Abstract:
Novel antidiabetic compounds, their tautomeric forms, their derivatives, their steroisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates and pharmaceutical acceptable compositions containing them: Methods for preparing the antidiabetic compounds and their uses.

Description:
FIELD OF THE INVENTION 
     The present invention relates to novel antidiabetic compounds, their tautomeric forms, their derivatives, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates and pharmaceutically acceptable compositions containing them. This invention particularly relates to novel azolidinedione derivatives of the general formula (I), their tautomeric forms, their derivatives, their stereoisomers, their polymorphs and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates and pharmaceutical compositions containing them. ##STR1## 
     The present invention also relates to a process for the preparation of the above said novel azolidinedione derivatives, their tautomeric forms, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, pharmaceutically acceptable solvates, novel intermediates and pharmaceutical compositions containing them. 
     The azolidinedione derivatives of the general formula (I) defined above of the present invention are useful for the treatment and/or prophylaxis of diseases or conditions in which insulin resistance is the underlying pathophysiological mechanism. Examples of these diseases and conditions are type II diabetes, impaired glucose tolerance, dyslipidaemia, hypertension, coronary heart disease and other cardiovascular disorders including atherosclerosis. The azolidinedione derivatives of the formula (I) are useful for the treatment of insulin resistance associated with obesity and psoriasis. The azolidinedione derivatives of the formula (I) can also be used to treat diabetic complications and can be used for treatment and/or prophylaxis of other diseases and conditions such as polycystic ovarian syndrome (PCOS), certain renal diseases including diabetic nephropathy, glomerulonephritis, glomerular sclerosis, nephrotic syndrome, hypertensive nephrosclerosis, end-stage renal diseases and microalbuminuria as well as certain eating disorders, as aldose reductase inhibitors and for improving cognitive functions in dementia. 
     BACKGROUND OF THE INVENTION 
     Insulin resistance is the diminished ability of insulin to exert its biological action across a broad range of concentrations. In insulin resistance, the body secretes abnormally high amounts of insulin to compensate for this defect; failing which, the plasma glucose concentration inevitably rises and develops into diabetes. Among the developed countries, diabetes mellitus is a common problem and is associated with a variety of abnormalities including obesity, hypertension, hyperlipidemia (J. Clin. Invest., (1985) 75: 809-817; N. Engl. J. Med. (1987) 317: 350-357; J. Clin. Endocrinol. Metab., (1988) 66: 580-583; J. Clin. Invest., (1975) 68: 957-969) and other renal complications (See Patent Application No. WO 95/21608). It is now increasingly being recognized that insulin resistance and relative hyperinsulinemia have a contributory role in obesity, hypertension, atherosclerosis and type 2 diabetes mellitus. The association of insulin resistance with obesity, hypertension and angina has been described as a syndrome having insulin resistance as the central pathogenic link-Syndrome-X. In addition, polycystic ovarian syndrome (Patent Application No. WO 95/07697), psoriasis (Patent Application No. WO 95/35108), dementia (Behavioral Brain Research (1996) 75: 1-11) etc. may also have insulin resistance as a central pathogenic feature. 
     A number of molecular defects have been associated with insulin resistance. These include reduced expression of insulin receptors on the plasma membrane of insulin responsive cells and alterations in the signal transduction pathways that become activated after insulin binds to its receptor including glucose transport and glycogen synthesis. Since defective insulin action is thought to be more important than failure of insulin secretion in the development of non-insulin dependent diabetes mellitus and other related complications, this raises doubts about the intrinsic suitability of antidiabetic treatment that is based entirely upon stimulation of insulin release. 
     Recently, Takeda has developed a new class of compounds which are the derivatives of 5-(4-alkoxybenzyl)-2,4-thiazolidinediones of the formula (II) (Ref Chem. Pharm Bull. 1982, 30, 3580-3600). In the formula (II), V represents substituted or unsubstituted divalent aromatic group and U represents various groups which have been reported in various patent documents. ##STR2## 
     By way of examples, U may represent the following groups: 
     (i) a group of the formula (IIa) where R 1  is hydrogen or hydrocarbon residue or heterocyclic residue which may each be substituted, R 2  is hydrogen or a lower alkyl which may be substituted by hydroxy group, X is an oxygen or sulphur atom, Z is a hydroxylated methylene or a carbonyl, m is 0 or 1, n is an integer of 1-3. These compounds have been disclosed in the European Patent Application No. 0 177 353. ##STR3## 
     An example of these compounds is shown in formula (IIb) ##STR4## (ii) a group of the formula (IIc) wherein R 1  and R 2  are the same or different and each represents hydrogen or C 1  -C 5  alkyl, R 3  represents hydrogen, acyl group, a (C 1  -C 6 ) alkoxycarbonyl group or aralkyloxycarbonyl group, R 4  -R 5  are same or different and each represent hydrogen, C 1  -C 5  alkyl or C 1  -C 5  alkoxy or R 4 , R 5  together represent C 1  -C 4  alkenedioxy group, n is 1, 2, or 3, W represents CH 2 , CO, CHOR 6  group in which R 6  represents any one of the items or groups defined for R 3  and may be the same or different from R 3 . These compounds are disclosed in the European Patent Application No. 0139421. ##STR5## 
