared to control values in order to ascertain any interactions of test compound with the 5HT-|b binding site. Literature Reference: • Hoyer D., Engel G., et al. Molecular Pharmacology of 5HT! and 5-HT2 Recognition Sites in Rat and Pig Brain Membranes: Radioligand Binding Studies with [3H]-5HT, [3H]-8-OH-DPAT, [125l]-lodocyanopindolol, [3H]-Mesulergine and [3H]-Ketanserin. Eur. Jrnl. Pharmacol. 118: 13-23 (1985) with modifications. • Schoeffter P. and Hoyer D. How selective is GR 43175? Interactions with Functional 5-HTIA, 5HTIB, 5-HTIC, and 5-HT, Receptors. Naunyn-Schmiedeberg's Arch. Pharmac. 340: 135-138 (1989) with modifications. iii) Assay for 5HT1 d Materials and Methods: Receptor source : Human cortex Radioligand : [3H] 5-Carboxamidotryptamine (20-70 Ci/mmol) Final ligand concentration - [2.0 nM] Non-specific determinant: 5-Carboxamidotryptamine (5-CT) - [1.0 fxM] Reference compound : 5-Carboxamidotryptamine (5-CT) Positive control: 5-Carboxamidotryptamine (5-CT) Incubation conditions : Reactions are carried out in 50 mM TRIS-HCI (pH 7.7) containing 4 mM CaCI2l 100 nM 8-OH-DPAT, 100 nM Mesulergine, 10 uM Pargyline and 0.1% ascorbic acid at 25 °C for 60 minutes. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. Radioactivity trapped onto the filters is determined and compared to control values in order to ascertain any interactions of test compound with the cloned 5HT1D binding site. Literature Reference: • Waeber C., Schoeffter, Palacios J.M. and Hoyer D. Molecular Pharmacology of the 5-HT1D Recognition Sites: Radioligand Binding Studies in Human, Pig, and Calf Brain Membranes. Naunyn-Schmiedeberg's Arch. Pharmacol. 337: 595-601 (1938) with modifications. iv) Assay for 5HT2A Materials and Methods: Receptor source : Human Cortex Radioligand : [3H] Ketanserin (60-90 Ci/mmol) Fine' ligand concentration - [2.0 nM] Non-specific determinant: Ketanserin - [3.0 fiM] Reference compound : Ketanserin Positive control: Ketanserin Incubation conditions : Reactions are carried out in 50 mM TRIS-HCI (pH 7.5) at room temperature for 90 minutes. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. Radioactivity trapped onto the filters is determined and compared to control values in order to ascertain any interactions of test compound with the 5HT2A binding site. Literature Reference: • Leysen J. E., Niemegeers C. J., Van Nueten J. M. and Laduron P. M. [3H]Ketanserin: A Selective Tritiated Ligand for Serotonin2 Receptor Binding Sites. Mol. Pharmacol. 21: 301-314 (1982) with modifications. • Martin, G. R. and Humphrey, P. P. A. Classification Review: Receptors for 5- HT: Current Perspectives on Classification and Nomenclature. Neuropharmacol. 33(3/4): 261-273 (1994). v) Assay for 5HT2C Materials and Methods: Receptor source : Pig choroid plexus membranes Radioligand : [3H] Mesulergine (50-60 Ci/mmol) Final ligand concentration - [1.0 nM] Non-specific determinant: Serotonin - [100 |iM] Reference compound : Mianserin Positive control: Mianserin Incubation conditions: Reactions are carried out in 50 mM TRIS-HCI (pH 7.7) containing 4 mM CaCI2 and 0.1% ascorbic acid at 37 °C for 60 minutes. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. Radioactivity trapped onto the filters is determined and compared to control values in order to ascertain any interactions of test compound with the 5HT2C binding site. Literature Reference: • A. pazos, D. Hoyer, and J. Palacios. The Binding of Serotonergic Ligands to the Porcine Choroid Plexus: Characterization of a New Type of Serotonin Recognition Site. Eur. Jrnl. Pharmacol. 106: 539-546 (1985) with modifications. • Hoyer, D., Engel, G., et al. Molecular Pharmacology of 5HTi and 5-HT2 Recognition Sites in Rat and Pig Brain Membranes: Radioligand Binding Studies with [3H]-5HT, [3H]-8-OH-DPAT, [125l]-lodocyanopindolol, [3H]-Mesulergine and [3H]- Ketanserin. Eur. Jrnl. Pharmacol. 118: 13-23 (1985) with modifications. vi) Assay for 5HT3 Materials and Methods: Receptor source : N1E-115 cells Radioligand : [3H]-GR 65630 (30-70 Ci/mmol) Final ligand concentration - [0.35 nM] Non-specific determinant: MDL-72222 - [1.0 nM] Reference compound : MDL-72222 Positive control: MDL-72222 Incubation conditions : Reactions are carried out in 20 mM HEPES (pH 7.4) containing 150 mM NaCI at 25 °C for 60 minutes. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. Radioactivity trapped onto the filters is determined and compared to control values in order to ascertain any interactions of test compound with the 5HT3 binding site. Literature Reference: • Lummis S. C. R., Kilpatrick G. J. Characterization of 5HT3 Receptors in Intact N1E- 115 Neuroblastoma Cells. Eur. Jrnl. Pharmacol. 189: 223-227 (1990) with modifications. • Hoyer D. and Neijt H. C. Identification of Serotonin 5-HT3 Recognition Sites in Membranes of N1E-115 Neuroblastoma Cells by Radioligand Binding. Mol. Pharmacol. 33: 303 (1988). • Tyers M. B. 5-HT3 Receptors and the Therapeutic Potential of 5HT3 Receptor Antagonists. Therapie. 46:431-435 (1991). vii) Assay for 5HT4 Materials and Methods: Receptor source : Guinea pig striatal membranes Radioligand : [3H] GR-113808 (30-70 Ci/mmol) Final ligand concentration - [0.2 nM] Non-specific determinant: Serotonin (5-HT) - [30 |xM] Reference compound : Serotonin (5-HT) Positive control: Serotonin (5-HT) Incubation conditions: Reactions are carried out in 50 mM HEPES (pH 7.4) at 370C for 60 minutes. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. Radioactivity trapped onto the filters is determined and compared to control values in order to ascertain any interactions of test compound with the 5HT4 binding site. Literature Reference: • Grossman Kilpatrick, C., et al. Development of a Radioligand Binding Assay for 5HT4 Receptors in Guinea Pig and Rat Brain. Brit. J Pharmco. 109: 618-624 (1993). viii) Assay for 5HTsa Materials and Methods: Receptor source : Human recombinant expressed in HEK 293 cells Radioligand : [3H] LSD (60-87 Ci/mmol) Final ligand concentration - [1.0 nM] Non-specific determinant: Methiothepin mesylate - [1.0 |iM] Reference compound : Methiothepin mesylate Positive control: Methiothepin mesylate Incubation conditions: Reactions are carried out in 50 mM TRIS-HCI (pH 7.4) containing 10 mM MgS04 and 0.5 mM EDTA at 37 °C for 60 minutes. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. Radioactivity trapped onto the filters is determined and compared to control values in order to ascertain any interactions of test compound with the cloned 5HTsa binding site. Literature Reference: o V Rees S., et al. FEBS Letters, 355: 242-246 (1994) with modifications ix) Assay for 5HT6 Materials and Methods: Receptor source : Human recombinant expressed in HEK293 cells Radioligand : [3H]LSD (60-80 Ci/mmol) Final ligand concentration - [1.5 nM] Non-specific determinant: Methiothepin mesylate - [0.1 nM] Reference compound : Methiothepin mesylate Positive control: Methiothepin mesylate Incubation conditions: Reactions are carried out in 50 mM TRIS-HCI (pH 7.4) containing 10 mM MgCI2, 0.5 mM EDTA for 60 minutes at 37 °C. The reaction is terminated by rapid vacuum filtration onto glas_s fiber filters. Radioactivity trapped onto the filters is determined and compared to control values in order to ascertain any interactions of test compound(s) with the cloned serotonin - 5HT6 binding site. Literature Reference: • Monsma F. J. Jr., et al., Molecular Cloning and Expression of Novel Serotonin Receptor with High Affinity for Tricyclic Psychotropic Drugs. Mol. Pharmacol. (43): 320-327 (1993). x) Assay for 5-HT7 Materials and Methods: Receptor source : Human recombinant expressed in CHO cells Radioligand : [3H]LSD (60-80 Ci/mmol) Final ligand concentration - [2.5 nM] Non-specific determinant: 5-Carboxamidotryptamine (5-CT) - [0.1 pM] Reference compound : 5-Carboxamidotryptamine Positive control: 5-Carboxamidotryptamine Incubation conditions: Reactions are carried out in 50 mM TRIS-HCI (pH 7.4) containing 10 mM MgCI2, 0.5 mM EDTA for 60 minutes at 37 °C. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. Radioactivity trapped onto the filters is determined and compared to control values in order to ascertain any interactions of test compound(s) with the cloned serotonin - 5HT7 binding site. Literature Reference: • Y. Shen, E. Monsma, M. Metcalf, P. Jose, M Hamblin, D. Sibley, Molecular Cloning and Expression of a 5-hydroxytryptamine7 Serotonin Receptor Subtype. J. Biol. Chem. 268: 18200-18204. The following description illustrates the method of preparation of variously substituted compounds of general formula (I), according to the methods described herein. These are provided by the way of illustration only and therefore should not be construed to limit the scope of the invention. Commercial reagents were utilized without further purification. Room temperature refers to 25 - 30 °C. Melting points are uncorrected. IR spectra were taken using KBr and in solid state. Unless otherwise stated, all mass spectra were carried out using ESI conditions. 1H NMR spectra were recorded at 200 MHz on a Bruker instrument. Deuterated chloroform (99.8 % D) was used as solvent. TMS was used as internal reference standard. Chemical shift values are expressed in are reported in parts per million (5)-values. The following abbreviations are used for the multiplicity for the NMR signals: s=singlet, bs=broad singlet, d=doublet, t=triplet, q=quartet, qui=quintet, h=heptet, dd=double doublet, dt=double triplet, tt=triplet of triplets, m=multiplet. NMR, mass were corrected for background peaks. Specific rotations were measured at room temperature using the sodium D (589 nm). Chromatography refers to column chromatography performed using 60 - 120 mesh silica gel and executed under nitrogen pressure (flash chromatography) conditions. Description 1 : General procedure for the preparation of monoperphthalic acid (D1) To the mixture containing phthalic anhydride (2.22g.; 0.015 mole) and diethyl ether (25 mL), hydrogen peroxide solution (3.4 g.; 0.03 moles; as 30 % aqueous solution) was added and the reaction mixture was stirred at 25 °C to dissolve the anhydride. The reaction mixture was transferred to a separating funnel, ether layer was separated and aqueous layer was extracted with ether (3 X 10 mL). Combined ether extracts are, dried over sodium sulfate and this solution of monoperphthalic acid was used. Description 2 : 1-Benzyl-1H-indole (D 2) ROUTE I: In a three-necked round bottom flask equipped with pressure equalizing funnel, sodium hydride (0.6 g of 50 % suspension; 0.0125 mole) and DMF (8 mL) were taken. 45 Indole (0.01 mole) was added slowly at 0° C and the reaction mixture was stirred well. Then it was warmed to 25° C and stirring was continued for one hour, afterwards the reaction mixture was cooled and Benzyl bromide (2.05 g; 0.012 mole in 5 mL DMF) was added slowly from the pressure equalizing funnel over 5 minutes, and further stirred at 25 °C for 3 hours. After the completion of reaction (3-5 hours), the reaction mixture was poured in cold water and the product was extracted in ethyl acetate (2 X 25 mL). The combined organic extracts were washed with water, followed by brine, dried over anhydrous sodium sulfate and the product was isolated by distillation of solvent under reduced pressure. The product usually was an oily compound, which was used as such for the next step. The crude residue was purified by silica gel column chromatography using 30 % methanol in ethyl acetate as a mobile phase, to obtain the title compound, which was identified by IR, NMR and mass spectral analyses. ROUTE II : Instead of sodium hydride (0.6 g; 0.0125 mole), either sodium hydroxide (0.03 moles) or potassium hydroxide (0.03 moles) was taken and similar procedure was followed. Mass ion (M+Hf 284 Various substituted indole were treated with substituted benzyl bromide as described above. These compounds were identified by IR, NMR and mass spectral analyses. Following is the partial list of such compounds: List - 1: Description D 2 1-Benzyl-2-phenyl-1/-/-indole 314 298 362/ D 3 1-Benzyl-2-phenyl-5-methoxy-1H-indole D 4 1-Benzyl-2-phenyl-5-methyl-1/-/-indole D 5 1-Benzyl-5-bromo-2-phenyl-1H-indole 364 318/ D 6 1-Benzyl-5-chloro-2-phenyl-1H-indole 320 302 362/ D 7 1-Benzyl-5-fluoro-2-phenyl-1H-indole D 8 1-(2'-Bromobenzyl)-2-phenyl-1/7-indole 364 316 332/ D 9 1-(4'-Methylbenzyl)-5-fluoro-2-phenyl-1H-indole D10 1 -(4'-Methylbenzyl)-5-chloro-2-phenyl-1 H-indole D11 1-(2'-Bromo-4'-methylbenzyl)-2-phenyl-1H-indole 376/ 378 D12 1-(2'-Bromo-4'-isopropylbenzyl)-2-phenyl-1/-/-indole 404/ 406 D13 1-(4'-Fluorobenzyl)-5-chloro-2-phenyl-1H-indole 336/ 338 D14 1-Benzyl-2-methyl-1H-indole 222 D15 1-Benzyl-2-methyl-5-methoxy-1H-indole 252 D16 1-Benzyl-2,5-dimethyl-1H-indole 236 D17 1-Benzyl-5-bromo-2-methyl-1/-/-indole 300/ 302 D18 1 -Benzyl-5-chloro-2-methyl-1 /-/-indole 256/ 258 D19 1 -Benzyl-5-fluoro-2-methyl-1 H-indole 240 D20 1-(2'-Bromobenzyl)-2-methyl-1H-indole 300/ 302 D21 1 -(4'-Methylbenzyl)-5-fluoro-2-methyl-1 H-indole 254 D22 1-(4'-Methylbenzyl)-5-chloro-2-methyl-1H-indole 270/ 272 D23 1-(2'-Bromo-4'-methylbenzyl)-2-methyl-1W-indole 314/ 316 D24 1-(2'-Bromo-4'-isopropylbenzyl)-2-methyl-1/-/-indole 342/ 344 D25 1-(4'-Fluorobenzyl)-5-chloro-2-methyl-1/-/-indole 274 Description 26 : 1-Benzyl-2-phenyl-1H-indol-3-ol (D 26) ROUTE 1: 1-Benzyl indole (0.01 mole) dissolved in glacial acetic acid (15 mL) was transferred to three-necked flask. To this mixture monoperphpthalate solution (0.02 mole) in ether was added and stirred at 25 °C for 3 hours. After the completion of reaction, the volatile substances were removed under reduced pressure. To the residue was added ethyl acetate : water (1:1) mixture, followed by sodium bicarbonate. The organic layer was separated and the aqueous layer was extracted with ethyl acetate (3 X 20 mL). The combined organic extracts were washed with brine and the ethyl acetate was distilled off to obtain the crude intermediate. This intermediate was taken as such to the next step without purification. ROUTE 2: Alternatively 1-Benzyl-1H-indol-3-ol derivatives can also be obtained as reported in the Heterocycles, Vol. 30, No. 1, 1990, by reacting corresponding benzylindole with magnesium monoperphthalate. Various other derivatives of general formula (II) were prepared as described above. These compounds were identified by IR, NMR and mass spectral analyses. Following is the partial list of such compounds. List - 2: Description Mass ion (M+H)+ D26 1 -Benzyl-2-phenyl-1 H-indol-3-ol 300 D27 1 -Benzyl-2-phenyl-5-methoxy-1 H-indol-3-ol 330 D2B 1-Benzyl-2-phenyl-5-methyl-1H-indol-3-ol 314 D29 1 -Benzyl-5-bromo-2-phenyl-1 