Field of the invention The present invention relates to 5-lipoxygenase inhibitors. Compounds disclosed herein can be useful in the treatment of bronchial asthma, chronic obstructive pulmonary disorder, arthritis, type I diabetes, multiple sclerosis, allograft rejection, psoriasis, inflammatory bowel disease, ulcerative colitis, acne, atherosclerosis, cancer, pruritis, urticaria, atopic dermatitis, allergic rhinitis, other inflammatory and autoimmune diseases. Processes for the preparation of disclosed compounds, pharmaceutical compositions containing the disclosed compounds and their use as 5-lipoxygenase inhibitors are also provided. Background of the invention The lipoxygenases are non-heme, non-sulfur iron dioxygenases that act on lipid substrates containing one or more 1,4-pentadiene moieties to form hydroperoxides. 5-Lipoxygenase is a key enzyme that catalyses the first two steps in the oxygenation of arachidonic acid, which is converted to biologically active leukotrienes, namely leukotriene B4 (Clinical & Experimental Allergy Reviews, Volume 1, Number 3, November 2001, pp. 196-201(6)) and cysteinyl leukotrienes. Leukotrienes play important role in the pathophysiology of inflammatory / allergic diseases including bronchial asthma (Clinical & Experimental Allergy Reviews, Volume 1, Number 3, November 2001, pp. 264-273(10)), allergic rhinitis (Clinical & Experimental Allergy Reviews, Volume 1, Number 3, November 2001, pp. 235-243(9)), urticaria, atopic dermatitis (Clinical & Experimental Allergy Reviews, Volume 1, Number 3, November 2001, pp. 305-308(4)), chronic obstructive pulmonary disease (Eur. Respir. J., 2003, 22: 926-930). Incidence of allergic / inflammatory diseases are on the rise world over (Expert Opinion on Therapeutic Targets, Volume 3, Number 2, June 1999, pp. 229-240(12); Expert Opinion on Investigational Drugs, Volume 10, Number 7, 1 July 2001, pp. 1361-1379(19)). A variety of stimuli namely antigen-antibody reaction, cold or hyperosmotic shock etc, that elevates intracellular calcium level, can evoke arachidonic acid release from cell membrane under the influence of cytosolic phospholipase A2. Arachidonic acid is transferred to nuclear membrane by 5-lipoxygenase binding protein (FLAP) and acted upon by 5-lipoxygenase enzyme to generate 5-hydroperoxyeicosatetraenoic acid (HPETE). HPETE is converted to LTA4 by 5-lipoxygenase. Depending upon cell type, LTA4 is converted to either cysteinyl leukotrienes and/or leukotriene B4 (Clinical & Experimental Allergy Reviews, Volume 1, Number 3, November 2001, pp. 196-201(6); Current Drug Targets - Inflammation & Allergy, Volume 1, Number 1, March 2002, pp. 23-44(22); Drug Safety, Volume 26, Number 7, 2003, pp. 483-518(36)). Leukotrienes are generated by a variety of inflammatory cell types. Neutrophils and monocytes generate LTB4 whereas mast cells, basophils, eosinophils and bronchial epithelial cells produce cysteinyl leukotrienes. LTB4 acts as a chemo attractant for neutrophils through specific cell surface receptors. Cysteinyl leukotrienes, which include LTC4, LTD4 and LTE4, act on CysLTl and CysLT2 receptors and increase bronchial smooth muscle contractility, promote mucosal secretion, increase vascular permeability and encourage eosinophils recruitment. (Am. J. Respir. Crit. Care Med., Volume 157, Number 6, June 1998, S210-S213; Thorax 2000, 55, S32-S37; Clinical & Experimental Allergy Reviews, Volume 1, Number 3, November 2001, pp. 196-201(6); Clinical & Experimental Allergy Reviews, Volume 1, Number 3, November 2001, pp. 220-228(9); Drug Safety, Volume 26, Number 7, 2003, pp. 483-518(36)). There is evidence suggesting that cysteinyl leukotrienes can increase airway smooth muscle contractility in preclinical (Am. J. Respir. Crit. Care Med., Volume 157, Number 6, June 1998, S214-S219) and clinical studies (Clinical & Experimental Allergy Reviews, Volume 1, Number 3, November 2001, pp. 220-228(9)). Inhalation of leukotrienes also increases influx of inflammatory cells in the airway of animals (Clinical & Experimental Allergy Reviews, Volume 1, Number 3, November 2001, pp. 220-228(9)) and humans (Am. J. Respir. Crit. Care Med., Volume 157, Number 6, June 1998, S210-S213). In patients with asthma, urinary excretion of LTE4 correlates with exercise or cold air induced bronchoconstriction (Lancet, 1, 584, 1989) allergen induced early and late phase response (Clinical & Experimental Allergy, Volume 28, Number 11, 1 November 1998, pp. 1332-1339(8); Am. J. Respir. Crit. Care Med., Volume 157, Number 6, June 1998, S210-S213), as well as with reduction of FEV, in patients with nocturnal asthma (Am. J. Respir. Crit. Care Med., Volume 157, Number 6, June 1998, 8233-S237). Efficacy of leukotriene biosynthesis inhibitors and leukotriene receptor antagonists have been tested in numerous trials involving asthma patients (Clinical & Experimental Allergy Reviews, Volume 1, Number 3, November 2001, pp. 254-260(7); Drug Safety, Volume 26, Number 7, 2003, pp. 483-518(36); The New England Journal of Medicine, Volume 340:197-206, 1999; Am. J. Respir. Crit. Care Med., Volume 157, Number 6, June 1998, S233-S237). Evidence is emerging that leukotrienes also contribute towards pathophysiology of COPD. Two major cell types, neutrophils and macrophages, that generate LTB4 and are modulated by the same in turn are believed to participate in the pathogenesis of COPD (Am. J. Respir. Crit. Care Med., Volume 157, Number 6, June 1998, S210-S213). Patients with COPD exhibit elevated sputum neutrophilia and LTB4 levels (Chest. 2002; 121:1978-2008). Elevated levels of LTB4 were shown to be present in the exhaled breath condensate of COPD patients (Thorax 2003; 58: 585-588) as well as in patients experiencing exacerbation of COPD (Thorax 2003; 58: 294-298). Inhibitors of leukotriene biosynthesis as well as LTB4 receptor antagonists have shown to reduce airway reactivity, airway inflammation and airway neutrophilia in animals (J. Clin. Exp. Aller. 91, 917, 1992; J. Pharmacol. Exp. Then, 2001, 297: 458-466) as well as in human subjects (Thorax, 1996, 51: 1178-1184; Chest. 2002; 122: 289S-293S). Cysteinyl leukotriene antagonists like Montelukast has shown protective effect in hypertonic saline induced bronchoconstriction in COPD patients (Eur. Respir. J., 2003, 22: 926-930). Similarly, evidence is emerging based on animal and human data that leukotriene pathway modulators can play role in arthritis (J. Pharmacol. Exp. Ther., 1998, 285: 946-954), allergic rhinitis and urticaria (Clinical & Experimental Allergy Reviews, Volume 1, Number 3, November 2001, pp. 235-243(9)), cancer (Current Drug Targets - Inflammation & Allergy, Volume 3, Number 1, March 2004, pp. 19-33(15)), inflammatory bowel disease (Laboratory Investigation, 2005, 85, 808-822; Indian Journal of Experimental Biology Vol. 42, July 2004, pp. 667-673), acne (Dermatology 210(1), 36-38, 2005 ; Arch. Dermatol. 2003;139: 668-670), pruritis (J. Invest. Dermatol. 