     An example of these compounds is shown in (IId) ##STR6## iii) A group of formula (IIe) where A 1  represents substituted or unsubstituted aromatic heterocyclic group, R 1  represents a hydrogen atom, alkyl group, acyl group, an aralkyl group wherein the aryl moiety may be substituted or unsubstituted, or a substituted or unsubstituted aryl group, n represents an integer in the range from 2 to 6. These compounds are disclosed in European Patent No. 0306228. ##STR7## 
     An example of this compound is shown in formula (IIf) ##STR8## iv) A group of formula (IIg) where Y represents N or CR 5 , R 1 , R 2 , R 3 , R 4  and R 5  represents hydrogen, halogen, alkyl and the like and R 6  represents hydrogen, alkyl, aryl and the like, n represents an integer of 0 to 3. These compounds are disclosed in European Patent Application No. 0604983. ##STR9## 
     An example of this compound is shown in formula (IIh) ##STR10## v) A group of formula (IIi a-d) where R 1  represents hydrogen atom, halogen, linear or branched (C 1  -C 6 )alkyl, (C 1  -C 6 )alkoxy, trifluoromethyl or cyano groups and X represents S, O or NR where R═H or (C 1  -C 6 )alkyl group. These compounds are disclosed in European patent application No. 0528734. ##STR11## 
     An example of this class of compound is shown in formula (IIj) ##STR12## 
     Still another class of antihyperglycemic agents are 5-substituted oxazolidine-2,4-diones and 2-substituted-1,2,4-oxadiazolidine-3,5-diones which can be represented in the formula (IIk), ##STR13## where V represents substituted or unsubstituted divalent aryl or hetero aryl group, W represents various groups which have been reported in various patent documents, A represents nitrogen atom or a CH group and B is an oxygen atom. 
     By way of examples, W may represent the following groups: 
     vi) a group of formula (II 1), where R is (C 1  -C 6 ) alkyl groups, cycloalkyl group, furyl, thienyl, substituted or unsubstituted phenyl group, X is hydrogen, methyl, methoxy, chloro or fluoro. 
     These compounds have been disclosed in the U.S. Pat. No. 5,037,842. ##STR14## 
     An example of these compounds is shown in formula (IIm). ##STR15## (vii) A group of formula (IIn) wherein A 1  represents a substituted or unsubstituted aromatic heterocyclyl group; R 1  represents a hydrogen atom, an alkyl group, an acyl group, an aralkyl group, wherein the aryl moiety may be substituted or unsubstituted or a substituted or unsubstituted aryl group, n represents an integer in the range of from 2 to 6. These compounds have been disclosed in the Patent Application No. WO 92/02520. ##STR16## 
     An example of these compounds is shown in formula (IIo) ##STR17## (viii) A group of formulae (IIp) and (IIq), where R 1  is hydrogen, (C 1  -C 8 )alkyl, (C 1  -C 8 )alkoxy, trifluoroalkoxy, halogen or trifluoromethyl group, R 2  is hydrogen or methyl and X is oxygen or sulfur. These compounds have been described in U.S. Pat. No. 5,480,486. ##STR18## 
     An example of these compounds is shown in formula (IIr) ##STR19## 
     SUMMARY OF THE INVENTION 
     With an objective of developing new compounds for the treatment of type II diabetes  non-insulin-dependent-diabetes mellitus (NIDDM)! which could be more potent at relatively lower doses and having better efficacy with lower toxicity, we focused our research efforts in a direction of incorporating safety and to have better efficacy, which has resulted in the development of novel azolidinedione derivatives having the general formula (I) as defined above. 
     The main objective of the present invention is therefore, to provide novel azolidinedione derivatives, their tautomeric forms, their stereoisomers, their polymorphs, their pharmaceutically, acceptable salts, their pharmaceutically acceptable solvates and pharmaceutical compositions containing them, or their mixtures. 
     Another objective of the present invention is to provide novel azolidinedione derivatives, their tautomeric forms, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates and pharmaceutical compositions containing them or their mixtures having enhanced activities, no toxic effect or reduced toxic effect. 
     Yet another objective of the present invention is to produce a process for the preparation of novel azolidinediones of the formula (I) as defined above, their tautomeric forms, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts and their pharmaceutically acceptable solvates. 
     Still another objective of the present invention is to provide pharmaceutical compositions containing compounds of the general formula (I), their tautomers, their stereoisomers, their polymorphs, their salts, solvates or their mixtures in combination with suitable carriers, solvents, diluents and other media normally employed in preparing such compositions. 
     Yet another objective of the present invention is to provide a process for the preparation of the novel intermediate of the formula (III) ##STR20## where G represents --CHO, --NO 2 , --NH 2 ,--CH═NHOH, --CH 2  NHOH, --CH 2  N(OH)CONH 2  or --CH 2  CH(J)--COOR, where J represents hydroxy group, halogen atom such as chlorine, bromine or iodine and R represents H or lower alkyl group such as methyl, ethyl or propyl. A, W, Q, B, D, X, k, p and Ar are as defined in formula (I). 