H-indoI-3-ol 378/ 380 D30 1 -Benzyl-5-chloro-2-phenyl-1 H-indol-3-ol 334/ 336 D31 1-Benzyl-5-fluoro-2-phenyl-1W-indol-3-ol 318 D32 1 -(2'-Bromobenzyl)-2-phenyl-1 H-indol-3-ol 378/ 380 D33 1-(4'-Methylbenzyl)-5-fluoro-2-phenyl-1H-indol-3-ol 332 D34 1-(4'-Methylbenzyl)-5-chloro-2-phenyl-1AV-indol-3-ol 348/ 350 D35 1-(2'-Bromo-4'-methylbenzyl)-2-phenyl-1H-indol-3-ol 392/ 394 D36 1-(2'-Bromo-4'-isopropylbenzyl)-2-phenyl-1H-indol-3-ol 420/ 422 D37 1-(4'-Fluorobenzyl)-5-chloro-2-phenyl-1H-indol-3-ol 352/ 354 D38 1-Benzyl-2-methyl-1AY-indol-3-ol 238 D39 1-Benzyl-2-methyl-5-methoxy-1/-/-indol-3-ol 268 D40 1-Benzyl-2,5-dimethyl-1H-indol-3-ol 252 D41 1 -Benzyl-5-bromo-2-methyl-1 H-indol-3-ol 316 / 318 » D42 1 -Benzy i-5-chloro-2-i .iethy I-1 H-indol-3-ol 272/ 274 D43 1-Benzyl-5-fluoro-2-methyl-1tf-indol-3-ol 256 D44 1-(2'-Bromobenzyl)-2-methyl-1H-indol-3-ol 316/ 318 D45 1-(4'-Methylbenzyl)-5-fluoro-2-methyl-1H-indol-3-ol 270 D46 1-(4'-Methylbenzyl)-5-chloro-2-methyl-1H-indol-3-ol 286/ 288 D47 1-(2'-Bromo-4'-methylbenzyl)-2-methyl-1H-indol-3-ol 330/332 D48 1-(2'-Bromo-4,-isopropylbenzyl)-2-methyl-1H-indcl-3-ol 358/ 360 D49 1-(4'-Fluorobenzyl)-5-chloro-2-methyl-1H-indol-3-ol 290/ 292 Description 50: 1-(3-Hydroxy-indol-1-yl)ethanone (D 50) According to the methods given in literature, the following N-acetylindoxyls were prepared and are listed below. These compounds were identified by IR, NMR and mass spectral analyses. List-3: Description Mass ion (M+H)+ D50 1 -(3-Hydroxy-indol-1 -yl)ethanone 176 D51 1-(5-Bromo-3-hydroxy-indol-1-yl)ethanone 254/ 256 D52 1 -(5-Chloro-3-hydroxy-indol-1 -yl)ethanone 210/ 212 D53 1-(5-Fluoro-3-hydroxy-indol-1-yl)ethanone 194 D54 1-(6-Chloro-3-hydroxy-indol-1-yl)ethanone 210/ 212 D55 1-(3-Hydroxy-5-methoxy-indol-1-yl)ethanone 206 D56 1-(5,7-Dibromo-3-hydroxy-indol-1-yl)ethanone 332/ 334/ 336 D57 1-(6-Chloro-5-methoxy-3-hydroxy-indol-1-yl)ethanone 240/ 242 D58 1-(6-Chloro-5-fluoro-3-hydroxy-indol-1-yl)ethanone 228/ 230 D59 1-(6-Bromo-5-methoxy-3-hydroxy-indol-1-yl)ethanone 284/ 286 D60 1-(6-Bromo-5-fluoro-3-hydroxy-indol-1-yl)ethanone 272/ 274 D61 1-(4-Chloro-5-fluoro-3-hydroxy-indol-1-yl)ethanone 228/ 230 D62 1-(4-Methoxy-5-fluoro-3-hydroxy-indol-1-yl)ethanone 224 D63 1-(3-Hydroxy-2-phenyl-indol-1-yl)ethanone 252 D64 1-(5-Bromo-3-hydroxy-2-phenyl-indol-1-yl)ethanone 330/ 332 D65 1 - (5-C h I o ro-3-h y droxy-2-ph enyl-indol-1 -yl)ethanone 206/ 288 D66 1-(5-Fluoro-3-hydroxy-2-phenyl-indoM-yl)ethanone 270 D67 1-(6-Chloro-3-hydraxy-2-phenyl-indol-1-yl)ethanone 286/ 288 D68 1-(3-Hydroxy-5-methoxy-2-phenyl-indol-1-yl)ethanone 282 D69 1-(5,7-Dibromo-3-hydroxy-2-phenyl-indol-1-yl)ethanone 408/ 410/ 412 D70 1-(6-Ch!oro-5-methoxy-3-hydroxy-2-phenylindol-1-yl)ethanone 316 / 318 D71 1-(6-Chloro-5-fluoro-3-hydroxy-2-phenyl-indol-1-yl)ethanone 304 D72 1-(6-Bromo-5-methoxy-3-hydroxy-2-phenyl-indol-1-yl)ethanone 360 / 362 D73 1-(6-Bromo-5-fluoro-3-hydroxy-2-phenyl-indol-1-yl)ethanone 348 / 350 D74 1-(4-Chloro-5-fluoro-3-hydroxy-2-phenyl-indol-1-yl)ethanone 304 / 306 D 75 1 -(4-Methoxy-5-fluoro-3-hydroxy-2-phenyl-indol-1 -yl)ethanone 300 D76 1-(3-Hydroxy-2-methyl-indol-1-yl)ethanone 190 D77 1-(5-Bromo-3-hydroxy-2-methyl-indol-1-yl)ethanone 268/ 270 D78 1-(5-Chloro-3-hydroxy-2-methyl-indol-1-yl)ethanone 224 A D79 1-(5-Fluoro-3-hydroxy-2-methyl-indol-1-yl)ethanone 208 \ ro-1 H-indol-3-yloxy)ethyl]dimethylamine 315/317/ 319 D102 [2-(1-Acetyl-5,7-Dichloro-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine 391/393/ 395 D103 [2-(1-Acetyl-5,7-Dichloro-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine 329/331/ 333 D104 [2-(1-Acetyl-5,7-Dibromo-1 H-indol-3-yloxy)ethyl]dimethylamine 403/405/ 407 D105 [2-(1-Acetyl-5,7-Dibromo-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine 479/481/ 483 D106 [2-(1-Acetyl-5,7-Dibromo-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine 417/419/ 421 D107 [2-(1-Acetyl-7-Bromo-5-chloro-1/-/-indol-3-yloxy)ethyl]dimethylamine 359/361 D108 [2-(1-Acetyl-7-Bromo-5-chlcro-2-phenyl-1H-indol-3- 435/437 yloxy)ethyl]dimethylamine D109 [2-(1-Acetyl-7-Bromo-5-chloro-2-methyl-1H-indol-3- 373/375 yloxy)ethyl]dimethylamine D110 [2-(1-Acetyl-5-Methoxy-1H-indol-3-yloxy)ethyl]dimethylamine 277 D111 [2-(1-Acetyl-5-Methoxy-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine 353 D112 [2-(1-Acetyl-5-Methoxy-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine 291 Description 113: [2-(1A/-indol-3-yloxy)ethyl]dimethylamine (D 113) According to the methods given in literature (US patent 3 860 608) the above derivatives were deacetylated. These compounds were identified by IR, NMR and mass spectral analyses. The following procedure also describes the method of synthesis of above compounds, [2-( 1-Acetyl-1/-/-indol-3-yloxy)ethyl]dimethylamine (0.015 mole), was taken in three necked flask along with sodium hydroxide (0.022 mole), water (ca 15 mL) and methanol (ca 15 mL). The reaction mixture was refluxed for 30 minutes to 2 hours. The reaction mixture was cooled to 25 °C and poured on to ice-cold water. The compound was extracted with ethyl acetate (3 X 20 mL), the combined organic extracts were washed with water and brine; dried over sodium sulfate; organic solvents were removed under reduced pressure and the residue was purified by column chromatography, on silica gel; using hexane (100 %) to triethylamine : ethyl acetate (2 : 98) gradual gradient as mobile phase, to obtain the compound of general formula (I) as thick oil, which was identified by IR, NMR and mass spectral analyses. The final desired compound of general formula (IV) can be further purified by preparation of their acid addition salts. List - 5: Mass ion (M+H)+ 205 281 219 283/285 359/361 297/298 239/241 315/317 253/255 239/241 315/317 253/255 273/275/ 277 349/351/ 353 287/289/ 291 361/363/ 365 437/439/ 441 375/377/ 379 317/319/ 321 Description D113 [2-(1 W-lndol-3-yloxy)ethyl]dimethylamine D114 [2-(2-Phenyl-1 H-indol-3-yloxy)ethyl]dimethylamine D115 [2-(2-Methyl-1 W-indol-3-yloxy)ethyl]dimethylamine D116 [2-(5-Bromo-1H-indol-3-yloxy)ethyl]dimethylamine D117 [2-(5-Bromo-2-phenyl-1 W-indol-3-yloxy)ethyl]dimethylamine D118 [2-(5-Bromo-2-methyl-1 W-indol-3-yloxy)ethyl]dimethylamine D119 [2-(5-Chloro-1/Y-indol-3-yloxy)ethyl]dimethylamine D120 [2-(5-Chloro-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine D121 [2-(5-Chloro- 2- methyl -1W-indol-3-yloxy)ethyl]dimethylamine D122 [2-(6-Chloro-1/Y-indol-3-yloxy)ethyl]dimethylamine D123 [2-(6-Chloro-2-phenyl-1W-indol-3-yloxy)ethyl]dimethylamine D124 [2-(6-Chloro-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine D125 [2-(5,7-Dichloro-1H-indol-3-yloxy)ethyl]dimethylamine D126 [2-(5,7-Dichloro-2-phenyl-1 H-indol-3-yloxy)ethyl]dimethylamine D127 [2-(5,7-Dichloro-2-methyl-1 W-indol-3-yloxy)ethyl]dimethylamine D128 [2-(5,7-Dibromo-1 H-indol-3-yloxy)ethyl]dimethylamine D129 [2-(5,7-Dibromo-2-phenyl-1 /-/-indol-3-yloxy)ethyl]dimethylamine D130 [2-(5,7-Dibromo-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine oD131 [2-(7-Bromo-5-chloro-1H-indol-3-yloxy)ethyl]dimethylamine D132 [2-(7-Bromo-5-chloro-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine D133 [2-(7-Bromo-5-chloro-2-methyl-1AV-indol-3-yloxy)ethyl]dimethylamine D134 [2-(5-Methoxy-1H-indol-3-yloxy)ethyl]dimethylamine D135 [2-(5-Methoxy-2-phenyl-1 A7-indol-3-yloxy)ethyl]dimethylamine