117, 1621, 2001), as well as atherosclerosis (N. Engl. J. Med. 2004, 350, 29-37; N. Engl. J. Med. 2004, 350, 4 -7, Med. Res. Rev. 24, 399, 2004). Several leukotriene receptor antagonists, Montelukast, Zafirlukast, and Pranlukast, and one 5-lipoxygenase inhibitor, Zileuton, has been launched in the market. Both categories of molecules have shown efficacy in clinical trials of bronchial asthma. Inhibitors of 5-lipoxygenase exhibit greater potential to exhibit efficacy in COPD as well because of their inhibitory effect on LTB4 mediated processes. However, commercially available 5-lipoxygenase inhibitor is associated with poor pharmacokinetic property and adverse events like elevation of hepatic transaminases. This has prompted the search for novel inhibitors of 5-lipoxygenase with improved pharmacokinetic profiles and reduced adverse effects. WO 96/14307, WO 96/40660, WO 98/03492 and WO 98/03494 encompass substituted benzylamine derivatives, which have been said to be useful in the diagnosis and treatment of feeding disorders such as obesity, bulimia and cardiovascular diseases such as essential hypertension and congestive heart failure due to the binding of these compounds to human Neuropeptide Yl receptors. WO 96/31485 discloses l,3-dihydro-l-(phenylalkyl)-2H-imidazol-2-one derivatives, which have been said to have PDE IV and cytokine activity. US 5,883,106 discloses compounds, which have been described to have the ability to inhibit 5-lipoxygenase enzyme. Summary of the invention The present invention provides 5-lipoxygenase inhibitors, which can be useful in the treatment of bronchial asthma, chronic obstructive pulmonary disorder, arthritis, type I diabetes, multiple sclerosis, allograft rejection, psoriasis, inflammatory bowel disease, ulcerative colitis, acne, atherosclerosis, cancer, pruritis, urticaria, atopic dermatitis, allergic rhinitis, other inflammatory and autoimmune diseases. Pharmaceutically acceptable salts, pharmaceutically acceptable solvates, stereoisomers, tautomers, racemates, regioisomers, prodrugs, metabolites, polymorphs or JV-oxides of these compounds having the same type of activity are also provided. Pharmaceutical compositions containing the compounds, which may also contain pharmaceutically acceptable carriers or diluents can be used for treatment of bronchial asthma, chronic obstructive pulmonary disorder, arthritis, type I diabetes, multiple sclerosis, allograft rejection, psoriasis, inflammatory bowel disease, ulcerative colitis, acne, atherosclerosis, cancer, pruritis, urticaria, atopic dermatitis, allergic rhinitis, other inflammatory and autoimmune diseases. Other aspects will be set forth in the accompanying description which follows and in part will be apparent from the description or may be learnt by the practice of the invention. In accordance with one aspect, there are provided compounds having the structure of Formula I, (Figure Removed)and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates, stereoisomers, tautomers, racemates, regioisomers, prodrugs, metabolites, polymorphs or N-oxides, wherein G can be O or S, Z can be -(CH2)n-X- or -X-(CH2)n-, X can be -NR,, -O- or -S-, n can be 0-2, R, can be hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl, R2 can be -CN, -CORs, 5-membered heteroaryl or hetereocyclyl, RS can be hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl, -OR,,-SR,or-N(R,)2. The following definitions apply to terms as used herein. The term "alkyl," unless otherwise specified, refers to a monoradical branched or unbranched saturated hydrocarbon chain having from 1 to 20 carbon atoms. This term can be exemplified by groups such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, n-decyl, tetradecyl, and the like. Alkyl groups may be substituted further with one or more substituents selected from alkenyl, alkynyl, alkoxy, cycloalkyl, cycloalkoxy, acyl, acylamino, acyloxy, alkoxycarbonylamino, azido, cyano, halogen, hydroxy, oxo, thiocarbonyl, carboxy, aryl, heterocyclyl, heteroaryl, arylthio, thiol, alkylthio, aryloxy, nitro, aminosulfonyl, aminocarbonylamino, -C(=O)heteroaryl, -C(=O)heterocyclyl, -NR(Rq, -CH-NOH, -(CH2)wC(=O)Re {wherein w is an integer from 0-4 and Rg is hydrogen, ORf, q, -NHOR7 (wherein R7 is alkyl, cycloalkyl, aryl, aralkyl, heteroaryl, heterocyclyl, heteroarylalkyl or heterocyclylalkyl) or -NHOH}, -C(-O)NRfRq , -NHC(=O)NRfRq , -O-Q-ONRfRq, -O-C(=O)Rf, -O-C(K))ORf {wherein Rf and Rq are hydrogen, alkyl, alkenyl, cycloalkyl, aryl, aralkyl, heterocyclyl, heteroaryl, (heterocyclyl)alkyl, (heteroaryl)alkyl)}, guanidine or -S(O)n Rd (wherein n is 0-2, Rd is alkyl, alkenyl, alkynyl, cycloalkyl, aralkyl, aryl, heterocyclyl, heteroaryl, heteroarylalkyl or heterocyclylalkyl). Unless otherwise constrained by the definition, alkyl substituents may be further substituted by 1-3 substituents selected from alkyl, carboxy, nitro, -NRfRq, -CH=NOH, -(CH2)wC(-O)Rg, -C(=O)NRfRq , -NHC(=O)NRfRq, -O-C(=O)NRfRq, -O-C(=O)Rf, -O-C(-O)ORf (wherein w, Rg, Rf and Rq are the same as defined earlier), hydroxy, alkoxy, halogen, CF3, cyano, guanidine or -S(0)nRd, (wherein n and Rd are the same as defined earlier); or an alkyl group also may be interrupted by 1-5 atoms of groups independently selected from oxygen, sulfur or -NRa- {wherein Ra is selected from hydrogen, alkyl, cycloalkyl, alkenyl, alkynyl, aryl, acyl, aralkyl,-C(=O)ORf (wherein Rf is the same as defined earlier) or -C(=O)NRfRq (wherein Rf and Rq are as defined earlier)}. Unless otherwise constrained by the definition, all substituents may be substituted further by 1-3 substituents selected from alkyl, carboxy, -NR,Rq, -CH=NOH, -(CH2)WC(=O) Rg, -C(-O)NRfRq , -NHC(=O)NRfRq, -O-C(=O)NRfRq, -O-C(=O)Rf, -O-C(=O)ORf, (wherein w, Rg, Rf and Rq are the same as defined earlier), hydroxy, alkoxy, halogen, CFa, cyano, guanidine or S(O)nR -O-C(=O)Rf, -O- C(=O)ORf (wherein w, Rg, Rt and Rq are the same as defined earlier) guanidine or (SO)nRd (wherein n and R -O-C(=O)NRfRq, -O-C(=O)R,, -O- C(=0)ORf, (wherein w, Rg, Rf and Rq are the same as defined earlier), cyano, guanidine or (SO),,Rd (wherein n and Rd are the same as defined earlier). The term "(cycloalkyl)alkyl" refers to alkyl-cycloalkyl group linked through alkyl portion, wherein the alkyl and cycloalkyl are as defined earlier. The term "alkoxy" denotes the group O-alkyl wherein alkyl is the same as defined above. The term "aryl," unless otherwise specified, refers to carbocyclic aromatic groups, for example, phenyl, biphenyl or napthyl ring and the like, optionally substituted with 1 to 3 substituents selected from halogen (e.g. F, Cl, Br, I), hydroxy, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkoxy, alkoxy, acyl, aryloxy, CF3, cyano, nitro, -NRfRq, -CH=NOH, - (CH2)wC(=O)Rg, -C(=O)NRfRq , -NHC(=O)NRfRq , -O-C(=O)NRfRq, -O-C(=O)Rf, -O- C(=O)ORf, (wherein w, Rg , Rf and Rq are the same as defined earlier), guanidine, -(SO)nRd (wherein n and Rd are the same as defined earlier), carboxy, heterocyclyl, heteroaryl, (helerocyclyl)alkyl, (heteroaryl)alkyl or aminocarbonylamino. The aryl group optionally may be fused with a cycloalkyl group, wherein the cycloalkyl group may optionally contain heteroatoms selected from O, N or S. The term "aralkyl," unless otherwise specified, refers to alkyl-aryl linked through an alkyl portion (wherein alkyl is as defined above) and the alkyl portion contains 1-6 carbon atoms and aryl is as defined above. Examples of aralkyl groups include benzyl, phenyl ethyl, phenylpropyl and the like. The term "aryloxy" denotes the group O-aryl, wherein aryl is as defined above. The term "cycloalkoxy" denotes the group O-cycloalkyl, wherein cycloalkyl is as defined above. The term "carboxy," as defined herein, refers to -C(=O)ORf, wherein Rf is the same as defined above. The term "heteroaryl," unless otherwise specified, refers to an aromatic ring structure containing 5 or 6 ring atoms, or a bicyclic aromatic group having from 8 to 10 ring atoms, with one or more heteroatom(s) independently selected from N, O or S optionally substituted with 1 to 4 substituent(s) selected from halogen (e.g., F, Cl, Br, I), hydroxy, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkoxy, acyl, carboxy, aryl, alkoxy, oxo, aralkyl, cyano, nitro, heterocyclyl, heteroaryl, -NRfRq, -CH=NOH, -henyl]thio|phenyl)tetrahydro-2//-pvran-4-carbonitrile A mixture of A^-(4-{[3-(4-cyanotetrahydro-2//-pyran-4-yl)phenyl]thio} phenyl) hydrazinecarboxamide (1.0 g, 2.72 mmol) (example 6) and acetamidine hydrochloride (1.16 g, 12.22 mmol) was evacuated for about 15 minutes. Dry dimethylformamide (10 ml) was added to it under nitrogen atmosphere and the mixture was heated at about 120° C for about 7-8 hours. The solvent was evaporated under vacuum and a saturated solution of potassium carbonate was added till the mixture became basic. It was then extracted with ethyl acetate, washed with water, dried over anhydrous sodium sulphate, filtered and the solvent evaporated under vacuum to afford a colorless oily residue. Column chromatography over silica gel using ethyl acetate and hexane (4:1) gave the title product as a white fluffy solid. Yield: 0.500 g. 