     DETAILED DESCRIPTION OF THE INVENTION 
     Azolidinedione derivatives of the present invention have the general formula (I) ##STR21## 
     In the above formula (I), A represents substituted or unsubstituted, single or fused, aromatic group or substituted or unsubstituted, single or fused, heterocyclic group with one or more hetero atoms selected from the group of nitrogen, oxygen and sulfur, W represents a heteroatom selected from the group oxygen, sulfur or a group NR 2 , where R 2  may be hydrogen atom or a lower alkyl group, Q represents a heteroatom selected from oxygen, sulfur or a group NR 3  where R 3  may be hydrogen atom, lower alkyl or lower alkoxy group, B and D each represent substituted or unsubstituted hydrocarbon linking group between N and X which may be saturated or may contain one or more double bonds, X represents, either a CH 2  group or a hetero atom selected from the group of nitrogen, sulfur or oxygen, Ar represents an optionally substituted divalent single or fused aromatic or optionally substituted single or fused heterocyclic group, R 1  represents hydrogen atom, hydroxy, alkoxy, halogen or lower alkyl group or forms a bond together with the adjacent group Y. Y represents a nitrogen atom or a group CR 6  where R 6  represents hydrogen, hydroxy, alkoxy, halogen or lower alkyl group such as methyl, ethyl, propyl, and the like or R 6  forms a bond together with R 1  ; Z represents a oxygen atom or a sulfur atom when Y is CR 6  and Z represents an oxygen atom when Y is a nitrogen atom, k is a integer raging from 1-4 and p an integer raging from 0-4. 
     Suitable aromatic groups represented by A include phenyl, naphthyl, phenanthryl, indenyl, fluorenyl, preferably, phenyl and naphthyl groups. Suitable heterocyclic groups, represented by A include furyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, pyrazolyl, imidazolyl, pyridyl, pyridonyl, pyrimidyl, pyrimidonyl, pyridazyl, pyrazinyl, dihydrobenzofuranyl, benzofuranyl, benzothienyl, benzopyranyl, indolyl, benzoxazolyl, benzothiazolyl, benzopyrazolyl, purinyl, phthalazinyl, phthalazinonyl, quinoxalinyl, quinoxalonyl, quinazolinyl, quinazolinonyl, pyridopyrimidinyl, azaindolyl, pyridinoimidazolyl, naphthyridinyl, benzimidazolyl, quinolyl, quinalonyl, carbazolyl, phenazinyl, phenoxazinyl, phenothiazinyl, benzoxazinyl, benzoxazinonyl and the like. 
     Preferred groups represented by A include phenyl, naphthyl, benzothiazolyl, oxazolyl, pyridyl, indolyl, fluorenyl, pyrimidonyl, quinazolinonyl, benzoxazinonyl groups. 
     More preferred groups represented by A include phenyl and pyridyl group. 
     One or more of the suitable substituents on the aromatic and heterocyclic group represented by A include hydroxy, amino group, halogen atoms such as chlorine, fluorine, bromine, iodine, substituted or unsubstituted (C 1  -C 12 )alkyl group, especially, linear or branched (C 1  -C 6 )alkyl group, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, t-butyl, pentyl, hexyl and the like; cycloalkyl group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like; cycloalkyloxy group such as cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, cyclohexyloxy and the like; aryl group such as phenyl or naphthyl, the aryl group may be substituted; aralkyl such as benzyl or phenethyl, the aralkyl group may be substituted; heteroaryl group such as pyridyl, thienyl, furyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, oxadiazolyl, tetrazolyl, benzopyranyl, benzofuranyl and the like, the heteroaryl group may be substituted; heterocyclyl groups such as aziridinyl, pyrrolidinyl, morpholinyl, piperidinyl, piperazinyl and the like, the heterocyclyl group may be substituted; aryloxy such as phenoxy, naphthyloxy, the aryloxy group may be substituted; alkoxycarbonyl such as methoxycarbonyl or ethoxycarbonyl; aryloxycarbonyl group such as optionally substituted phenoxycarbonyl; arylmino group such as HNC 6  H 5  ; amino(C 1  -C 6 )alkyl; hydroxy(C 1  -C 6 )alkyl; (C 1  -C 6 )alkoxy; thio(C 1  -C 6 )alkyl; (C 1  -C 6 ) alkylthio; acyl group such as acetyl, propionyl or benzoyl, the acyl group may be substituted; acylamino groups such as NHCOCH 3 , NHCOC 2  H 5 , NHCOC 3  H 7 , NHCOC 6  H 5 , aralkoxycarbonyl amino group such as NHCOOCH 2  C 6  H 5 , alkoxycarbonylamino group such as NHCOOC 2  H 5 , NHCOOCH 3  and the like, carboxylic acid or its derivatives such as amides, like CONH 2 , CONHMe, CONMe 2 , CONHEt, CONEt 2 , CONHPh and the like, the carboxylic acid derivatives may be substituted, acyloxy group such as OOCMe, OOCEt, OOCPh and the like which may optionally be substituted; sulfonic acid or its derivatives such as SO 2  NH 2 , SO 2  NHMe, SO 2  NMe 2 , SO 2  NHCF 3 , SO 2  NHPh and the like; the sulfonic acid derivatives may be substituted. 
     All of the suitable substituents on group A may be substituted or unsubstituted. 