D136 [2-(5-Methoxy-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine Example -1 : [2-(1-(Benzyl)-1H-indol-3-yloxy)ethy!Jdimethylamine Sodium hydride (60 % in mineral oil, 16.5 mmoles) was stirred with dimethyl formamide (ca 8 mL) in a ice-cooled, three necked round bottom flask. A solution of [2- (1/V-indol-3-yloxy)ethyl]dimethylamine (15 mmole), in dimethyl formamide (ca 5 mL) was then added dropwise to this cooled suspention of sodium hydride. After the addtion was complete, the reaction mixture was allowed to attain the room temperature (25 °C). After about one hour of stirring at 25 °C, a solution of Benzyl bromide (18 mmole) was added dropwise to this solution. The reaction was further stirred at 25 °C for next 3-4 hours. After the completion of reaction (TLC), reaction mixture was poured onto the ice cooled water and extracted by Ethyl acetate (3 X 20 mL). The combined organic extract was washed with water and brine, dried over sodium sulphate and the volatiles were evaporated under vacuume to get the product as a thick dark oil. The residue was purified by column chromatography, on silica gel; using hexane (100 %) to triethylamine : ethyl acetate (2 : 98) gradual gradient as mobile phase, to obtain the compound of general formula (I) as thick oil, which was identified by IR, NMR and mass spectral analyses. The final desired compound of general formula (I) can be further purified by preparation of their acid addition salts. Melting range (°C): Isolated as thick oil; Mass (m/z): 295.3(M+H)+. Example - 2 : [2-(1-(2'-Bromobenzyl)-1H-indol-3-yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C): Isolated as thick oil; Mass (m/z): 373, 375(M+H)+ Example - 3 : [2-(1 -(Benzoyl)-I H-indol-3-yl)oxyethyl]dimethylamine 393/395/ 397 331/333/ 335 235 311 249 c. Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C): Isolated as thick oil ; IR spectra (cm"1) : 1680., Mass (m/z): 309.3 (M+H)+; 1H-NMR (ppm) : 2.34 (s, 6H); 2.74-2.80 (t, 2H, J=5.4 Hz); 4.01-4.07 (t, 2H, J=5.4 Hz); 6.72 (s, 1H); 7.26-7.74 (m, 7H); 8.23-8.27 (d, 1H). Example - 4 : [2-(1 -(Benzyl)-2-methyl-1 H-indol-3-yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil, Mass (m/z): 309.3 (M+H)+ Example - 5 : [2-(1-(2'-Bromobenzoyl)-2-methyl-1H-indol-3-yl)oxyethyl] dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil; IR spectra (cm-1) :1680 (C=0), Mass (m/z): 401 (M+H)+ Example - 6 : [2-(1 -(2'-Bromobenzoyl)-2-phenyl-1 H-indol-3-yl)oxyethyl] dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil; IR spectra (cm'1) :1680(C=0), Mass (m/z): 463, 465 (M+H)+ Example - 7 : [2-(1-(Benzyl)-5-chloro-1H-indol-3-yl)oxyethyI]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil; Mass (m/z): 329, 331 (M+H)+ Example - 8 : [2-(1-(2'-Bromobenzyl)-5-chloro-1H-indol-3-yl)oxyethyl] dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) :Isolated as thick oil; Mass (m/z): 407, 409, 411 (M+H)+ Example - 9 : [2-(1 -(Benzoyl)-5-chloro-1 H-indol-3-yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil; IR spectra (cm"1) :1680(C=0), Mass (m/z): 343, 345 (M+H)+ Example -10 : [2-(1-(2'-Bromobenzyl)-5-chloro-2-methyl-1H-indol-3- yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil ;Mass (m/z): 421, 423, 425 (M+Hf Example-11 : [2-(1-(2'-Bromobenzoyl)-5-chloro-2-phenyl-1H-indol-3- yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C): Isolated as thick oil; IR spectra (cm"1) :1680 (C=0), Mass (m/z): 497, 499, 501 (M+H)+ Example -12 : [2-(1-(2'-Bromobenzyl)-5-bromo-1H-indol-3-yl)oxyethyl] dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C): Isolated as thick oil; Mass (m/z) : 451, 453, 455 (M+H)+; 1H-NMR (ppm):D 2.36 (s, 6H); 2.74-2.79 (t, 2H, J=5.4 Hz); 4.05-4.13 (t, 2H, J=5.4 Hz); 5.24 (s, 2H); 6.47-6.52 (dd, 1H);6.62 (s,1H);7.00-7.26 (m, 4H); 7.56-7.6 (dd, 1H); 7.82 (d, 1H). Example -13 : [2-(1-(Benzoyl)-5-bromo-1H-indol-3-yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C): Isolated as thick oil; IR spectra (cm'1) :1680 (C=0); Mass (m/z): 387, 389 (M+H)+ Example -14 : [2-(1-(2'-Bromobenzoyl)-5-bromo-1H-indol-3-yl)oxyethyl] dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil ; IR spectra (cm'1) :1680(C=0); Mass (m/z) : 465, 467, 469 (M+H)+ ;1H-NMR (ppm) :□ 2.35 (s, 6H); 2.75-2.81 (t, 2H); 4.00 (t, 2H); 7.26-7.47 (m, 4H); 7.68-7.77(dd, 2H). Example -15: [2-(1 -(Benzoyl)-5-bromo-2-methyl-1 H-indol-3-yl)oxyethyl] dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C): Isolated as thick oil; IR spectra (cm1) :1680(C=0); Mass (m/z): 401, 403 (M+H)+ Example - 16 : [2-(1-(2'-Bromobenzyl)-5-bromo-2-phenyl-1H-indol-3- yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C): Isolated as thick oil; Mass (m/z): 527, 529, 531 (M+Hf Example -17 : [2-(1-(Benzyl)-5-chloro-7-bromo-1H-indol-3-yl)oxyethyl] dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil, Mass (m/z): 407, 409, 411 (M+H)+ Example -18 : [2-(1 -{Benzoyl)-5-chloro-7-bromo-2-phenyl-1 H-indol-3-yl) oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil; IR spectra (cm1) :1680(C=0), Mass (m/z): 497, 499, 501 (M+H)+ Example -19 : [2-(1-(Benzyl)-5,7-dichloro-1H-indol-3-yl)oxyethyl] dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil; Mass (m/z) : 363, 365, 367 (M+H)+ Example - 20 : [2-(1-(2'-Bromobenzyl)-5,7-dichloro-2-methyl-1H-indol-3- yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C): Isolated as thick oil; Mass (m/z): 455, 457, 459 (M+H)+ Example-21 : [2-(1-Benzoyl)-5,7-dichloro-2-phenyl-1H-indol-3-yl) oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C): Isolated as thick oil ;IR spectra (cm"1) :1680 Mass (m/z): 453, 455, 457 (M+H)+ V Example - 22 : [2-(1-(Benzyl)-5,7-dibromo-1H-indol-3-yl)oxyethyl] dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil; Mass (m/z): 451, 453, 455 (M+H)+ Example - 23 : [2-(1-(Benzoyl)-5,7-dibromo-2-phenyl-1H-indol-3- yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil; IR spectra (cm-1) :1680; Mass (m/z): 541, 543, 545 (M+H)+ Example - 24 : [2-(1 -(2'-Bromobenzyl)-5-methoxy-1 H-indol-3-yl)oxyethyl] dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil Mass (m/z): 403, 405 (M+H)+ Example - 25 : [2-(1-(Benzoyl)-5-methoxy-1H-indol-3-yl)oxyethyl] dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil ;|R spectra (cm-1) :1680; Mass (m/z): 339.4 (M+Hf Example - 26 : [2-(1 -(2'-Bromobenzyl)-5-methoxy-2-methyl-1 H-indol-3- yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil; Mass (m/z): 417, 419 (M+H)+ Example - 27 : [2-(1 -(2'-Bromobenzyl)-5-methoxy-2-phenyl-1 H-indol-3- yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil; Mass (m/z): 479, 481 (M+H)+ Example - 28 : [2-(1-(Benzoyl)-5-methoxy-2-phenyl-1H-indol-3- yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil; IR spectra (cm"1): 1680; Mass (m/z): 415.5 (M+Hf Example - 29 : [2-(1 -(Benzoyl)-2-(4'-Methoxyphenyl)-1 H-indol-3- yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C) : Isolated as thick oil; IR spectra (cm"1) :1680; Mass (m/z): 415 (M+H)+ Example - 30 . [2-(1 -(Benzyl)-5-chloro-2-(4'-methoxyphenyl)-1 H-indol-3- yl)oxyethyl]dimethylamine Using essentially the general procedure described in example 1 and some non- critical variations, the above derivative was prepared. Melting range (°C): Isolated as thick oil; Mass (m/z): 435 (M+H)+ We Claim: 1. A compound of the general formula (I), its stereoisomers, its radioisotopes, its geometric