'H NMR (300 MHz, CDC13): 5 9.78 (brs, 1H, Ar-H), 7.57 (s, 1H, Ar-H), 7.44-7.39 (m, 4H, Ar- H), 7.32-7.24 (m, 3H, Ar-H), 4.10-4.07 (m, 2H, -OCH2), 3.93-3.86 (m, 2H, -OCH2), 2.16 (s, 311, -CH3) and 2.13-1.97 (m, 4H, 2x-CH2) Mass Spectrum (m/z, *~ve ion mode): 393 [M++l] Example 8: Synthesis of 4-(3-([4-(5-oxo-4,5-dihvdro-l//-l,2,4-triazol-l-vnphenvl]thio} phenyl)tetrahydro-2//-pyran-4-carbonitrile A mixture of vV-(4-{[3-(4-cyanotetrahydro-2//-pyran-4-yl)phenyl]thio}phenyl) hydrazinecarboxamide (2.0 g, 5.43 mmol) (example 6) and formamidine acetate (2.54 g, 24.45 mmol) was evacuated for about 15 minutes. Dry dimethylformamide (15 ml) was added under nitrogen atmosphere and the mixture was cooled to 0° C. Glacial acetic acid (5 ml) was added at 0° C under nitrogen atmosphere and the mixture was stirred at room temperature for about 30 minutes. The contents of the reaction were then heated at about 120° C for about 7-8 hours. The solvent was evaporated under vacuum and a saturated solution of sodium bicarbonate was added till the solution became basic. A white semisolid separated out. The reaction mixture was extracted with ethyl acetate, washed with water, dried over anhydrous sodium sulphate, filtered and the solvent evaporated under vacuum to afford a light yellow solid, which upon crystallization in ethyl acetate and methanol gave the title compound as a light yellow solid. Yield: 1.60 g 'H NMR (400 MHz, DMSO-^): 8 12.33 (brs, 1H, -NH), 9.87 (s, 1H, Ar-H), 7.77-7.75 (m, 2H, Ar-H), 7.56-7.35 (m, 5H, Ar-H), 7.27-7.25 (m, 1H, Ar-H), 4.02-3.98 (m, 2H, -OCH2), 3.67- 3.60 (m, 2H, -OCH2) and 2.11-2.98 (m, 4H, 2x-CH2). Mass Spectrum (m/z, \~ve ion mode): 379 [M++l]. Example 9: Synthesis of 4-(3-{[4-(4-ethyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenvl1thio}phenvl)tetrahvdro-2//-pvran-4-carbonitrile (Compound No. 28) Solid potassium carbonate (0.158 g, 1.14 mmol) was added to a solution of 4-(3-{[4-(3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl) phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carbonitrile (0.100 g, 0.2544 mmol) (example 7) in dry dimethylformamide (2 ml). The reaction mixture was stirred at room temperature for about 5 minutes. Ethyl iodide (0.105 g, 0.763 mmol) was added to it and the mixture was heated at about 90-100° C for about 12 hours. The solvent was evaporated under vacuum, water was added to it and the mixture extracted with ethyl acetate. The organic layer was washed with water, dried over anhydrous sodium sulphate, filtered and the solvent evaporated under vacuum to afford a brown residue. The product was purified by preparative thin layer chromatography over silica gel using ethyl acetate and hexane (3:2) as the eluant. Yield: 0.080 g. 'H NMR (300 MHz, CDC13): 8 7.55 (s, 1H, Ar-H), 7.43-7.39 (m, 4H, Ar-H), 7.26-7.24 (m, 3H, Ar-H), 4.11-4.06 (m,2H,-OCH2), 3.94-3.83 (m, 4H, -OCH2 & -NCH2), 2.17-2.02 (m, 7H, Ar-CH3 & 2x-CH2) and 1.37 (t, 3H, 6.0 Hz, -CH3). Mass Spectrum (m/z, +ve ion mode): 421[M+ +1]. The following compounds were prepared similarly 4-(3-{[4-(3,4-Dimethyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl )tetrahydro-2//-pyran-4-carbonitrile (Compound No. 27), Yield: 60 mg, 'HNMR(300MHz, CDC13): 7.56 (s, 1H, Ar-H), 7.41-7.06 (m, 7H, Ar-H), 4.11-4.07 (m, 2H, -OCH2), 3.93-3.86 (m, 2H, -OCH2), 3.49 (s, 3H, -NCH3), 2.16 (s, 3H, Ar-CH3) and 2.13-2.03 (m, 4H, 2x-CH2), 4-(3-{[4-(4-Isopropyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 29), Yield: 100 mg, Mass Spectrum (m/z, +ve ion mode): 435 [M+ + 1], 4-(3-{[4-(3-Methyl-5-oxo-4-propyl-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 30), Yield: lOOmg, Mass Spectrum (m/z, +ve ion mode): 435 [M+ + 1], 4-(3-{[4-(4-Cyclohexyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 31), Yield: 80 mg, Mass Spectrum (m/z, +ve ion mode): 475 [M + 1], 4-(3.{[4.(4-ISobutyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2#-pyran-4-carbonitrile (Compound No. 32), Yield: 90 mg, Mass Spectrum (m/z, +ve ion mode): 449 [M+ +1], 4-(3-{[4-(4-Butyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 33), Yield: lOOmg, Mass Spectrum (m/z, +ve ion mode): 449 [M+ +1], 4-13-( {4-[4-(Cy clopropylmethyl)-3-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1 -yl]phenyl}thio)phenyl]tetrahydro-2/;/-pyran-4-carbonitrile (Compound No. 34), Yield: 95 mg, Mass Spectrum (m/z, +ve ion mode): 447 [M+ + 1], 4-|3-({4-[4-(Cyclohexylmethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio)phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 35), Yield: 80 mg, Mass Spectrum (m/z, +ve ion mode): 489 [M+ + 1], 4-(3- {[4-(4-Cyclopentyl-3-methyl-5-oxo-4,5-dihydro- \H-1,2,4-triazol-1 -yl)phenyl] thio}phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 36), Yield: 100 rng, Mass Spectrum (m/z, ^ve ion mode): 461[M+ + 1], 4-[3-({4-[4-(2-Chloroethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl} thio)phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 37), Yield: 80 mg, Mass Spectrum (m/z, +ve ion mode): 455 [M+ +1], 4-[3-({4-[4-(2-Hydroxyethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl} thio)phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 38), Yield: 80 mg, Mass Spectrum (m/z, ^ve ion mode): 437 [M+ + 1 j, 4-(3-{[4.(4-Allyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 39), Yield: 120 mg, Mass Spectrum (m/z, +ve ion mode): 433 [M +1], 4.[3-({4-[3-Methyl-4-(2-morpholin-4-ylethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio)phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 40), Yield: lOOmg, Mass Spectrum (m/z, +ve ion mode): 506 [M+ + 1], 4-[3-({4-[4-(Cyanomethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl} thio) phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 41), Yield: 90 mg, Mass Spectrum (m/z, +ve ion mode): 454 [M+ + 23], 4-( 3- {14-(4-Cycloheptyl-3-methy l-5-oxo-4,5-dihydro-1 H-1,2,4-triazol-1 -yl)phenyl] thio}phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 42), Yield: 50 mg, 'H NMR (300MHz, CDC13): 8 7.46-7.38 (m, 4H, Ar-H), 7.32-7.28 (m, 3H, Ar-H), 7.13-7.12 (m, 111, Ar-H), 4.10-4.05 (m, 2H, -OCH2), 3.93-3.84 (m, 2H, -OCH2), 3.07 (s, 3H, Ar-CH3), 2.97-2.90 (m, 1H, -NCH) and 2.12-1.64 (brm, 16H, 8x -CH2), The following compounds were prepared by following procedure of example 9 by using 4-(3- {[4-(5-oxo-4,5-dihydro-1H-1,2,4-triazol-1 -yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carbonitrile (example 8). 4-( 3- {[4-(4-Methy 1-5 -oxo-4,5 -dihydro-1 H-1,2,4-triazol-1 -yl)phenyl] thio} phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 43), Yield: 90 mg, Mass Spectrum (m/z, ±ve ion mode): 393 [M* + 1], 4-(3-{[4-(4-Ethyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 44), Yield: 85 mg, Mass Spectrum (m/z, +ve ion mode): 407 [M+ +1], 4-(3-{(4-(5-Oxo-4-propyl-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 45), Yield: 95 mg, 'H NMR (400 MHz, CDC13): 6 7.96 (s, 1H, Ar-H), 7.70-7.55 (m, 2H, Ar-H), 7.49-7.37 (m, 5H, Ar-H), 7.29-7.26 (m, 1H, Ar-H), 4.10-4.07 (m, 2H, -OCH2), 3.92-3.81 (m, 4H, -OCH2 & - NCH2), 2.11-2.05 (m, 4H, 2x-CH2), 1.86-1.80 (m, 2H, -CH2) and 0.98 (t, 3H, J=8.00 Hz, -CH3), Mass Spectrum (m/z, +ve ion mode): 421|M++1], 4-(3-{[4-(4-Isopropyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 46), Yield: 70 mg, Mass Spectrum (m/z, +ve ion mode): 421[M+ +1], 4-(3-{[4-(4-Butyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 47), Yield: 70 mg, Mass Spectrum (m/z, ±ve ion mode): 435 [M+ +1], 4_( 3. {[4-(4-lsobutyl-5 -oxo-4,5-dihydro-1 H-1,2,4-triazol-1 -yl)phenyl]thio} phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 48), Yield: 87 mg, Mass Spectrum (m/z, -\ ve ion mode): 435 [M+ + 1], 4-(3-{[4-(4-Cyclopropyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 49), Yield: 60 mg, Mass Spectrum (m/z, +ve ion mode): 419 [M+ +1], 4-|3-({4-[4-(Cyclopropylmethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio) phenyl] tetrahydro-2//-pyran~4-carbonitrile (Compound No. 50), Yield: 60 mg, Mass Spectrum (m/z, i ve ion mode): 433 [Mf + 1], 4-(3.