     When the substituents are further substituted, the substituents selected are from the same groups as those groups that substitute A and may be selected from halogen, hydroxy, or nitro, or optionally substituted groups selected from alkyl, cycloalkyl, alkoxy, cycloalkoxy, aryl, aralkyl, heterocyclyl, heteroaryl, heteroaralkyl, acyl, acyloxy, hydroxyalkyl, amino, acylamino, arylamino, aminoalkyl, aryloxy, alkoxycarbonyl, alkylamino, alkoxyalkyl, alkylthio, thioalkyl groups, carboxylic acid or its derivatives, or sulfonic acid or its derivatives. 
     Suitable group represented by W includes oxygen, sulfur, or a group NR 2 , where R 2  is selected from hydrogen or lower alkyl groups such as methyl, ethyl, or propyl groups. 
     It is preferred that W represents a oxygen or a group NR 2  where R 2  is preferably hydrogen atom. 
     Suitable Q includes oxygen, sulfur or a group NR 3 , where R 3  is selected from hydrogen, (C 1  -C 4 )alkoxy groups or lower alkyl groups such as methyl, ethyl, or propyl groups. 
     It is preferred that Q represents oxygen atom. 
     Suitable hydrocarbon linking group between N and X represented by B may contain 1-4 carbon atoms, 1-2 being preferred and suitable linking group between N and X represented by D may represent either a bond or contain 1-4 carbon atoms, 1-2 being preferred. The compounds according to formula (I) always have a linking group B and a linking group D. The linking group D having no carbon atom means that the linking group D represents a bond. B and D may contain no double bond or contain one to two double bonds, no double bond or one double bond being preferred. The substituents on B and D include hydroxy, amino groups, halogen such as chlorine, bromine, and iodine, optionally substituted linear or branched (C 1  -C 12 )alkyl, especially (C 1  -C 6 )alkyl group such as methyl, hydroxymethyl, aminomethyl, methoxymethyl, trifluoromethyl, ethyl, isopropyl, hexyl etc; (C 3  -C 6 )cycloalkyl groups such as cyclopropyl, fluorocyclopropyl, cyclobutyl, cyclopentyl, fluorocyclopentyl, cyclohexyl, fluorocyclohexyl and the like; (C 1  -C 6 )alkoxy, (C 3  -C 6 )cycloalkoxy, aryl such as phenyl; heterocyclic groups such as furyl, thienyl and the like; (C 2  -C 6 ) acyl, (C 2  -C 6 )acyloxy, hydroxy (C 1  -C 6 )alkyl, amino(C 1  -C 6 )alkyl, mono or di (C 1  -C 6 )alkylamino, cyclo(C 3-C   5 )alkylamino groups; two substituents together with the adjacent carbon atoms to which they are attached may form a substituted or unsubstituted 5-7 membered cyclic structure which may or may not contain one or more hetero atoms selected from N, O, and S; such cyclic structures may or may not contain one or more double bonds. Preferred ring structures include phenyl, naphthyl, pyridyl, thienyl, furyl, oxazolyl, thiazolyl, furyl, isoxazolyl, azepinyl and the like. The substituents on such cyclic structure may be selected from the same group that may substitute the aromatic and heterocyclic group represented by A. 
     Suitable X includes CH 2 , oxygen, nitrogen or sulfur group, preferably CH 2  or O. Preferred ring structures comprising a nitrogen atom, linking groups represented by B and D, and X are pyrrolidinyl, piperidinyl, piperazinyl, aziridinyl, and morpholinyl groups. 
     It is more preferred that the ring structures comprising a nitrogen atom, linking groups represented by B and D, and X is a piperidinyl, pyrrolidinyl or a morpholinyl group. 
     The group represented by Ar includes divalent phenylene, naphthylene, pyridyl, quinolinyl, benzofuranyl, benzoxazolyl, benzothiazolyl, indolyl, indolinyl, azaindolyl, azaindolinyl, indenyl, pyrazolyl and the like. The substituents on the group represented by Ar include linear or branched optionally halogenated (C 1  -C 6 )alkyl and optionally halogenated (C 1  -C 3 )alkoxy, halogen, acyl, amino, acylamino, thio, carboxylic and sulfonic acids and their derivatives. 
     It is more preferred that Ar represents substituted or unsubstituted divalent phenylene, naphthylene, benzofuranyl, indolyl, indolinyl, quinolinyl, azaindolyl, azaindolinyl, benzothiazolyl or benzoxazolyl groups. 
     It is still more preferred that Ar is represented by divalent phenylene or naphthylene, which may be optionally substituted by methyl, halomethyl, methoxy or halomethoxy groups. 
     Suitable R 1  includes hydrogen, lower alkyl groups such as methyl ethyl or propyl; hydroxy, (C 1  -C 3 )alkoxy; halogen atom such as fluorine, chlorine, bromine, or iodine or R 1  together with Y represents a bond. 
     It is preferred that R 1  is hydrogen or forms a bond together with Y. 
     Suitable Y group may be nitrogen or CR 6  where R 6  may be a hydrogen atom, hydroxy, (C 1  -C 3 )alkoxy, halogen, lower alkyl group; (C 1  -C 3 )alkyl being the preferred lower alkyl group; or together with R 1  forms a bond. 