forms, its N-oxide, its polymorphs, its Ly^ ^ pharmaceutical^ acceptable salts, its pharmaceutical^ acceptable solvates, its useful bio-active metabolite, any suitable combination of the above, wherein R1f R2, R3, R4, R5, Re, R7, Rs, R9, R10, R11 and R12 may bejsame or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (Ci-C12)alkyl, (C2-Ci2)alkenyl, (C2-Ci2)alkynyl, (C3-C7)cycloalkyl, (C3- C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrCi2)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like R, and R2 or R2 and R3 or R3 and R4 or R5 and R6 or R6 and R7 or R7 and R8 or R8 and Rg together with carbon atoms to which they are attached may form a five or a six -i. membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; or Rn and R12 together with carbon atoms to which they are attached may form a three to a six membered ring, optionally containing one or more double bonds and optionally containing one or more hc °roatoms selected from O, N, S and combinations of double bond and heteroatoms; R13 and R14 represents hydrogen, alkyl, aryl, aralkyl or together with nitrogen atom form a cyclic three to seven membered ring, optionally, R13 and R14 together may form a part of cyclic structure along with the intervening nitrogen; the heterocycle may have either one, two or three double bonds; optionally it may also contain one to three heteroatom selected from the group of oxygen, nitrogen and sulfur, and includes ring fused with any carbocyclic or heterocyclic ring, which can be saturated or unsaturated; optionally, Rn and R13 together may form a part of cyclic structure along with the intervening nitrogen and carbon atoms; the heterocycle may have either one, two or three double bonds; optionally it may also contain one to three heteroatom selected from the group of oxygen, nitrogen and sulfur, and includes ring fused with any carbocyclic or heterocyclic ring, which can be saturated or unsaturated; "A" represents one or two hydrogens, oxygen, hydroxy or lower(CrC6)alkoxy; "n" is an integer ranging from 1 to 8, preferably 1 to 4, wherein the carbon chains which "n" represents may be either linear or branched; with the proviso that, i) whenever n =2, all of R1f R2, R3, R4 and Rio are together hydrogens, and R13 and R14 are methyl or ethyl; then A is never either of =0 or -(H)2 and also includes the salts of such compounds, ii) whenever n =2, all of R1( R3, R4 and Ri0 are together hydrogens, R2 is methoxy, and R13 and R-|4 are methyl or ethyl; then A is never -(H)2 and also includes the salts of such compounds, iii) whenever n =2, all of R,, R3, R4 and Ri0are together hydrogens, R2 is chloro, and R13 and R14 are methyl or ethyl; then A is never -(H)2 and also includes the salts of such compounds, iv) whenever n =2, all of R1t R3, R4 and R2 are together hydrogens, R10 is phenyl, and R13 and R14 are methyl or ethyl; then A is never -(H)2 and also includes the salts of such compounds, v) whenever n =3, all of R1f R2, R3, R4 and Ri0are together hydrogens then R13 and R14 are methyl or ethyl; then A is never -(H)2 and also includes the salts of such compounds. [2-(1 -(Benzoyl)-2-phenyl-1 /-/-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1 -(Benzyl)- 2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(Benzoyl)-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 2- methyl -1W-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(Benzyl)- 2- methyl -1/-/-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)-5-bromo-1W-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5-bromo-1W-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzyl)- 5-bromo-1W-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5-bromo-1W-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(Benzoyl)- 5-bromo-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5-bromo-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine [2-(1-(Benzyl)- 5-bromo-2-phenyl-1/7-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5-bromo- 2-phenyl-1 H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)- 5-bromo-2-methyl-1 H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5-bromo- 2- methyl -1W-indol-3-yloxy)ethyl] dimethylamine ; [2-(1 -(Benzyl)- 5-bromo-2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 5-bromo- 2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine [2-(1 -(Benzoyl)-5-chloro-1 H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5-chloro-1/-/-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(Benzyl)- 5-chloro-1/i-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 5-chloro-1/-/-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)- 5-chloro-2-phenyl-1W-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5-chloro-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzyl)- 5-chloro-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5-chloro- 2-phenyl-1W-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)- 5-chloro-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5-chloro- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine [2-(1-(Benzyl)- 5-chloro-2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 5-chloro- 2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine [2-( 1 -(Benzoy l)-6-chloro-1 H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1 -(2-Bromobenzoyl)- 6-chloro-1W-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzyl)- 6-chloro-1H-indol-3-yloxy)ethyl]dimethylamine; 62 \ / [2-(1 -(2'-Bron lObenzyl)- 6-chloro-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(Benzoyl)- 6-chloro-2-phenyl-1/-/-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 6-chloro-2-phenyl-1H-indol-3-yioxy)ethyl]dimethylamine; [2-(1-(Benzyl)- 6-chloro-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(2'-Bromobenzyl)- 6-chloro- 2-phenyl-1 H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)- 6-chloro-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 6-chloro- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine [2-(1 -(Benzyl)- 6-chloro-2- methyl -1W-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 6-chloro- 2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine [2-(1 -(Benzoyl)-5,7-dichloro-1 H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5,7-dichloro-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzyl)- 5,7-dichloro-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5,7-dichloro-1 H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)- 5,7-dichloro-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5,7-dichloro-2-phenyl-1H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzyl)- 5,7-dichloro-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5,7-dichloro- 2-phenyl-1H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzoyl)- 5,7-dichloro-2-methyl-1tf-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5,7-dichloro- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzyl)- 5,7-dichloro-2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5,7-dichloro- 2- methyl -1H-indol-3-yloxy)ethyi] dimethylamine; [2-(1-(Benzoyl)-5,7-dibromo-1H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5,7-dibromo-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(Benzyl)- 5,7-dibromo-1W-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5,7-dibromo-1f/-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)- 