{[4_(4-Cyclopentyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 51), Yield: 80 mg, *HNMR(400MHz, CDC13): 5 7.68 (s, IH, Ar-H), 7.56-7.54 (m, 2H, Ar-H), 7.49-7.46 (m, 6H, Ar-H), 4,70 (m, IH, -NCH), 4.10-4.06 (m, 2H, -OCH2), 3.92-3.85 (m, 2H, -OCH2), 2.10-2.02 (m, 6H, 3x-CH2) and 1.93-1.88 (brm, 6H, 3x-CH2), 4-(3- {[4-(4-Cyclohexy 1-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1 -yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 52), Yield: 95 mg, Mass Spectrum (m/z, ^ve ion mode): 461 [M+ + 1], 4-|3-({4-[4-(Cyclohexylmethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio) phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 53), Yield: 90 mg, Mass Spectrum (m/z, +ve ion mode): 475 [M+ +1], 4-(3- {[4-(4-Cyclohepty 1 -5-oxo-4,5-dihydro-1 H-1,2,4-triazol-1 -yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 54), Yield: 85 mg, Mass Spectrum (m/z, +ve ion mode): 475 [M+ + 1], 4-(3-{[4-(4-Allyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 55), Yield: 65 mg, Mass Spectrum (m/z, +ve ion mode): 419 [M+ +1], 4-(3-{[4-(5-Oxo-4-prop-2-yn-l-yl-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 56), Yield: 78 mg, Mass Spectrum (m/z, +ve ion mode): 417 [Mf + 1], 4-[3-({4-[4-(2-Hydroxyethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio) phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 57), Yield: 75 mg, Mass Spectrum (m/z, ^ve ion mode): 423 [M+ + 1]. Example 10: Synthesis of 4-(3-{[4-(4-ethvl-3-methvl-5-oxo-4.5-dihvdro-l//-1.2.4-triazol-l-yl)phenyl]thio}phenvl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 1) Solid potassium hydroxide (0.035 g, 0.6333 mmol) was added to a solution of 4-(3-{[4-(4-ethyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl )tetrahydro-2//-pyran-4-carbonitrile (0.070 g, 0.166 mmol) (example 9) in isopropyl alcohol and methanol mixture (3 ml). The reaction mixture was heated at about 90-100° C for about 12-15 hours. The solvent was evaporated under vacuum and water was added. A white solid separated out, which was filtered and dried under vacuum to afford the title compound. Yield: 0.045 g. 'HNMR (300 MHz, CDC13): 5 7.40-7.29 (m, 10H, Ar-H & 2 x -NH), 3.88-3.75 (m, 6H, 2 x -OCH2 & -NCH2), 2.36-2.32 (m, 2H, -CH2), 2.16 (s, 3H, Ar-CH3), 2.10-2.05 (m, 2H,-CH2) and 1.37(t, 3H,J=6.0Hz,-CH3). Mass Spectrum (m/z, + ve ion mode) : 439 [M+ + 1] The following compounds were prepared similarly : 4-(3-{[4-(4-Isobutyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 2), Yield: 55 mg. Mass Spectrum (m/z, +ve ion mode): 467 [M+ +1], 4-(3-{[4-(4-Cyclopentyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 3), Yield: 40 mg, Mass Spectrum (m/z, +ve ion mode): 479 [M+ +1], 4-(3 - {[4-(3-Methy l-5-oxo-4-propyl-4,5-dihydro-1H-1,2,4-triazol-1 -yl)phen)d]thio} phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 4), Yield: 40 mg, Mass Spectrum (m/z, +ve ion mode) :453 [M+ +1], 4-(3-{[4-(4-Isopropyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 5), Yield: 40 mg, Mass Spectrum (m/z, +ve ion mode): 453 [M+ + 1], 4-(3-{[4-(4-Butyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 6), Yield: 40 mg, Mass Spectrum (m/z, +ve ion mode): 467 [M+ + 1], 4-(3-{[4-(4-Allyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro~2//-pyran-4-carboxamide (Compound No. 8), Yield: 30 mg, Mass Spectrum (m/z, +ve ion mode): 451[M+ +1], 4-|f3.({4.[3-Methyl-4-(2-morpholin-4-ylethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yljphenyl}thio)phenyl]tetrahydro-2//-pyran-4-carboxamide (Compound No. 9), Yield: 40 mg, Mass Spectrum (m/z, +ve ion mode): 524 [M+ +1], 4.[3.({4_[4.(2-Chloroethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl} thio)phenyl]tetrahydro-2//-pyran-4-carboxamide (Compound No. 10), Yield: 12mg, Mass Spectrum (m/z, +ve ion mode): 473 [M+ +1], 4-[3-({4-[4-(Cyclohexylmethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio)phenyl]tetrahydro-2//-pyran-4-carboxamide (Compound No. 11), Yield: 40 mg. Mass Spectrum (m/z, +ve ion mode): 507 [M+ + 1], 4-[3-({4-[4-(2-Hydroxyethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio)phenyl]tetrahydro-2//-pyran-4-carboxamide(CompoundNo. 12), Yield: 10 mg, ass Spectrum (m/z, +ve ion mode): 455 [M+ +1], 4-(3-{[4-(4-Cyclohexyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 13), Yield: 10 mg, Mass Spectrum (m/z, +ve ion mode): 493 [M+ + 1], 4-(3-{[4-(4-Methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 14), Yield: 30 mg, Mass Spectrum (m/z, +ve ion mode): 411[M+ + 1], 4-( 3 - {[4-(4-Ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1 -yl)phenyl]thio} phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 15), Yield: 32 mg, Mass Spectrum (m/z, ±ve ion mode): 425 [M"1" + 1], 4-(3-{[4-(5-Oxo-4-propyl-4,5-dihydro-lW-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 16), Yield: 30 mg, 'H NMR (400 MHz, CDC13+CD3OD):8 8.12 (s, 1H, Ar-H), 7.5-7.14 (m, 8H, Ar-H), 7.14 (brs, 1H, -NH), 3.85-3.81 (m, 4H, 2x-OCH2), 3.75-3.70 (m, 2H, -NCH2), 2.42-2.39 (m, 2H, -CH2), 2.07-2.00 (m, 2H, -CH2), 1.88-1.79 (m, 2H, -CH2) and 0.99 (t, 3H, J=8.00Hz, -CH3), Mass Spectrum (m/z, +ve ion mode): 439 [M^+l], 4-[3-({4-[4-(Cyclopropylmethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio) phenyl]tetrahydro-2//-pyran-4-carboxamide (Compound No. 17), Yield: 30 mg, Mass Spectrum(w/z, +ve ion mode): 451 [M+ +1], 4-(3-{[4-(4-lsopropyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 18), Yield: 30 mg, Mass Spectrum (m/z, +ve ion mode): 439 [M+ + 1], 4-(3-{[4-(4-Butyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 19), Yield: 33 mg, Mass Spectrum (m/z, +ve ion mode): 453 [M+ +1], 4-(3-{[4-(4-Cyclopentyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 20), Yield: 25 mg, Mass Spectrum (m/z, +ve ion mode): 465 [M+ +1], 4-(3-{[4-(4-Isobutyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 21), Yield: 35 mg, Mass Spectrum (m/z, +ve ion mode): 453 [M+ + 1], 4-(3-{[4-(4-Cyclohexyl-5-oxo-4,5-dihydro-17/-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 22), Yield: 15mg, Mass Spectrum (m/z, +ve ion mode): 479 [M+ +1], 4-[3-({4-[4-(Cyclohexylmethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio) phenyl]tetrahydro-2//-pyran-4-carboxamide (Compound No. 23), Yield: 27 mg, Mass Spectrum (m/z, +ve ion mode): 493 [M+ +1], 4-(3-{[4-(4-Cycloheptyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 24), Yield: 23 mg, Mass Spectrum (m/z, +ve ion mode): 493 [M+ +1], 4-(3-{[4-(4-Allyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 25), Yield: 32 mg, Mass Spectrum (m/z, + ve ion mode): 437 [M+ + 1], 4- [ 3 -({4- [4-(2-Hydroxyethyl )-5 -oxo-4,5 -dihydro-1H-1,2,4-triazol-1 -yl]phenyl} thio) phenyl]tetrahydro-2//-pyran-4-carboxamide (Compound No. 26), Yield: 30 mg, Mass Spectrum (m/z, +ve ion mode): 441[M+ +1]. The following compound was prepared by following the procedure of example 10 by using 4-(3- {[4-(3-methyl-5-oxo-4,5-dihydro-l#- 1,2,4-triazol-l-yl) phenyl] thio}phenyl)tetrahydro-2//- pyran-4-carbonitrile (example 7). 4-(3-{[4-(3-Methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 7), Yield: 30 mg, Mass Spectrum (m/z, +ve ion mode): 411 [M++l]. Example 11: Synthesis of Ar-[(l£')-(dimethylaniino)niethylene]-4-(3-{[4-(3-methvl-5-oxo-4,5- dihydro-l//-l,2.4-triazol-l-yl)phenvl]thio}phenvls)tetrahvdro-2//-pyran-4-carboxamide AfW-Dimethylformamide dimethyl acetal (15 ml) was added to 4-(3-{[4-(3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyrjthio}phenyl)tetrahydro-2//-pyran-4-carboxamide (2.0 g, 4.88 mmol) (example 10) and the reaction mixture was refluxed for about 2 hours. The solvent was evaporated under reduced pressure to obtain a light brown paste. Yield: 3.0 g. The following compound was prepared similarly by using ./V.jV-dimethylacetamide dimethyl acetal. A4( 1E)-1 -(Dimethylamino)ethylidene]-4-(3- {[4-(3-methyl-5-oxo-4,5-dihydro-1 //-1,2,4-triazol-1 -yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxamide Yield: 1.20g. Example 12: Synthesis of 5-methvl-2-[4-((3-[4-(4//-1.2.4-triazol-3-vl)tetrahvdro-2//-pvran-4-Yl]phenyl|thio)phenyl]-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 68) Hydrazine dihydrochloride (1.13 g, 10.75 mmol) in sodium hydroxide solution (5N, 3 ml) was added to a solution of A^-[(l£')-(dimethylamino)methylene]-4-(3-{[4-(3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxamide (3.0 g, 2. 