FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
PROVISIONAL SPECIFICATION / COMPLETE SPECIFICATION (See section 10 and rule 13)
1. TITLE OF THE INVENTION
NOVEL DIPEPTIDYL PEPTIDASE IV (DP-IV) COMPOUNDS
2. APPLICANT(S)
(a) NAME : CADILA PHARMACEUTICALS LTD
(b) NATIONALITY: An INDIAN Company
(c) ADDRESS : "Cadila Corporate Campus", Sarkhej - Dholka Road, Bhat, Ahmedabad
-382210, Gujarat, India
3. PREAMBLE TO THE DESCRITION

PROVISIONAL SPECIFICATION
The following specification describes the invention.

COMPLETE SPECIFICATION
The following opooificotion portioulorly dcochboG tho invention and tho manner in which it is to bo performed


4. DESCRIPTION
{Description starts from next page)

FIELD OF INVENTION
The invention relates to novel anti-diabetic compounds of formula I and includes their stereo isomers and composition containing compound of formula I as pharmaceutical^ active ingredient and process for preparation thereof.

wherein,
A is peptide
B is peptide bond between peptide and substituted amine.
R1, and R2 are as defined in specification,
BACKGROUND OF INVENTION
Various amino peptidases are present in the manmmals and catalyze the sequential release of peptidase from peptides such as, pyroglutamyl aminopeptidase and prolylaminpeptidase in addition to dipeptidy! peptidase. Dipeptidyl peptidase family includes DP II, DP-IV, DP VIII, DP IX. (Curr. Opin. Chem. Biol. 2003, 7, 496) The newly synthesized compounds provide DP-IV inhibition activity sufficiently fast and target rate. The enzyme DP-IV is a part of the CD26 surface region associated with immune regulation, signal transduction and apoptosis. DP-IV enzyme works as a suppressor in the development of cancer and tumours. DP-IV also plays major role in glucose metabolism and responsible for the degradation of incretins such as Glucagon-fike peptide-1 (GLP-1). GLP-1 is an incretin hormon secreted by intestinal L-cells in response to food intake. The active form of GLP-1 is having 30-aminoacid peptide, which stimulates insulin, release, inhibits glucagons release, and slows gastric emptying, each a benefit in control of glucose homeostasis in patients with type II diabetes. The activation of GLP-1 is rapidly inactivated by the plasma DP-IV which cleaves a dipeptide from a N-terminal. (Eur. J. Biochem., 1993, 214, 829 and Endocrinology 1995, 136, 3585). DP-IV inhibitors offers several potential advantages over existing therapies including decreased risk of hypoglycemia, potential weight loss, and the potential for regeneration and differentiation of pancreatic /3- cells. DP-IV also binds to the enzyme adenosine deaminase specifically and with high affinity.
Casomorphin is a particular type of peptide which is protein fragment. Casomorphin can be derived from the digestion of casein proteins in milk and milk products. The most important casomorphins from bovine milk are those released from the digestion of /3-casomorphins, sometimes denoted as BCM followed by numeral indicating the number of amino acids in the sequence. The potential release of /3-casomorphins varies between species and breeds. Casomorphin is a series of peptides ranging from 3 to 8 amino acids. In present invention, we explore the synthesis of peptide derivatives based on amino acid sequencing of Casomorphin peptides. The different peptides derivatives ranging from 2 to 20 amino acids are synthesized using substituted amine derivatives.
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Several DP-IV inhibitors possessing modified praline structure as P2 moiety have been reported as illustrated below. (Bioorg. Med. Chem. Lett. 2008, 16, 190)
• In 2005, Sakashita et al., disclosed that (4-substituted)-L-prolyl-(2S)-2-cyanopyrrolidine showed increased inhibition of DP-IV activity relative to unsaturated analogs and that (4(3-substituted)-L-proly/-(2S)-2-cyanopyrrol(dine showed 20-fold stronger activity than the corresponding 4a isomer. (Bioorg. Med. Chem. Lett. 20Q5, 15, 2441)
• Tsai et al. disclosed that (4βcarbamoyl)-L-prolyl-(2S)-2,Cyanopyrrolidine showed enhanced DP-IV inhibition activity, while (5,5-gem-dimethyl)-L-pro|y|-(2S)-2-cyanopyrrlidine showed as 500 fold decrease of DP-IV inhibition relative to the unsubstituted analog, (Bioorg. Med. Chem. Lett. 2006,16,3268)
• Heins, J. et al discloses that DP-IV is a serine protease that catalyzes the cleavage of dipeptides from the N-terminus of proteins with the sequence H—X—Pro—Y or H—X— Ala—Y (where X,Y = any amino acid, Y # Pro.) (Biochi^ Biophys. Acta., 1988, 954,161)
SUMMARY OF INVENTION
The objective of the invention is to provide novel compounds of formula I and pharmaceutically acceptable salts, enantiomers thereof having inhibiting properties of dipeptidyi peptidase IV enzyme (DP-IV inhibitors) sufficiently fast and target rate.
The invention is also provides to pharmaceutical compositions comprising these compounds and the use of these compounds along with its; composition in the prevention or treatment of diseases associated with DP-IV enzyme.
wherein,
A is peptide
B is peptide bond between peptide and substjtuted amine.
R1, and R2 are as defined in specification
DESCRIPTION OF INVENTION
The newly synthesized peptide derivatives can be used in the treatment of various disorders, especially metabolic disorder associated with diabetes mellitus.
We disclose herein a series of novel compounds that are potential proteases inhibitors. The invention relates to novel peptide derivatives of the formula, |,