5,7-dibromo-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5,7-dibromo-2-phenyl-1H-indol-3-yloxy)ethyl] dimethylamine; [2-(1-(Benzyl)- 5,7-dibromo-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5,7-dibromo- 2-phenyl-1H-indol-3-yloxy)ethyl] dimethylamine; [2-(1 -(Benzoyl)- 5,7-dibromo-2-methyl-1 H-indol-3-yloxy)ethyl]dimethylamine; 63 [2-(1-(2'-Bromobenzoyl)- 5,7-dibromo- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzyl)- 5,7-dibromo-2- methyl -1/-/-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 5,7-dibromo- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine; [2-(1-(Benzoyl)-7-bromo-5-chloro-1/-/-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 7-bromo-5-chloro-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(Benzyl)- 7-bromo-5-chloro-1 H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzyl)- 7-bromo-5-chloro-1AV-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(Benzoyl)- 7-bromo-5-chloro-2-phenyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(2'-Bromobenzoyl)- 7-bromo-5-chloro-2-phenyl-1/-/-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzyl)- 7-bromo-5-chloro-2-phenyi-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 7-bromo-5-chloro- 2-phenyl-1 H-indol-3-yloxy)ethyl] dimethylamine; [2-(1-(Benzoyl)- 7-bromo-5-chloro-2-methyl-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 7-bromo-5-chloro- 2- methyl -1H-indol-3-yIoxy)ethyl] dimethylamine ; [2-(1-(Benzyl)- 7-bromo-5-chloro-2- methyl -1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 7-bromo-5-chloro- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine; [2-(1-(Benzoyl)-5-methoxy-1W-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5-methoxy-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(Benzyl)- 5-methoxy-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5-methoxy-1W-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzoyl)- 5-methoxy-2-phenyl-1/-/-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzoyl)- 5-methoxy-2-phenyl-1/-/-indol-3-yloxy)ethyl] dimethylamine ; [2-(1 -(Benzyl)- 5-methoxy-2-phenyl-1 AY-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)- 5-methoxy- 2-phenyl-1H-indol-3-yloxy)ethyl] dimethylamine [2-( 1 -(Benzoyl)- 5-methoxy-2-methyl-1 H-indol-3-yloxy)ethyl]dimethylamine ; [2-(1-(2'-Bromobenzoyl)- 5-methoxy- 2- methyl -1H-indol-3-yloxy)ethyl] dimethylamine ; [2-(1-(Benzyl)- 5-methoxy-2- methyl -1W-indol-3-yloxy)ethyl]dimethylamine ; [2-(1 -(2-Bromobenzyl)- 5-methoxy- 2- methyl -1H-indol-3-yloxy)ethyl] L dimethylamine; or a stereoisomer, or a polymorph, or any suitable combination of above such as a nitrogen oxide thereof; a prodrug of the compound or the nitrogen oxide; a pharmaceutical^ acceptable salt of the compound, the nitrogen oxide, or the prodrug; or a solvate or hydrate of the compound, the nitrogen oxide, the prodrug or the pharmaceutical^ acceptable salt. 3. A pharmaceutical composition comprising of one or more pharmaceutical^ acceptable carrier, diluent/s, excipient/s or solvates along with a therapeutically effective amount of a compound according to Claim-1, its stereoisomers, its geometric forms, its N-oxides, its polymorphs, its pharmaceutically acceptable salts, or solvates. 4. A pharmaceutical composition according to Claim 3, in the form of a tablet, capsule, powder, lozenges, suppositories, syrup, solution, suspension or injectable, administered in, as a single dose or multiple dose units. 5. A process for the preparation of a compound of general formula (I), Re General Formula (I) its stereoisomers, its radioisotopes, its geometric forms, its N-oxide, its polymorphs, its pharmaceutically acceptable salts, its pharmaceutically acceptable solvates, its useful bio-active metabolite, any suitable combination of the above, wherein R1( R2, R3, R<», Rs. Re, R7. Rs, Rg, R10, R11 and R12 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (CrCi2)alkyl, (C2-Ci2)alkenyl, (C2-Ci2)alkynyl, \ ^ (C3-C7)cycloalkyl, (C3-C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrC12)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyi arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Ri and R2 or R2 and R3 or R3 and R4 or R5 and R6 or R6 and R7 or R7 and Re or R8 and R9 together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; or Rn and R12 together with carbon atoms to which they are attached may form a three to a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; R13 and R14 represents hydrogen, alkyl, aryl, aralkyl or together with nitrogen atom form a cyclic three to seven membered ring, optionally, Ri3 and R14 together may form a part of cyclic structure along with the intervening nitrogen; the heterocycle may have either one, two or three double bonds; optionally it may also contain one to three heteroatom selected from the group of oxygen, nitrogen and sulfur, and includes ring fused with any carbocyclic or heterocyclic ring, which can be saturated or unsaturated; optionally, Rn and R13 together may form a part of cyclic structure along with the intervening nitrogen and carbon atoms; the heterocycle may have either one, two or three double bonds; optionally it may also contain one to three heteroatom selected from the group of oxygen, nitrogen and sulfur, and includes ring fused with any carbocyclic or heterocyclic ring, which can be saturated or unsaturated; "A" represents one or two hydrogens, oxygen, hydroxy or lower(Ci-C6)alkoxy; "n" is an integer ranging from 1 to 8, preferably 1 to 4, wherein the carbon chains which "n" represents may be either linear or branched; which comprises of any one of the following routes, Route i). reacting a compound of formula (II) given below, Ri R (II) wherein all the symbols are as defined above; R represents either of a suitable N- protecting group, or a group such as, Re wherein all symbols are as deftied above, with a compound of formula (HI) or its acid addition salt, '■9 R« R11 -t'trK 'n \ R12 R« (III) wherein all the symbols are as defined above and Lg is a leaving group; Route ii): reacting a compound of formula (IV) given below, (IV) wherein all symbols except R10 are as defined above; Ri0 herein represents hydrogen, formyl, substituted or unsubstituted groups selected from linear or branched (Ci-Ci2)alkyJ, (C2-Ci2)alkenyl, (C2-Ci2)alkynyl, (C3-C7)cycloalkyl, (C3- C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrC12)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaraikoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, sulfonic acids and its derivatives, phosphoric acid and its derivatives; with a compound of formula (V) Rs (V) where A, R5, R6, R7, R8 and Rg, are as defined in relation to formula (I); and Lg is a leaving group as defined earlier; Route iii): reacting a compound of formula (VI) R. R (VI) wherein all symbols are as defined above, Ra is defined as either hydrogen, halogen (such as chloro or bromo), lithio, trimethylsily(^owerj)lkoxy, boronic acid or trifluoromethanesulfonate groups; and R is defined as a suitable N-protecting- group or a group such as, A Rs where all symbols are as defined earlier, and with a compound of formula (III) or its acid addition salt, Lg /Rl3 R11H- M2 (III) wherein all the symbols are as defined above and Lg is a leaving group either sulfonyloxy or halogeno; Route iv): reacting a compound of formula (VII) Ri R12 wherein all the symbols are as defined above