1 5 mmol) (example 1 1) in 1 ,4-dioxane. Glacial acetic acid (30 ml, 70%) was added to it and the reaction mixture was stirred at room temperature for about 30 minutes and then at 90° C for about 5 hours. The solvent was evaporated under vacuum and a saturated solution of sodium bicarbonate was added till the solution became basic . The reaction mixture was extracted with ethyl acetate, washed with water, dried over anhydrous sodium sulphate, filtered and the solvent evaporated under vacuum to afford a thick oily residue, which upon column chromatography over silica gel using methanol and ethyl acetate (1:19) afforded the title compound as white crystalline solid. Yield: l.lOg 'H NMR (400 MHz, CDC13): 5 10.55 (s, 1H, -NH), 8.23 (s, 1H, Ar-H), 7.40-7.34 (m, 4H, Ar-H), 7.29-7.18 (m, 4H, Ar-H), 6.58 (s, 1H, -NH), 3.91-3.89 (m, 2H, -OCH2), 3.51-3.46 (m, 2H, -OCH2), 2.60-2.57 (m, 2H, -CH2), 2.27-2.20 (m, 2H, -OCH2) and 2.06 (s, 3H, Ar-CH3). Mass Spectrum (m/z, +ve ion mode): 435 [M++l] Example 13: Synthesis of 4,5-dimethvl-2-f4-('{3-r4-(3-methvl-1.2.4-oxadiazol-5-vntetrahvdro-2//-pvran-4-yl]phenyl}thio)phenyl] -2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 69) A solution of hydroxylamine hydrochloride (0.522 g, 7.52 mmol) in sodium hydroxide (1M, 10 ml) was added to A'-[(l£)-l-(dimethylamino)ethylidene]-4-(3-{[4-(3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxamide (1 .20 g, 2.51 mmol) (example 1 1). It was then diluted with 1,4-dioxane (7.5 ml) followed by glacial acetic acid (10 ml) and the reaction mixture stirred for about 30 minutes at room temperature. The mixture was then heated at 90° C for about 10 hours. The solvent was evaporated under vacuum and a saturated solution of potassium carbonate was added till the solution became basic. The reaction mixture was extracted with ethyl acetate, washed with water, dried over anhydrous sodium sulphate, filtered and the solvent evaporated under vacuum to afford a thick oily residue which upon column chromatography over silica gel using ethyl acetate and hexane (4:1) gave the title compound as a thick oil. Yield: 0.60 g 'H NMR (300 MHz, CDC13):8 7.45 (s, 1H, Ar-H), 7.35-7.31 (m, 6H, Ar-H), 7.22-7.19 (m, 1H, Ar-H), 3.99-3.95 (m, 2H, -OCH2), 3.68-3.51 (m, 2H, -OCH2), 3.48 (s, 3H, Ar-CH3), 2.73-2.68 (m, 2H, -CH2), 2.31 (s, 3H, Ar-CH3), 2.30-.2.21 (m, 2H, -CH2) and 2.15 (s, 3H, Ar-CH3). Mass Spectrum (m/z, ±ve ion mode): 464 [M++l] Example 14: Synthesis of 5-methyl-4-propyl-2-[4-((3-[4-(4-propvl-4//-l,2,4-triazol-3-vl)tetrahvdro-2//-pvran-4-yl]phenvlUhio)phenyl]-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound Solid potassium carbonate (0.127 g, 0.9216 mmol) was added to a solution of 5-methyl-2-[4-({3-[4-(4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio) phenyl]-2,4-dihydro-3//-l,2,4-triazol-3-one (0.100 g, 0.2304 mmol) (example 12) in dry dimethylformamide (3 ml). The reaction mixture was stirred at room temperature for about 5 minutes. jV-Propyl bromide (0.113 g, 0.9216 mmol) was added to it and the mixture was heated at 90°-100° C for about 12 hours. The solvent was evaporated under vacuum, water was added to it and the mixture was extracted with ethyl acetate. The organic layer was washed with water, dried over anhydrous sodium sulphate, filtered and the solvent evaporated under vacuum to afford an oily residue. The product was purified by preparative thin layer chromatography using ethyl acetate and hexane (1:1) as the eluant to get the title compound as white solid. Yield: 70 mg. 'H NMR (CDC13, 400 MHz): 8 8.08 (s, 1 H, Ar-H), 7.42-7.16 (m, 8 H, Ar-H), 4.10-4.07 (t, 2 H, J=7.00 Hz, -NCH2), 3.90-3.78 (m, 2 H, -OCH2), 3.76-3.74 (m, 4 H, -OCH2 & -NCH2), 2.68 (m, 2 H, -CH2), 2.16-2.14 (m, 5 H, -CH2 & Ar-CH3), 1.89-1.78 (m, 4 H, 2 x -CH2), 0.97 (t, 3H, J=8.00 Hz, -CH3) and 0.89 (t, 3 H, J=8.00 Hz, -CH3). Mass Spectrum (m/z, +ve ion mode): 519 [M+ +1]. The following compounds were prepared similarly 4,5-Dimethyl-2-[4-({3-[4-(4-methyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 58), Mass Spectrum (m/z, +ve ion mode): 463 [M +1], 4-Ethyl-2-[4-({3-[4-(4-ethyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 59), Mass Spectrum (m/z, +ve ion mode): 491[M+ +1], 4-lsopropyl-2-[4-({3-[4-(4-isopropyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 61), Mass Spectrum (m/z, +ve ion mode): 519 [M+ + 1], 4-Butyl-2-[4-({3-[4-(4-butyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl] phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 62), Mass Spectrum (m/z, +ve ion mode): 547 [M+ +1], 4-lsobutyl-2-[4-({3-[4-(4-isobutyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 63), Mass Spectrum (m/z, +ve ion mode): 547 [M+ + 1], 4-Cyclopentyl-2-[4-({3-[4-(4-cyclopentyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 64), Mass Spectrum (m/z, +ve ion mode): 571 [M+ +1], 4-Cyclohexyl-2-[4-({3-[4-(4-cyclohexyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 65), Mass Spectrum (m/z, +ve ion mode) : 599 [M+ + 1], 4-Cycloheptyl-2-[4-({3-[4-(4-cycloheptyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yljphenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 66 ), Mass Spectrum (m/z, +ve ion mode) : 627 [M+ +1], 4-Allyl-2-[4-({3-[4-(4-allyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 67 ), Mass Spectrum (m/z, ±ve ion mode}: 515 [M+ + 1]. Example 15: Synthesis of 4-(3-U4-(3-methvl-5-oxo-4.5-dihvdro-l//-1.2.4-triazol-l-vl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxvlicacid Potassium hydroxide (3.0 mmol) is added to a solution of 4-(3-{[4-(3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (1.0 mmol) (example 10) in methanol and tetrahydrofuran (1:2) and the reaction mixture is refluxed for about 18 hours. The solvent is evaporated under vaccum. A small amount of water and concentrated hydrochloric acid are added to the residue to separate out the title compound. Example 16: Synthesis of 4-(3-l[4-(3-methyl-5-oxo-4,5-dihvdro-l//-1.2.4-triazol-l-yl)phenyl]thio}phenvl)-Ar-prop-2-vn-l-vltetrahvdro-2//-pvran-4-carboxamide l-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI. HC1) (1.0 mmol) is added to a mixture of 4-(3-{[4-(3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol -1-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxylic acid (1.0 mmmol) (example 15), 1-hydroxybenzotriazole (1.0 mmol), A/-methylmorpholine (1.65 mmol) and propargylamine (1.0 mmol) in dichloromethane-dimethylformamide (1:1) at 0° C. The solution is stirred overnight at room temperature, washed with water and the aqueous layer is extracted with dichloromethane. The combined organic extracts are dried with sodium sulphate, filtered and the solvent is evaporated under reduced pressure. The residue is purified by column chromatography over silica gel to yield the title product. Example 17: Synthesis of 5-methvl-2-f4-(l3-r4-(5-methvl-l,3-oxazol-2-yl)tetrahvdro-2//-pvran-4-yl]phenvl}thio)phenyl]-2,4-dihydro-3//-1,2,4-triazol-3-one (Compound No.70) A solution of 4-(3-{[4-(3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl] thio}phenyl)-A/-prop-2-yn-l-yltetrahydro-2//-pyran-4-carboxamide (1.0 mmol) (example 16) and mercuric acetate (0.11 mmol) in acetic acid is heated at reflux for about 3 hours. All the volatiles are removed under reduced pressure and an aqueous solution of saturated potassium carbonate is added to the residue. The mixture is then extracted with dichloromethane, and the organic layer is dried over anhydrous sodium sulphate, filtered and concentrated under reduced pressure. The residue is then purified by column