     It is preferred that Y forms a bond together with adjacent group R 1  or Y represents CR 2  where R 2  is hydrogen atom. 
     Suitable Z group includes a hetero atom selected from O or S, with the provision that when Y is CR 6 , Z is selected from sulfur or oxygen, and when Y is nitrogen, Z represents oxygen. 
     Suitable ring structures comprising Y and Z include 2,4-dioxooxazolidin-5-yl, 2,4-dioxothiazolidin-5-yl, and 3,5-dioxo-1,2,4-oxadiazolidin-2-yl groups. Preferred ring structures comprising Y and Z include 2,4-dioxooxazolidin-5-yl and 2,4-dioxothiazolidin-5-yl groups. 
     It is more preferred that the ring structure comprising Y and Z is a 2,4-dioxothiazolidin-5-yl group. 
     Suitable k is an integer ranging 0 to 4, especially 1 to 2 and suitable p is an integer ranging from 0 to 4. It is preferred that p is 1 or 0. When p is zero (CH 2 )p represents a bond; the ring structure comprising N, X and the linking groups B and D is directly linked to the oxygen atom. 
     Pharmaceutically acceptable salts forming part of this invention include salts of the azolidinedione moiety such as alkali metal salts like Li, Na, and K salts, alkaline earth metal salts like Ca and Mg salts, salts of organic bases such as lysine, arginine, guanidine, diethanolamine, choline and the like, ammonium or substituted ammonium salts, salts of carboxy group wherever appropriate, such as aluminum, alkali metal salts, alkaline earth metal salts, ammonium or substituted ammonium salts. Salts may include acid addition salts which are sulphates, nitrates, phosphates, perchlorates, borates, hydrohalides, acetates, tartrates, maleates, citrates, succinates, palmoates, methanesulphonates, benzoates, salicylates, hydroxynaphthoates, benzene sulfonates, ascorbates, glycerophosphates, ketoglutarates and the like. Pharmaceutically acceptable solvates may be hydrates or comprise other solvents of crystallization such as alcohols. 
     Particularly useful compounds according to the invention include: 
     5- 4- 1-(Benzyloxycarbonyl)piperidin-4-yloxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)piperidin-4-yloxy!phenyl methyl!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)piperidin-4-ylmethoxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)piperidin-4-ylmethoxy!phenyl methyl!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)-(2S)-pyrrolidin-2-ylmethoxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)-(2R)-pyrrolidin-2-ylmethoxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4-  1-(Benzyloxycarbonyl)-(2S)-pyrrolidin-2-ylmethoxy!phenyl methyl!thiazolidine-2,4-dione; 
     5- 4-  1-(Benzyloxycarbonyl)-(2R)-pyrrolidin-2-ylmethoxy!phenyl methyl!thiazolidine-2,4-dione; 
     5- 4- 1-(Fluoren-9-ylmethoxycarbonyl)piperidin-4-yloxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4- 1-(Phenoxycarbonyl)piperidin-4-yloxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4- 1-(Anilinocarbonyl)piperidin-4-yloxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzylaminocarbonyl)piperidin-4-yloxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzylaminocarbonyl)piperidin-4-yloxy!phenyl methyl!thiazolidine 2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)-(3S)-morpholin-3-ylmethoxy!phenyl methylene!thiazolidine-2,4 dione; 
     5- 4- 1-(Benzyloxycarbonyl)-(3R)-morpholin-3-ylmethoxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)-(3S)-morpholin-3-ylmethoxy!phenyl methyl!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)-(3R)-morpholin-3-ylmethoxy!phenyl methyl!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)-(2S)-morpholin-2-ylmethoxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)-(2R)-morpholin-2-ylmethoxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl-(2S)-morpholin-2-ylmethoxy!phenyl methyl!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)-(2R)-morpholin-2-ylmethoxy!phenyl methyl!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)-(2S)-aziridin-2-ylmethoxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)-(2R)-aziridin-2-ylmethoxy!phenyl methylene!thiazolidine-2,4-dione; 
     5- 4- 1-(Benzyloxycarbonyl)-(2S)-aziridin-2-ylmethoxy!phenyl methyl!thiazolidine-2,4-dione; and 
     5- 4- 1-(Benzyloxycarbonyl)-(2R)-aziridin-2-ylmethoxy!phenyl methyl!thiazolidine-2,4-dione. 
     According to a feature of the present invention, there is provided a process for the preparation of novel intermediate of the general formula (III) ##STR22## where A, W, Q, B, D, X, Ar, k and p are as defined in formula (I) and G is as defined earlier. 
     In an embodiment of the invention, the novel intermediate of the general formula (III) defined above where G is CHO or NO 2  group, can be prepared by reacting the compound of the general formula (IV) ##STR23## wherein A, W, Q, B, D, X, k and p are as defined earlier and L 1  is a halogen atom such as chlorine, bromine or iodine or a leaving group such as methanesulfonate, trifluoromethanesulfonate, p-toluenesulfonate and the like with a compound of the formula (V) 
     
         HO--Ar--G                                                  (V) 
    
     where G is a CHO or a NO 2  group and Ar is as defined earlier. 