and R is defined as a suitable N- protecting group, or a group such as, A R5 wherein all the symbols are as defined above, with a compound of formula (VIII) h-N ' n C", NR13RI4H (VIII) wherein all the symbols are as defined above; Route v): reacting a compound of formula (IX) ■)—COCH3 wherein all the symbols are as defined above with a compound of formula (VIII), NR13RI4H (VIII) wherein all the symbols are as defined above, followed by reduction; Route vi): reacting a compound of formula (X) (X) wherein all the symbols are as defined above, Rb represents hydrogen atom or a benzyl radical and R is defined as a suitable N-protecting group or a group such as, wherein all the symbols are as defined above with a compound of formula (XI) or precursor thereof, I Rl4 (XI) wherein all the symbols are as defined above and R is defined as a suitable N- wherein ail the symbols are as defined above; Route vii): displacing any of the substituent group/s in theamjtof formula (I) by hydrogen atom/s by carrying out complete hydrogenolysis or partial hydrogenolysis; / Route viii): chemically or catalytically reducing compounds containing - C(=0) group/s in the side chain, to the corresponding -C(OH,H) or -C(H,H) compound; 6. A process according to Claim 5, comprising of carrying out one or more of the following optional steps: i) removing any protecting group; ii) resolving the racemic mixture into pure enantiomers by the known methods and iii) preparing a pharmaceutical^ acceptable salt of a compound of formula (I) and/or iv preparing a pharmaceutical^ acceptable a prodrug thereof. 7. Nov^Wntermediates defined by general formula (II), R = N-protecting group or A Rg / / .Re (II) wherein R^ R2, R3, R4, R5, Re, R7, Rs, R9 and R10 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (CrC^alkyl, (C2-Ci2)alkenyl, (C2-Ci2)alkynyl, (C3-C7)cycloalkyl, (C3-C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrCi2)alkoxy, cyclo(C3- C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like F^ and R2 or R2 and R3 or R3 and R4 or R5 and R6 or R6 and R7 or R7 and R8 or R8 and R9 together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; R is suitable protecting group such as acetyl, trifluoroacetyl, t- butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and Fluoromethyleneoxycarbonyl (Fmoc) or a group defined as above wherein A represents one or two hydrogens, oxygen, hydroxy or lower(Ci-C6)alkoxy;; with the proviso that whenever A is either of =0 or-(H)2, then all of R1t R2, R3, R4 and R10 together are never hydrogens. 8. Novel intermediates of general formula (IV) are represented as given below, (IV) wherein R1t R2, R3, R4, Rn and R12 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (CrC12)alkyl, (C2-Ci2)alkenyl, (C2-Ci2)alkynyl, (C3-C7)cycloalkyl, (C3- C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrCi2)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, aryiamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbcnylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkyiguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Rt and R2 or R2 and R3 or R3 and R4 together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; or Rn and R12 together with carbon atoms to which they are attached may form a three to a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; R10 represents hydrogen, formyl, substituted or unsubstituted groups selected from linear or branched (Ci-C12)alkyl, (C2-C12)alkenyl, (C2-Ci2)alkynyl, (C3-C7)cycloalkyl, (C3-C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrC12)alkoxy, cyclo(C3- C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, sulfonic acids and its derivatives, phosphoric acid and its derivatives; Ri3 and R14 represents hydrogen, alkyl, aryl, aralkyl or together with nitrogen atom form a cyclic three to seven membered ring, optionally, R13 and R14 together may form a part of cyclic structure along with the intervening nitrogen; the heterocycle may have either one, two or three double bonds; optionally it may also contain one to three heteroatom selected from the group of oxygen, nitrogen and sulfur, and includes ring fused with any carbocyclic or heterocyclic ring, which can be saturated or unsaturated; optionally, Rn and R13 together may form a part of cyclic structure along with the intervening nitrogen and carbon atoms; the heterocycle may have either one, two or three double bonds; optionally it may also contain one to three heteroatom selected from the group of oxygen, nitrogen and sulfur, and includes ring fused with any carbocyclic or heterocyclic ring, which can be saturated or unsaturated; and "n" is an integer ranging from 1 to 8, preferably 1 to 4, wherein the carbon chains which "n" represents may be either linear or branched; and its stereoisomers and its salts; with the proviso that, i) whenever n =2, all of R1t R2l R3l R4 and R10 are together hydrogens then Ri3 and R14 are methyl or ethyl; then either of Rn or Ri2 is other than hydrogen, ii) whenever n =2, all of R1t R3, R4 and R10 are together hydrogens, R2 is methoxy, and R13 and R14 are methyl or ethyl; then either of Ru or R12 is other than hydrogen, iii) whenever n =2, all of R^ R3, R4 and R10 are together hydrogens, R2 is chloro, and R13 and R14 are methyl or ethyl; then either of Rn or R12 is other than hydrogen, iv) whenever n =2, all of Rh R3, R4 and R2are together hydrogens, R10 is phenyl, and R13 and R14 are methyl or ethyl; then either of Rn or R12 is other than hydrogen, and v) whenever n =3, all of R1f R2, R3, R4 and R 10 are together hydrogens then Ri3 and R14 are methyl or ethyl; then either of Rn or R12 is other than hydrogen. 9. Novel intermediates defined of general formula (VI), (VI) q wherein R1t R2, R3, R4, R5, R6, R7, R8, R9 and R10 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (CrCi2)alkyl, (C2-Ci2)alkenyl. (C2-Ci2)alkynyl, (C3-C7)cycloalkyl, (C3-C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrCi2)alkoxy, cyclo(C3- C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino. monoalkyiamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarfoonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Ri and R2 or R2 and R3 or R3 and R4 or Rs and R6 or R6 and R7 or R7 and R8 or R8 and R9 together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; "n" is an integer ranging from 1 to 8, preferably 1 t^ 4, wherein the carbon chains which "n" represents may be either linear or branched; R is suitable protecting group such as acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and Fluoromethyleneoxycarbonyl (Fmoc) or a group defined as above wherein A represents one or two hydrogens, oxygen, hydroxy or lower(CrC6)alkoxy; Ra is defined as either hydrogen, halogen (such as chloro or bromo), lithio, trimethylsilyl, lower alkoxy, boronic acid or trifluoromethanesulfonate groups; and its stereoisomers and its salts. R = N-protecting group or 10. Novel intermediates of general formula (VII) are represented as given below, R (VII) wherein Rt, R2, R3, R4, Rs, Re, R7, Ra, R9, R10, R11 and R12 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (CrCi^alkyl, (C2-C12)alkenyl, (C2-C12)alkynyl, (C3-C7)cycloalkyl, (C3-C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrCi2)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Ri and R2 or R2 and R3 or R3 and R4 or R5 and R6 or R6 and R7 or R7 and R8 or R8 and R9 together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; or Rn and R12 together with cc:Kon atoms to which they are attached may form a three to a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; "n" is an integer ranging from 1 to 8, preferably 1 to 4, wherein the carbon chains which "n" represents may be either linear or branched; R is suitable protecting group such as acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and Fluoromethyleneoxycarbony! (Fmoc) or a group defined as above, wherein A represents one or two hydrogens, oxygen, hydroxy or lower(Ci-C6)alkoxy; Lg is a leaving group as defined earlier; and its stereoisomers and its salts. 