chromatography over silica gel to yield the title compound. Example 18: Synthesis of 4,5-dimethyl-2-[4-('(3-r4-(5-methvl-1.3-oxazol-2-vl)tetrahvdro-2//-pyran-4-yl]phenvl}thio)phenyl]-2,4-dihydro-3//-l,2,4-triazol-3-one Compound No.71) Solid potassium carbonate (4.5.mmol) is added to a solution of 5-methyl-2-[4-({3-[4-(5-methyl-l,3-oxazol-2-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-2,4-dihydro-3//-l,2,4-triazol-3-one (1.0 mmol) (example 17) in dry dimethylformamide. The reaction mixture is stirred a room temperature for about 15 minutes. Methyl iodide (3.0 mmol) is added to it and the reaction mixture is heated at about 100° C for about 12 hours. The solvent is evaporated under vaccum, water is added and the reaction mixture is extracted with ethyl acetate. The organic layer is washed with water, dried over anhydrous sodium sulphate, filtered and the solvent is evaporated to afford the residue. Column chromatography of the residue over silica gel affords the title compound. Example 19: Synthesis of ethvl 4-(3-([4-(3-methvl-5-oxo-4.5-dihvdro-l//-1.2.4-triazol-l-vl)phenyl]thio}phenyl)tetrahvdro-2^-pvran-4-carboxylate Ethanol is added to a solution of 4-(3-{[4-(3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxylic acid (1.0 mmol) (example 15) and the reaction mixture is cooled to 0° C. The contents are stirred for about 15 minutes. Thionyl chloride (1.2 mmol) is added dropwise at 0° C and the reaction mixture is stirred at room temperature for about 2 hours. The solvent is evaporated under vaccum, dichloromethane is added and the contents are washed with a cold solution of sodium bicarbonate. The organic layer is dried over sodium sulphate, filtered and the solvent is evaporated to afford the title compound. Example 20: Synthesis of Af-(2-hvdroxvethvl)-4-(3-([4-(3-methvl-5-oxo-4.5-dihvdro-l//-l,2.4-triazol-l-yl)phenyl]thio}phenyl)tetrahvdro-2//-pyran-4-carboxamide 2-Ethanolamine (6.0 mmol) is added to a solution of ethyl 4-(3-{[4-(3-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1 -yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxylate (1.0 mmol) (example 19) in ethanol and the contents are refluxed. All the volatiles are removed under reduced pressure and the residue is purified by column chromatography over silica gel to afford the title compound. Example 21: Synthesis of 2-[4-({3-|4-(4.5-dimethvl-4.5-dihvdro-1.3-oxazol-2-yl)tetrahvdro-2//-pyran-4-yl]phenyUthio)phenyl]-5-methvl-2.4-dihydro-3//-1,2.4-triazol-3-one (Compound No. 72) Triethylamine (5.0 mmol) and carbon tetrachloride (5.0 mmol) are added dropwise to a solution of Ar-(2-hydroxyethyl)-4-(3-{[4-(3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl)tetrahydro-2//-pyran-4-carboxamide (1.0 mmol) (example 20) in acetonitrile. The reaction mixture is stirred at room temperature for about 3 hours. The solution is filtered and the filtrate is concentrated under reduced pressure to afford the residue. Column chromatography of the residue over silica gel affords the title compound. Example 22: Synthesis of 2-[4-((3-{4-(4.5-dimethvl-4.5-dihvdro-1.3-oxazol-2-vl)tetrahvdro-2//-pvran-4-vl1phenvl)thio)phenvl1-4.5-dimethvl-2.4-dihvdro-3/f-1.2.4-triazol-3-one (Compound No. 73} Solid potassium carbonate (4.5 mmol) is added to a solution of 2-[4-({3-[4-(4,5-dimethyl-4,5-dihydro-l,3-oxazol-2-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (1.0 mmol) (example 21) in dry dimethylformamide. The reaction mixture is stirred a room temperature for about 15 minutes. Methyl iodide (3.0 mmol) is added to it and the reaction mixture is heated at about 100° C for about 12 hours. The solvent is evaporated under vaccum, water is added and the reaction mixture is extracted with ethyl acetate. The organic layer is washed with water, dried over anhydrous sodium sulphate, filtered and the solvent is evaporated to afford the residue. Column chromatography of the residue over silica gel affords the title compound, Example 23 : Efficacy of compounds as S-Lipoxygenase inhibitors 5-Lipoxygenase enzyme inhibition Assay was carried out in 96 well UV plate containing 100 uL reaction mixture 1,4-dithiothreitol (DTT) 200 uM; adenosine triphosphate (ATP), 100 uM; and calcium chloride, 100 ^M; in phosphate buffered saline in the absence and presence of different concentrations of test compound (10 nM-10 uM) and 12 U (3 U ul"1) of human recombinant 5-lipoxygenase (Cayman Chemicals Co., USA). The reaction mixture was incubated at 37° C for 5 min, and reaction initiated by adding 1 ul of 1 mM freshly prepared arachidonic acid. Increase in absorbance was monitored at 234 nm for 10 minutes. (J. Biol. Chem., 261, 11512-11519, 1986). A plot of absorbance vs. time curve was prepared and area under curve (AUC) was computed for each well. Percent inhibition of AUC for different treatments was calculated with respect to the difference between the arachidonic acid stimulated and negative control values, to compute IC50 values. The assay was repeated with the same protocol in the absence of DTT to mimic non-reducing condition and ICso values were computed. IC50 values for some of the compounds was found to be in the range of low nM to >10uM. Cell based assay: A23187 induced LTB4 release Neutrophils were isolated from freshly drawn human blood after dextran sedimentation and ficoll separation (Eur. J. Biochem., 169, 175, 1987). Neutrophil suspension (0.2xl06 cells/ml) was incubated in polystyrene microtitre plates with test compound in a 24 well plate and incubated at 37° C for Ihr. and 0.25 mM Ca++/Mg++ was added in the final 3 min of incubation period. The reaction was initiated by adding 0.3 ug ml"1 A23187 (Sigma-Aldrich Co, USA) and continued for 10 min at 37° C. The reaction was stopped by adding 80 uL of cold methanol (J. Pharmacol. Exp. Ther. 297, 267, 2001). The samples were analysed for LTB4 assay using LTB4 ELISA kits. The amount of LTB4 released was quantified and percent inhibition of LTB4 release was calculated with respect to the difference between the A23187 stimulated and negative control cells, to compute ICso values. 1C50 values for some of the compounds was found to be in the range of low nM to >10uM. We claim: 1. Compounds having the structure of Formula I: (Figure Removed) and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates, stereoisomers, tautomers, racemates, regioisomers, prodrugs, metabolites, polymorphs or jV-oxides, wherein G represents O or S, Z represents -(CHiVX- or -X-(CH2)n-, X represents -NRi, -O- or -S-, n represents an integer in the range of 0-2, R\ represents hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl, R2 represents -CN, -CORs, 5-membered heteroaryl or hetereocyclyl, RS represents hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl, -ORj, -SRj or -N(Ri)2. 2. Compounds, which are - 4-(3-{[4-(4-Ethyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 1), - 4-(3-{[4-(4-lsobutyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 2), - 4-(3-{[4-(4-Cyclopentyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 3), - 4-(3-{[4-(3-Methyl-5-oxo-4-propyl-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2#-pyran-4-carboxamide (Compound No. 4), - 4-(3-{[4-(4-Isopropyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 5), - 4-(3-{[4-(4-Butyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 6), - 4-(3 - {[4-(3 -Methyl-5 -oxo-4,5 -dihydro-1H-1,2,4-triazol-1 -yl)phenyl]thio} phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 7), - 4-(3-{[4-(4-Allyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 8), - 4-[3-({4-[3-Methyl-4-(2-morpholin-4-ylethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l- yl]phenyl}thio)phenyl]tetrahydro-2//-pyran-4-carboxamide (Compound No. 9), - 4-[3-({4-[4-(2-Chloroethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l- yl]phenyl}thio)phenyl]tetrahydro-2/ir-pyran-4-carboxamide (Compound No. 10), 4-[3-({4-[4-(Cyclohexylmethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio)phenyl]tetrahydro-2//-pyran-4-carboxamide (Compound No. 11), 4-[3-({4-[4-(2-Hydroxyethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio)phenyl]tetrahydro-2//-pyran-4-carboxamide (Compound No. 12), 4-(3-{[4-(4-Cyclohexyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carboxamide (Compound No. 13), 4-(3-{[4-(4-Methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro~2/7-pyran-4-carboxamide (Compound No. 14), 4-(3-{[4-(4-Ethyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 15), 4-(3-{[4-(5-Oxo-4-propyl-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2/Y-pyran-4-carboxamide (Compound No. 16), 4-[3-({4-[4-(Cyclopropylmethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio) phenyl]tetrahydro-2//-pyran-4-carboxamide (Compound No. 17), 4-(3-{[4-(4-lsopropyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 18), 4-(3-{[4-(4-Butyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 19), 4-(3-{[4-(4-Cyclopentyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 20), 4-(3-{[4-(4-lsobutyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 21), 4-(3-{[4-(4-Cyclohexyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2f/-pyran-4-carboxamide (Compound No. 22), 4-[3-({4-[4-(Cyclohexylmethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio) phenyl]tetrahydro-2//-pyran-4-carboxamide (Compound No. 23), 4-(3-{[4-(4-Cycloheptyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2f/-pyran-4-carboxamide (Compound No. 24), 4-(3-{[4-(4-Allyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carboxamide (Compound No. 25), 4-[3-({4-[4-(2-Hydroxyethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio) phenyl]tetrahydro-2//-pyran-4-carboxamide (Compound No. 26), 4-(3 - {[4-(3,4-Dimethy 1-5 -oxo-4,5 -dihydro-1H-1,2,4-triazol-1 -yl)phenyl] thio} phenyl )tetrahydro-2//-pyran-4-carbonitrile (Compound No. 27), 4-(3-{[4-(4-Ethyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl )tetrahydro-2//-pyran-4-carbonitrile (Compound No. 28), 4-(3- {[4-(4-lsopropyl-3-methyl-5-oxo-4,5 -dihydro-1 H-1,2,4-triazol-1 -yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 29), 4-(3-{[4-(3-Methyl-5-oxo-4-propyl-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 30), 4-(3-{[4-(4-Cyclohexyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 31), 4-(3-{[4-(4-lsobutyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 32), 4-(3-{[4-(4-Butyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 33), 4-[3-({4-[4-(Cyclopropylmethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio)phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 34), 4-[3-({4-[4-(Cyclohexylmethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio)phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 35), 4-(3-{[4-(4-Cyclopentyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl] thio}phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 36), 4-[3-({4-[4-(2-Chloroethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio)phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 37), 4-[3-({4-[4-(2-Hydroxyethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio)phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 38), 4-(3-{[4-(4-Allyl-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio} phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 39), 4-[3-({4-[3-Methyl-4-(2-morpholin-4-ylethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio)phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 40), 4-[3-({4-[4-(Cyanomethyl)-3-methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl} thio)phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 41), 4-(3 - {[4-(4-Cycloheptyl-3 -methyl-5 -oxo-4,5 -dihydro-1H-1,2,4-triazol-1 -yl)phenyl] thio}phenyl)tetrahydro-2//-pyran-4-carbonitrile (Compound No. 42), 4-(3-{[4-(4-Methyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 43), 4-(3-{[4-(4-Ethyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 44), 4-(3-{[4-(5-t)xo-4-propyl-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 45), 4-(3-{[4-(4-lsopropyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 46), 4-(3-{[4-(4-Butyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 47), 4-(3-{[4-(4-Isobutyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 48), 4-(3- {[4-(4-Cyclopropyl-5-oxo-4,5-dihydro-1 H-1,2,4-triazol-1 -yl)phenyl]thio} phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 49), 4-[3-({4-[4-(Cyclopropylmethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio) phenyl] tetrahydro-2//-pyran-4-carbonitrile (Compound No. 50), 4-(3-{[4-(4-Cyclopentyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 51), 4-(3-{[4-(4-Cyclohexyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2f/-pyran-4-carbonitrile (Compound No. 52), 4-[3-({4-[4-(Cyclohexylmethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio) phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 53), 4-(3-{[4-(4-Cycloheptyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 54), 4-(3-{[4-(4-Allyl-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 55), 4-(3-{[4-(5-Oxo-4-prop-2-yn-l-yl-4,5-dihydro-l//-l,2,4-triazol-l-yl)phenyl]thio}phenyl) tetrahydro-2//-pyran-4-carbonitrile (Compound No. 56), 4-[3-({4-f4-(2-Hydroxyethyl)-5-oxo-4,5-dihydro-l//-l,2,4-triazol-l-yl]phenyl}thio) phenyl]tetrahydro-2//-pyran-4-carbonitrile (Compound No. 57), 4,5-Dimethyl-2-[4-({3-[4-(4-methyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 58), 4-Ethyl-2-[4-({3-[4-(4-ethyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 59), 5-Methyl-4-propyl-2-l4-({3-[4-(4-propyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 60), 4-Isopropyl-2-[4-({3-[4-(4-isopropyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (CompoundNo. 61), 4-Butyl-2-[4-({3-[4-(4-butyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl} thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 62), 4-Isobutyl-2-[4-({3-[4-(4-isobutyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 63), 4-Cyclopentyl-2-[4-( {3-[4-(4-cyclopentyl-4//-1,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 64), 4-Cyclohexyl-2-[4-({3-[4-(4-cyclohexyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl] phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 65), 4-Cycloheptyl-2-[4-({3-[4-(4-cycloheptyl-4//-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 66), 4-Allyl-2-l4-({3-[4-(4-allyl-4f/-l,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio) phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 67), 5-Methyl-2-14-( {3-[4-(4//-1,2,4-triazol-3-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio) phenyl]-2,4-dihydro-3//-l,2,4-triazol-3-one (CompoundNo. 68), 4,5-Dimethyl-2-[4-({3-[4-(3-methyl-l,2,4-oxadiazol-5-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 69), 5-Methyl-2-(4-({3-[4-(5-methyl-l,3-oxazol-2-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio) phenyl]-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 70), 4,5-Dimethyl-2-[4-({3-[4-(5-methyl-l,3-oxazol-2-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 71), 2-[4-({3-[4-(4,5-Dimethyl-4,5-dihydro-l,3-oxazol-2-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-5-methyl-2,4-dihydro-3//-l,2,4-triazol-3-one (CompoundNo. 72), 2-[4-({3-[4-(4,5-Dimethyl-4,5-dihydro-l,3-oxazol-2-yl)tetrahydro-2//-pyran-4-yl]phenyl}thio)phenyl]-4,5-dimethyl-2,4-dihydro-3//-l,2,4-triazol-3-one (Compound No. 73), and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates, stereoisomers, tautomers, racemates, regioisomers, prodrugs, metabolites, polymorphs or /V-oxides. 3. Pharmaceutical compositions comprising a therapeutically effective amount of compounds of claim 1, together with at least one pharmaceutically acceptable carrier, excipient or diluent. 