     The reaction of compound of formula (IV) with the compound of formula (V) to produce a compound of formula (III) may be carried out in the presence of solvents such as THF, DMF, DMSO, DME and the like. Mixtures of solvents may be used. The reaction may be carried out in an inert atmosphere. The inert atmosphere may be maintained by using inert gases such as N 2 , Ar or He. The reaction may be effected in the presence of a base such as K 2  CO 3 , Na 2  CO 3 , NaH, or a mixture thereof. The reaction temperature may range from 20° C. to 150° C., preferably at a temperature in the range of 30° C. to 100° C. The duration of the reaction may range from 1 to 24 hours, preferably from 2 to 12 hours. 
     In another embodiment of the present invention, the novel intermediate of general formula (III), where G is a CHO or NO 2  group, can also be prepared by the reaction of compound of general formula (VI) ##STR24## where A, W, Q, B, D, X, k and p are as defined earlier with a compound of general formula (VII) 
     
         L.sup.2 --Ar--G                                            (VII) 
    
     where G is a CHO or NO 2  group and Ar is as defined earlier and L 2  represents a halogen atom such as chlorine or fluorine. 
     The reaction of the compound of formula (VI) with compound of formula (VII) to produce a compound of the formula (III) may be carried out in the presence of solvents such as THF, DMF, DMSO, DME and the like or mixtures thereof. The reaction may be carried out in an inert atmosphere which is maintained by using inert gases such as N 2 , Ar, or He. The reaction may be effected in the presence of a base such as K 2  CO 3 , Na 2  CO 3  or NaH or a mixture thereof. The reaction temperature may range from 20° C. to 120° C., preferably at a temperature in the range of 30° C. to 100° C. The duration of the reaction may range from 1 to 24 hours, preferably from 2 to 12 hours. 
     The novel intermediate of formula (III) can also be obtained by the reaction of a compound of general formula (VI) defined above with a compound of general formula (V) defined earlier. 
     The reaction of compound of general formula (VI) with a compound of general formula (V) may be carried out using suitable coupling agents such as dicyclohexyl urea, triarylphosphine/dialkylazadicarboxylate such as PPh 3  /DEAD and the like. The reaction may be carried out in the presence of solvents such as THF, DME, CH 2  Cl 2 , CHCl 3 , toluene, acetonitrile, carbontetrachloride and the like. The reaction may be carried out in an inert atmosphere. The inert atmosphere may be maintained by using inert gases such as N 2 , Ar, or He. The reaction may be effected in the presence of DMAP, HOBT and they may be used in the range of 0.05 to 2 equivalents, preferably 0.25 to 1 equivalents. The reaction temperature may be in the range of 0° C. to 110° C., preferably at a temperature in the range of 20° C. to 80° C. The duration of the reaction may range from 0.5 to 24 hours, preferably from 2 to 12 hours. 
     In another embodiment of this invention, there is provided a process for the preparation of a compound of general formula (III) where G is a CHO or a NO 2  group, and other symbols are as defined earlier which comprises reacting a compound of general formula (VIII) ##STR25## where B, D, X, Ar and p are as defined earlier, with a compound of general formula (IX) ##STR26## where A, W, Q, L 1  and k are as defined earlier. 
     The reaction of compound of general formula (VIII) with a compound of general formula (IX) may be carried out neat or in the presence of solvents such as DMF, DMSO, CH 3  CN, EtOH, THF, dioxane, acetone and the like. Aqueous media may be used. The reaction may be carried out in an inert atmosphere. The inert atmosphere may be maintained by using inert gases such as N 2 , Ar, or He. The reaction may be effected in the presence of base such as K 2  CO 3 , Na 2  CO 3 , KOH, NaOH, NaH and the like or mixtures thereof. The amount of base may range from 1 to 20 equivalents, preferably 1 to 10 equivalents. The reaction may be carried out at a temperature in the range 0° C. to 180° C., preferably at a temperature in the range 0° C. to 150° C. Duration of the reaction may range from 1 to 48 hours, preferably from 1 to 12 hours. The amounts of the compounds of general formula (VIII) and (IX) may range from 1 to 20 equivalents, preferably from 1 to 5 equivalents. 
     The compound of general formula (VIII) in turn can be prepared by reacting a compound of general formula (X) ##STR27## where B, D, L 1 , X and p are as defined earlier and R 4  is a hydrogen atom or a protecting group, with a compound of general formula (V) followed by removal of N-protecting group using conventional methods. 
     The reaction of compound of general formula (X) with a compound of general formula (V) may be carried out in the presence of solvents such as THF, DMF, DMSO, DME and the like or mixture thereof. The reaction may be carried out in an inert atmosphere. The inert atmosphere may be maintained by using inert gases such as N 2 , Ar, or He. The reaction may be effected in the presence of a base such as K 2  CO 3 , Na 2  CO 3 , NaH and the like or a mixture thereof. The reaction temperature may range from 20° C. to 120° C., preferably at a temperature in the range of 30° C. to 80° C. The duration of the reaction may range from 1 to 24 hours, preferably from 2 to 12 hours. 
     The compound of general formula (VIII) can also be prepared by reacting a compound of general formula (XI) ##STR28## where B, D, X, p, and R 4  are as defined earlier, with a compound of general formula (V) or with a compound of general formula (VII) defined earlier. 