11. Novel intermediates of general formula (IX) are represented as given below, (IX) wherein R1t R2, R3, R4, Rs, Re, R7, Rs, R9, R10l Rn and R12 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (CrC12)alkyl, (C2-Ci2)alkenyl, (C2-C12)alkynyl, (C3-C7)cycloalkyl, (C3-C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrCi2)alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkyithio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Ri and R2 or R2 and R3 or R3 and R4 or Rs and R6 or R6 and R7 or R7 and R8 or R8 and R9 together with carbon atoms to which they are attached may form a five or a six membered ring, \ / optionally containing e or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; or Rn and R12 together with carbon atoms to which they are attached may form a three to a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; "n" is an integer ranging from 1 to 8, preferably 1 to 4, wherein the carbon chains which "n" represents may be either linear or branched; R is suitable protecting group such as acetyl, trifluoroacetyl, t-butoxycartoonyl (BOC), benzyloxycarbonyl (CBz) and Fluoromethyleneoxycarbonyl (Fmoc) or a group defined as above, wherein A represents one or two hydrogens, oxygen, hydroxy or lower(CrC6)alkoxy; its stereoisomers and its salts. R = N-protecting group or A R, 12. Novel intermediates of general formula (X) are represented as given below, R (X) wherein R1f R2, R3, R4, Rs, Re, R7, Rs, Rg, Rio, Rn and R12 may be same or different, and represent hydrogen, halogen, perhaloalkyl, hydroxy, thio, amino, nitro, cyano, formyl, amidino, guanidino, substituted or unsubstituted groups selected from linear or branched (Ci-C12)a!kyl, (C2-Ci2)alkenyl, (C2-Ci2)alkynyl, (C3- C7)cycloalkyl, (C3-C7)cycloalkenyl, bicycloalkyl, bicycloalkenyl, (CrC^alkoxy, cyclo(C3-C7)alkoxy, aryl, aryloxy, aralkyl, aralkoxy, heterocyclyl, heteroaryl, heterocyclylalkyl, heteroaralkyl, heteroaryloxy, heteroaralkoxy, heterocyclylalkyloxy, acyl, acyloxy, acylamino, monoalkylamino, dialkylamino, arylamino, diarylamino, aralkylamino, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, heterocyclylalkoxycarbonyl, heteroaryloxycarbonyl, hydroxyalkyl, aminoalkyl, monoalkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl arylalkyl, aralkoxyalkyl, alkylthio, thioalkyl, alkoxycarbonylamino, aralkyloxycarbonylamino, aminocarbonylamino, alkylaminocarbonylamino, alkylamidino, alkylguanidino, dialkylguanidino, hydrazino, hydroxylamino, carboxylic acid and its derivatives, sulfonic acids and its derivatives, phosphoric acid and its derivatives; or the adjacent groups like Rt and R2 or R2 and R3 or R3 and R4 or R5 and R6 or R6 and °7 or R7 and R8 or R8 and R3 together with carbon atoms to which they are attached may form a five or a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; or Rn and R12 together with carbon atoms to which they are attached may form a three to a six membered ring, optionally containing one or more double bonds and optionally containing one or more heteroatoms selected from O, N, S and combinations of double bond and heteroatoms; R is suitable protecting group such as acetyl, trifluoroacetyl, t- butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and Fluoromethyleneoxycarbonyl (Fmoc) or a group defined as above, wherein A represents one or two hydrogens, oxygen, hydroxy or lower(CrC6)alkoxy; "n" is an integer ranging from 1 to 8, preferably 1 to 4, wherein the carbon chains which "n" represents may be either linear or branched; and Rb is either benzyl or hydrogen; and its stereoisomers and its salts. 13. Use of the compounds as claimed in Claim 1, in combination with other pharmaceutical agents, such as apo-B/MTP inhibitors, MCR-4 agonists, CCK-A agonists, monoamine reuptake inhibitors, sympathomimetic agents, adrenergic receptor agonists, dopamine agonists, melanocyte-stimulating hormone receptor analogs, cannabinoid 1 receptor antagonists, melanin concentrating hormone antagonists, leptins, leptin analogs, leptin receptor agonists, galanin antagonists, lipase inhibitors, bombesin agonists, neuropeptide-Y antagonists, thyromimetic agents, dehydroepiandrosterone or analogs thereof, glucocorticoid receptor agonists or antagonists, orexin receptor antagonists, urocortin binding protein antagonists, glucagon-like peptide-1 receptor agonists, ciliary neurotrophic factors, AGRPs (human agouti-related proteins), ghrelin receptor antagonists, histamine 3 receptor antagonists or reverse agonists, neuromedin U receptor agonists, in a therapeutically effective amount via a suitable pharmaceutical composition, to achieve the desired effect in mammals as well as humans. 14. Use of compound of general formula (I), as defined in Claim 1 or a pharmaceutical composition as defined in Claim-3 for preparing the medicaments. 15. Use of a compound as claimed in Claim 1 for the treatment and/or prevention of clinical conditions such as anxiety, depression, convulsive disorders, obsessive- compulsive disorders, migraine headache, cognitive memory disorders, ADHD (Attention Deficient Disorder/ Hyperactivity Syndrome), personality disorders, 78 \YS psychosis, paraphrenia, psychotic depression, mania, schizophrenia, schizophreniform disorders, withdrawal from drug abuse, panic attacks, chronobiological abnormalities, circadian rhythms, anxiolytic, osteoporosis, ischemic stroke, lower the risk of SIDS in young infants with low endogenous melatonin levels, reproduction, glaucoma, sleep disorders and also disorders associated with spinal trauma and /or head injury. 16. Use of a compound as claimed in Claim 1 for the treatment of mild cognitive impairment and other neurodegenerative disorders like Alzheimer's disease, Parkinsonism and Huntington's chorea. 17. Use of a compound as claimed in Claim 1 for the treatment of certain Gl (Gastrointestinal) disorders such as IBS (Irritable bowel syndrome) or chemotherapy induced emesis. 18. Use of a compound as claimed in Claim 1 to reduce morbidity and mortality associated with the excess weight. 19. Use of a radiolabeled compound as claimed in Claim 1, as a diagnostic tool for modulating 5-HT and/or Melatonin receptor function. j / Dated this the 25th day of November 2003 H. S^JBRAMANIAM Of Subramani^rfyfiataraj & Associates Attorneys for Applicants 2. A compound according to Claim -1, which is selected from the following list: [2-(1-(Benzoyl)-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1 -(2'-Bromobenzoyl)-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(Benzyl)-1H-indol-3-yloxy)ethyl]dimethylamine; [2-(1-(2'-Bromobenzyl)-1 H-indol-3-yloxy)ethyl]dimethylamine;