4. Pharmaceutical compositions comprising a therapeutically effective amount of a compound of claim 1 and at least one other active ingredient selected from muscarinic receptor antagonists, PDE4 inhibitors/PDE3/4 inhibitors/PDE4B inhibitors/PDE? inhibitors, MMP9/12 inhibitors, caspase-1 inhibitors, beta 2 adrenoreceptor agonists, corticosteroids, p38 mitogen activated protein kinases, nuclear factor kappa B inhibitors, I kappa kinase inhibitors, VLA4 antagonists, thromboxane A2 antagonists, COX inhibitors, neutrophil elastase inhibitors, tachykinin receptor antagonists, secretory leukoprotease inhibitors, prostaglandin E analogues, adhesion molecule inhibitors, lipoxin agonists, tumour necrosis factor (TNF) inhibitors and other inflammatory cytokine inhibitors, chemokine inhibitors and chemokine receptor inhibitors, adenosine receptor antagonists, platelet activating factor antagonists, histamine release inhibitors, histamine receptor antagonists, nitric oxide synthase inhibitors, neurokinin antagonists and syk tyrosine kinase inhibitors. 5. Use of a therapeutically effective amount of a compound of claim 1 in the manufacture of a medicament for treating or preventing inflammatory and autoimmune diseases, in a patient. 6. Use of a therapeutically effective amount of a compound of claim 1 in the manufacture of a medicament for treating or preventing bronchial asthma, chronic obstructive pulmonary disorder, arthritis, type I diabetes, multiple sclerosis, allograft rejection, psoriasis, inflammatory bowel disease, ulcerative colitis, acne, atherosclerosis, cancer, pruritis, urticaria, atopic dermatitis, allergic rhinitis, in a patient. 7. Use of a therapeutically effective amount of pharmaceutical compositions of claim 3 and claim 4 in the manufacture of a medicament for treating or preventing inflammatory and autoimmune diseases, in a patient. 8. Use of a therapeutically effective amount of pharmaceutical compositions of claim 3 and claim 4 in the manufacture of a medicament for treating or preventing bronchial asthma, chronic obstructive pulmonary disorder, arthritis, type I diabetes, multiple sclerosis, allograft rejection, psoriasis, inflammatory bowel disease, ulcerative colitis, acne, atherosclerosis, cancer, pruritis, urticaria, atopic dermatitis, allergic rhinitis, in a patient. 9. A method for the preparation of compounds of Formula XVI, and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates, stereoisomers, tautomers, racemates, regioisomers, prodrugs, metabolites, polymorphs or N-oxides, wherein Z is -(CH2)n-X- or -X-(CH2)n-, X is -NRi, -O- or -S-, n is an integer in the range of 0-2, RI is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl and RI' is alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl), the method comprising (i) coupling compounds of Formula [I with ammonium carbonate to give compounds of,^ (ii) dehydration of the compounds of Formula III to give compounds of Formula IV, Formula IV reacting the compounds of Formula IV with compounds of Formula V (wherein Xi is halogen) to give compounds of Formula VI, reacting the compounds of Formula VI with compounds of Formula VII to give compounds of Formula VIII, (V)reacting the compounds of Formula VIII with compounds of Formula IX (wherein is halogen) to give compounds of Formula X (wherein Ar is aryl), (vi) reacting the compounds of Formula X with hydrazine to give compounds of Formula XI,(vii) reacting the compounds of Formula XI with compounds of Formula XII to give compounds of Formula XIII, (viii) reacting the compounds of Formula XIII with compounds of Formula XIV (wherein Xi is halogen) to give compounds of Formula XV, (ix) 10.and hydrolyzing the compounds of Formula XV to give compounds of Formula XVI. A method for the preparation of compounds of Formula XVII,(i)and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates, stereoisomers, tautomers, racemates, regioisomers, prodrugs, metabolites, polymorphs or jV-oxides, wherein Z is -(CHiVX- or -X-(CH2)n-, X is -NR], -O- or -S-, n is an integer in the range of 0-2 and RI is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralky], heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl, the method comprising coupling compounds of Formula II with ammonium carbonate to give compounds of Formula III (wherein X| is halogen), (ii) dehydration of the compounds of Formula III to give compounds of Formula IV, reacting the compounds of Formula IV with compounds of Formula V (wherein halogen) to give compounds of Formula VI,sFormula V Formula VI reacting the compounds of Formula VI with compounds of Formula VII to give compounds of Formula VIII, (V) reacting the compounds of Formula VIII with compounds of Formula IX (wherein X| is halogen) to give compounds of Formula X (wherein Ar is aryl), (vi) reacting the compounds of Formula X with hydrazine to give compounds of Formula XI, (vii) reacting the compounds of Formula XI with compounds of Formula XII to give compounds of Formula XIII, (viii ) hydrolyzing the compounds of Formula XIII to give compounds of Formula XVII. 11. A method for the preparation of compounds of Formula XXI, and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates, stereoisomers, tautomers, racemates, regioisomers, prodrugs, metabolites, polymorphs or TV-oxides, wherein Z is -(CHaVX- or -X-(CH2)n-, X is -NR], -O- or -S-, n is an integer in the range of 0-2, RI is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl, RI' is alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl) and R4 is hydrogen or alkyl, the method comprising (i) reacting compounds of Formula XVII with compounds of Formula XVIII to give compounds of Formula XIX (wherein RS is alkyl), (ii) reacting the compounds of Formula XIX with hydroxylamine to give compounds of Formula XX, (Hi) and reacting the compounds of Formula XX with compounds of Formula XIV (wherein Xi is halogen) to give compounds of Formula XXI. 12. A method for the preparation of compounds of Formula XXIII, and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates, stereoisomers, tautomers, racemates, regioisomers, prodrugs, metabolites, polymorphs or W-oxides, wherein Z is -(CHaVX- or -X-(CH2)n-, X is -NRi, -O- or -S-, n is an integer in the range of 0-2, RI is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl, RI' is alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl) and R4 is hydrogen or alkyl, the method comprising reacting compounds of Formula XVII with compounds of Formula XVIII to give compounds of Formula XIX (wherein RS is alkyl), (ii) reacting the compounds of Formula XIX with hydrazine to give compounds of Formula to give compounds of Formula XXIII. 13. A method for the preparation of compounds of Formula XXVIII, and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates, stereoisomers, tautomers, racemates, regioisomers, prodrugs, metabolites, polymorphs or jV-oxides, wherein Z is -(CH2)n-X- or -X-(CH2)n-, X is -NRi, -O- or -S-, n is an integer in the range of 0-2, RI is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl and RI' is alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl), the method comprising (i) hydrolysis of compounds of Formula XVII to give compounds of Formula XXIV, (iii) cyclization of the compounds of Formula XXVI to give compounds of Formula XXVII, (iv) reacting the compounds of Formula XXVII with compounds of Formula XIV wherein Xi is halogen) 14.to give compounds of Formula XXVIII. A method lor the preparation of compounds of Formula XXXIV,Formula XXXIV and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates, stereoisomers, tautomers, racemates, regioisomers, prodrugs, metabolites, polymorphs or TV-oxides, wherein Z is -(CH2),,-X- or -X-(CH2)n-, X is -NRi, -O- or -S-, n is an integer in the range of 0-2, RI is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl)alkyl, (heterocyclyl)alkyl, RI' is alkyl, alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl, aryl, aralkyl, heteroaryl, heterocyclyl, (heteroaryl )alkyl, (heterocyclyl)alkyl) and R^ is hydrogen or alkyl, the method comprising (i) hydrolysis of compounds of Formula XVII to give compounds of Formula XXIV, (iii) reacting the compounds of Formula XXX with compounds of Formula XXXI to give compounds of Formula XXXII, (iv) cyclization of the compounds of Formula XXXII to give compounds of Formula XXXIII,