     The reaction of a compound of general formula (XI) with compound of general formula (V) may be carried out using suitable coupling agents such as dicyclohexyl urea, triarylphosphine/dialkylazadicarboxylate such as PPh 3  /DEAD and the like. The reaction may be carried out in the presence of solvents such as THF, DME, CH 2  Cl 2 , CHCl 3 , toluene, acetonitrile, carbontetrachloride and the like. The reaction may be carried out in an inert atmosphere. The inert atmosphere may be maintained by using inert gases such as N 2 , Ar, or He. The reaction may be effected in the presence of DMAP, HOBT and they may be used in the range of 0.05 to 2 equivalents, preferably 0.25 to 1 equivalents. The reaction temperature may be in the range of 0° C. to 100° C., preferably at a temperature in the range of 20° C. to 80° C. The duration of the reaction may range from 0.5 to 24 hours, preferably from 6 to 12 hours. 
     The reaction of compound of general formula (XI) with a compound of general formula (VII) to produce a compound of general formula (VIII) may be carried out in the presence of solvents such as THF, DMF, DMSO, DME and the like or a mixture thereof The reaction may be carried out in an inert atmosphere which is maintained by using inert gases such as N 2 , Ar, or He. The reaction may be effected in the presence of a base such as K 2  CO 3 , Na 2  CO 3  or NaH or a mixture thereof. The reaction temperature may range from 20° C. to 120° C., preferably at a temperature in the range of 30° C. to 100° C. The duration of the reaction may range from 1 to 12 hours, preferably from 2 to 6 hours. 
     The compound of general formula (III) can also be prepared by reacting a compound of general formula (VIII) with a compound of general formula (XII) 
     
         A--(CH.sub.2).sub.k --N═C═E                        (XII) 
    
     where A and k are as described earlier and E represents oxygen or sulfur. 
     The reaction of the compound of general formula (VIII) with a compound of general formula (XII) may be carried out neat or in the presence of solvents such as THF, ether, 1,4-dioxane, CH 2  Cl 2 , CHCl 3  and EDC and the like in the presence or absence of an aqueous medium. The reaction may be carried out in the presence or absence of inert atmosphere such as N 2 , Ar, or He. The reaction may be effected in the presence of base such as Et 3  N, pyridine, K 2  CO 3 , Na 2  CO 3 , KOH, NaOH and the like or their mixture. The amount of base may range from 1 to 20 equivalents, preferably 1 to 5 equivalents. The reaction may be carried out at a temperature in the range of 0° C. to 180° C., preferably at a temperature in the range 0° C. to 80° C. Duration of the reaction may range from 1 to 48 h, preferably from 1 to 12 h. The amount of compounds of general formula (XII) and (VIII) may range from 1 to 20 equivalents preferably form 1 to 5 equivalents. 
     The compound of the general formula (III) can also be prepared by reacting a compound of general formula (VIII) defined above, with a compound of general formula (XIII) 
     
         A--(CH.sub.2).sub.k --W--T                                 (XIII) 
    
     where A, W and k are as defined earlier and T represents hydrogen in the presence of a carbonylating agent such as carbonyldimidazole, phosgene, diphosgene, triphosgene, diethyl carbonate, ethyl carbonate, dimethyl dithiocarbonate and the like. 
     The reaction of compound of general formula (VIII) with a compound of general formula (XIII) may be carried out neat or in the presence or absence of H 2  O using the solvents such as benzene, toluene, acetone, 1,4-dioxane, THF and, the like. The reaction may be carried out in the presence or absence of an inert atmosphere such as N 2 , Ar, or He. The reaction may be effected in the presence or absence of a base such as LDA, n-BuLi, K 2  CO 3 , Na 2  CO 3 , KOH, NaOH, Et 3  N, pyridine, diisopropylamine and the like. The amount of base may range from 1 to 20 equivalents preferably 1 to 5 equivalents. The reaction may be carried out at a temperature in the range of 0° C. to 180° C., preferably at a temperature in the range of 0° C. to 80° C. Duration of the reaction may range from 1 to 48 h, preferably from 1 to 12 h. The amounts of the compound of general formula (XIII) and carbonylating agent may range from 1 to 20 equivalents, preferably from 1 to 5 equivalents. 
     The present invention provides a process for the preparation of novel azolidinedione derivatives of general formula (I), their tautomeric forms, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts and their pharmaceutically acceptable solvates wherein R 1  and Y together represent a bond and Z represents a sulfur or oxygen atom and all symbols are as defined earlier which comprises: 
     reacting the compound of general formula (III), where G is a CHO group with 2,4-thiazolidinedione or 2,4-oxazolidinedione to yield a compound of general formula (XIV) ##STR29## where A, W, Q, B, D, X, Ar, k, p and Z are as defined earlier and removing the water formed during the reaction by conventional methods. 