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wherein,
A is peptide;
A is further defined as R3-R4 wherein R3 and R4 are together or independently defined as peptides having amino acids ranging from 1 to 10. The amino acids for the formation of peptides are selected from naturally occurring or synthetic amino acid analogues. The preferred peptides are formed using amino acids selected from glycine, alanine, valine, leucine, isoleucine, phenylalanine, methionine, tryptophan, lysine, glutamine, glutamic acid, serine, proline, cysteine, tyrosine, histidine, arginine, asparagines, aspartic acid, threonine or mixtures of amino acid thereof
B is peptide bond between peptide and substituted amine.
R1 and / or R2 is independently selected from unsubstituted or substituted alkyl; unsubstituted or substituted cycloalkyl; unsubstituted or substituted cycloalkylalkoxy; unsubstituted or substituted C1.6 alkylalkoxy; unsubstituted or substituted cycloalkoxy-alkyl; C1-6 alkoxy-C1_6 alkyl; unsubstituted or substituted phenyl; unsubstituted or substituted benzyl; halogenated C1-6 alkyl; C1-6alkoxy-C1-6alkyl; cycloalkoxy-C1-6alkyl; unsubstituted or substituted aryl; unsubstituted or substituted bicyclo C4-C15 compound; heterocycle which may be saturated or unsaturated comprising 1-4 heteroatoms independently selected from N, S and O; the heterocycle being unsubstituted or substituted with 1-3 substituents independently selected from oxo; OH; halogen; C1-6 alkyl; and OC1-6 alkyi, wherein the C1-6 alkyl and OC1-6 alkyl are linear or branched and optionally substituted with 1-5 halogens or
R, and R2 together or independently defined as hydrogen or,

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The term "alkyloxycarbonyl" refers to straight or branched chain esters of a carboxylic acid derivative of the present invention of the number of carbon atoms specified (e.g., C1-6 alkyloxycarbonyl), or any number within this range [i.e., methyloxycarbonyl (MeOCO-), ethyloxycarbonyl, or butyloxycarbonyl].
"Halogen" or "Halo" refers to fluorine, chlorine, bromine and iodine. Chlorine and fluorine are generally preferred. Fluorine is most preferred when the halogens are substituted on an alkyl or alkoxy group (e.g. CF30 and CF3CH20).
"Aryl" means a mono- or polycyclic aromatic ring system containing carbon ring atoms. The preferred aryls are monocyclic or bicyclic 6-10 membered aromatic ring systems.
"Heterocycle" and "heterocyclyl" refer to saturated or unsaturated non-aromatic rings or ring systems containing at least one heteroatom selected from O, S and N, further including the oxidized forms of sulfur, namely SO and S02. Examples of heterocycles include tetrahydrofuran (THF), dihydrofuran, 1,4-dioxane, morpholine, 1,4-dithiane, piperazine, piperidine, 1,3-dioxolane, imidazolidine, imidazoline, pyrroline, pyrrolidine, tetrahydropyran, dihydropyran, oxathiolane, dithiofane, 1,3-dioxane, 1,3-dithiane, oxathiane, thiomorpholine, and the like.
"Heteroaryl" means an aromatic or partially aromatic heterocycle that contains at least one ring heteroatom selected from 0, S and N. Heteroaryls also include heteroaryls fused to other kinds of rings, such as aryls, cycioalkyls and heterocycles that are not aromatic. Examples of heteroaryl groups include pyrrolyl, isoxazolyl, isothiazolyl, pyrazolyl, pyridinyl, 2-oxo-(1H)-pyridinyl (2-hydroxy-pyridinyl), oxazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, thiadiazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, furyl, triazinyl, thienyl, pyrimidinyl, pyrazinyl, benzisoxazolyl, benzoxazolyl, benzothiazolyl, benzothiadiazolyl, dihydrobenzofuranyl, indolinyl, pyridazinyl, indazolyl, isoindolyl, dihydrobenzothienyl, indolizinyl, cinnolinyl, phthalazinyl, quinazolinyl, naphthyridinyl, carbazolyl, benzodioxolyl, quinoxalinyl, purinyl, furazanyl, isobenzylfuranyl, benzimidazolyl, benzofuranyl, benzothienyl, quinolyl, indolyl, isoquinolyl, dibenzofuranyl, imidazo[1,2-aJpyridinyl, [1,2,4-triazolojr4,3-a]pyridinyl, pyrazolo[1,5-a]pyridinyl, [1,2,4-triazoloJ[1,5-ajpyridinyl, 2-oxo-1,3-benzoxazolyl, 4-oxo-3H-quinazolinyl, 3-oxo-{1,2,4]-triazolo[4,3-a]-2H-pyridinyl, 5-oxo-[1,2,4]-4H-oxadiazolyl, 2-oxo-[1,3,4]-3H-oxadiazolyl, 2-oxo-1,3-dihydro-2H-imidazolyl, 3-oxo-2,4-dihydro-3H-1,2,4-triazolyl, and the like. For heterocyclyl and heteroaryl groups, rings and ring systems containing from 3-15 atoms are included, forming 1-3 rings.
All Aryl and heteroaryl in aryl-C1-6alkoxy, aryl-C1-6alkyl and the like is for example, phenyl, naphthyl that is unsubstituted or mono, di- or tri- substituted by linear or branched or its unsubstituted or substituted 1-5 halogenated-alkyl, halogen, trifluoromethyl, trifluoromethyloxy, pentafiuorometyl, pentafluoromethyloxy and/or trifluoroethyl,
Bicyclo compound is for example C4 to C25 member, preferably 5-, 6-, 7,- 8-, 9-, 10-member bicycle compounds which is unsubstituted or substituted with heterocycle or may include any of the possible functions groups. The possible substitution in compound of formula I or its analogues contain any of the hydrogen, OH, carboxy, halogen, amino, amido, cyano, ester, acid chloride, carboxylic acid, aldehyde, ether, anhydride, acetyl, acetoxy, substituted phenyl, substituted benzyl.
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The term "pharmaceutically acceptable salts" refers to salts prepared from pharmaceutically acceptable non-toxic bases or acids including inorganic or organic bases and inorganic or organic acids. Salts derived from inorganic bases include aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic salts, manganous, potassium, sodium, zinc, and the like. Particularly preferred are the ammonium, calcium, magnesium, potassium, and sodium salts. Salts in the solid form may exist in more than one crystal structure, and may also be in the form of hydrates. Salts derived from pharmaceuticaily acceptable organic non-toxic bases include salts of primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines, and basic ion exchange resins, N.N'-dibenzylethylene-diamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamime, N-ethyl-morphoJine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethyiamine, trimethylamine, tripropylamine, tromethamine, and the like.
When the compound of the present invention is basic, salts may be prepared from pharmaceutically acceptable non-toxic acids, including inorganic and organic acids. Such acids include acetic, benzenesulfonic, benzoic, camphorsulfonic, citric, ethanesulfonic, fumaric, gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic, pantothenic, phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic acid, and the like. Particularly preferred are citric, hydrobromic, hydrochloric, maleic, phosphoric, sulfuric, fumaric, tartaric acids and the like.
It will be understood that, as used herein, references to the compounds of formula I are meant to also include the pharmaceutically acceptable salts.
As appreciated by those of skill in the art, halo or halogen as used herein are intended to include fluoro, chloro, bromo and iodo. Similarly, C1-8 as in C1-6 alkyl is defined to identify the group as having 1, 2, 3, 4, 5, 6, 7 or 8 carbons in a linear or branched arrangement, such thatC1-8 alkyl specifically includes methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, pentyl, hexyl, heptyl and octyl. Likewise, C0l as in C0 alkyl is defined to identify the presence of a direct covalent bond. A group which is designated as being independently substituted with substituents may be independently substituted with multiple numbers of such substituents.
The compounds of the present invention may contain one or more asymmetric centres and can thus occur as racemates and racemic mixture, single enantiomers, diastereomeric mixtures and individual diastereomers. The compounds of the instant invention have one asymmetric centre at beta carbon atom. Additional asymmetric centres may be present depending upon the nature of the various substituents on the molecule. Each such asymmetric center will independently produce two optical isomers and it is intended that all of the possible optical isomers and diastereomers in mixtures and as pure or partially purified compound are included within the ambit of this invention. The present invention is meant to comprehend all such isomeric forms of these compounds.
The compound described herein can contain olefinic double bonds, and unless specific otherwise, are meant to include both E and Z geometric isomers.
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The compound described herein can exist as tutomers. The individual tautomers as well as mixtures thereof are encompassed with compounds of the present invention.
Formula I shows the structure of the class of compounds without preferred stereochemistry. The preferred sterochemistry at the carbon atom which is attached to and R9 of the beta amino acid from which these compounds are prepared.
The independent syntheses of these peptide derivatives or their chromatographic separations may be achieved as known in the art by appropriate modification of the methodology disclosed herein. Their absolute stereochemistry can be determined by the x-ray crystallography of crystalline products or crystalline intermediates which are derivatized, if necessary, with a reagent containing an asymmetric center of known absolute configuration.
If desired, racemic mixtures of the compounds may preferably separate so that the individual enantiomers are isolated. The separation can be carried out by methods well known in the art, such as the coupling of a racemic mixture of compounds to an enantiomerically pure compound to form a diastereomeric mixture, followed by separation of the individual diastereomers by standard methods, such as fractional crystallization or chromatography. The coupling reaction is often the formation of salts using an enantiomerically pure acid or base. The diasteromeric derivatives may then be converted to the pure enantiomers by cleavage of the added chiral residue. The racemic mixture of the compounds can also be separated directly by chromatographic methods utilizing chiral stationary phases, which methods are well known in the art.
Alternatively, any enantiomer of a compound may be obtained by stereoselective synthesis using optically pure starting materials or reagents of known configuration by methods well known in the art.
The term "composition" as used herein is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts. Such term in relation to pharmaceutical composition, is intended to encompass a product comprising the active ingredients), and the inert ingredient(s) that make up the carrier, as well as any product which resuits, directJy or indirectiy, from combination, compiexaiion or aggregation of any two or more of the ingredients, or from dissociation of one or more of the ingredients, or from other types of reactions or interactions of one or more of the ingredients. Accordingly, the pharmaceutical compositions of the present invention encompass any composition made by admixing a compound of the present invention and a pharmaceutically acceptable carrier. By "pharmaceutically acceptable" it is meant the carrier, diluent or excipient must be compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.
The terms "administration of and/or "administering a" compound should be understood to mean providing a compound of the invention or a prodrug of a compound of the invention to the individual in need of treatment.
The general synthetic route for the preparation of compound having formula 1 involves following general scheme wherein the scheme is exemplified with the selected amino acids as
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proline with different amino acid to form peptides. The peptide compounds synthesized herein using different amino acid consist peptide bond. The intermediate peptide compound further reacts with different primary and secondary amine derivative to give compound of the formula I.

The process disclosed herein is not limited to the preparation of specific compounds as prepared herein but is described the general state of art in order to prepare the compounds of present invention. It also includes a compound which selected from the group consisting of the compounds disclosed in the following examples and pharmaceutically acceptable salts thereof and individual diastereomers thereof.
The compounds disclosed in present invention are prepared by involving preferred process as described in known literature and useful to obtain the medicinally important active ingredient. The synthesized compounds are useful in a method of inhibiting dipeptidyl peptidase-IV enzyme in a patient such as a mammal in need of such inhibition comprising the administration of an effective amount of the compound. Tne present invention is directed" to the use of the compouncfs di'sclc-sed herein as inhibitors of dipeptidyl peptidase-IV enzyme activity.
In addition to primates, such as humans, a variety of other mammals can be treated according to the method of the present invention. For instance, mammals including, but not limited to, cows, sheep, goats, horses, dogs, cats, guinea pigs, rats or other bovine, ovine, equine, canine, feline, rodent or murine species can be treated. However, the method can also be practiced in other species, such as avian species (e.g., chickens).
The present invention is further directed to a method for the manufacture of a medicament for inhibiting DP-IV enzyme activity in humans and animals comprising combining a compound of the present invention with a pharmaceutical carrier or diluent.

While the invention has been described and illustrated with reference to certain particular embodiments thereof, those skilled in the art will appreciate that various adaptations, changes, modifications, substitutions, deletions, or additions of procedures for the preparation of the compounds as described in formula I and may modified departing from the spirit and scope of the invention.
Date: 10 September 2008
For Cadila Pharmaceuticals Ltd.Dr. Bakulesh Khamar
Executive Director - Research

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