     The reaction between the compound of the general formula (III) where G is a CHO group with 2,4-thiazolidinedione or 2,4-oxazolidinedione to yield a compound of general formula (XIV) may be carried out neat in the presence of sodium acetate or in the presence of a solvent such as benzene, toluene, methoxyethanol or mixtures thereof. The reaction temperature may range from 80° C. to 140° C. depending upon the solvents employed and in the range from 80° C. to 180° C. when the reaction is carried out neat in the presence of sodium acetate. Suitable catalyst such as piperidinium acetate or benzoate, sodium acetate or mixtures of catalysts may also be employed. Sodium acetate can be used in the presence of solvent, but it is preferred that sodium acetate is used neat. The water produced in the reaction may be removed, for example, by using Dean Stark water separator or by using water absorbing agents like molecular sieves. Oxazolidine-4-oxo-2-thione may be used instead of 2,4-oxazolidinedione. However, the thio group needs to be converted to oxo group by oxidation using agents such as hydrogen peroxide or peroxyacids like mCPBA. 
     The compound of the general formula (XIV) obtained in the manner described above is reduced by known methods to obtain the compound of general formula (XV) ##STR30## where A, W, Q, B, D, X, Ar, k, p and Z are as defined earlier. The compound of general formula (XV) represents the compound of general formula (I), wherein R 1  is hydrogen and Y is CR 6  where R 6  is hydrogen atom and all other symbols are as defined earlier. 
     The reduction of compound of the formula (XIV) to yield a compound of the general formula (XV) may be carried out in the presence of gaseous hydrogen and a catalyst such as Pd/C, Rh/C, Pt/C, and the like. Mixtures of catalysts may be used. The reaction may also be conducted in the presence of solvents such as dioxane, acetic acid, ethyl acetate and the like. Mixtures of solvents may be used. A pressure between atmospheric pressure and 80 psi may be employed. The catalyst may be 5-10% Pd/C and the amount of catalyst used may range from 50-300% w/w. The reaction may also be carried out by employing metal solvent reduction such as magnesium in methanol or sodium amalgam in methanol. The reaction may also be carried out with alkali metal borohydrides such as LiBH 4 , NaBH 4 , KBH 4 , and the like in the presence of cobalt salt such as CoCl 2  and ligands, preferably bidentated ligands such as 2,2&#39;bipyridyl, 1,10-phenanthroline, bisoximes and the like. 
     The compound of the general formula (XIV) and of general formula (XV) obtained above may be converted into pharmaceutically acceptable salts, or pharmaceutically acceptable solvates by conventional methods. 
     In yet another embodiment of the present invention, the compound of the general formula (I) can also be prepared by reacting a compound of the general formula (IV) defined above with a compound of general formula (XVI) ##STR31## where R 1 , Y, Z and Ar are as defined earlier and R 5  is hydrogen or a nitrogen protecting group which is removed after the reaction. 
     The reaction of compound of general formula (IV) with a compound of general formula (XVI) to produce a compound of general formula (I) may be carried out in the presence of solvents such as THF, DMF, DMSO, DME and the like or mixture thereof. The reaction may be carried out in an inert atmosphere which is maintained by using inert gases such as N 2 , Ar or He. The reaction may be effected in the presence of a base such as alkalis like sodium hydroxide or potassium hydroxide; alkali metal carbonates like sodium carbonate or potassium carbonate; alkali metal hydrides such as sodium hydride; organometallic bases like n-butyl lithium; alkali metal amides like sodamide, or a mixture thereof. Multiple solvents and bases can be used. The amount of base may range from 1 to 5 equivalents, preferably 1 to 3 equivalents. The reaction temperature may be in the range of 0° C. to 120° C., preferably at a temperature in the range of 20° C. to 100° C. The duration of the reaction may range from 0.5 to 24 hours, preferably from 0.5 to 12 hours. 
     The removal of protecting groups may be carried out by conventional methods which include treatment with acid such as, hydrochloric acid, trifluoroacetic acid or bases such as KOH, NaOH, Na 2  CO 3 , NaHCO 3 , K 2  CO 3  and the like or a mixture thereof. These reagents may be used as an aqueous solution or as solutions in alcohols like methanol, ethanol, etc. Deprotection can also be effected by gaseous hydrogen in the presence of a catalyst such as Pd/carbon or conventional transfer hydrogenation methods, when the protecting group is a benzyl or a substituted benzyl group. 
     The compound of general formula (I) can also be obtained by reacting a compound of general formula (VI) with a compound of general formula (XVI). 
     The reaction of compound of general formula (VI) with a compound of general formula (XVI) to produce a compound of general formula (I) may be carried out using suitable coupling agents such as dicyclohexyl urea, triarylphosphine/dialkylazadicarboxylate such as PPh 3  /DEAD, and the like. The reaction may be carried out in the presence of solvents such as THF, DME, CH 2  Cl 2 , CHCl 3 , toluene, acetonitrile, carbontetrachloride and the like. The reaction may be carried out in an inert atmosphere. The inert atmosphere may be maintained by using inert gases such as N 2 , Ar, or He. The reaction may be effected in the presence of DMAP-HOBT and they may be used in the range of 0.05 to 5 equivalents, preferably 0.25 to 3 equivalents. The reaction temperature may be in the range of 0° C. to 100° C., preferably at a temperature in the range of 20° C. to 80° C. The duration of the reaction may range from 0.5 to 48 hours, preferably from 0.5 to 12 hours. 
     In another embodiment of the present invention, the compound of general formula (I), where A, W, Q, B, D, X, k, p and Ar are as defined earlier and R 1  represents hydrogen, Y represents CH and Z represents a oxygen or a sulfur atom can be prepared by the reaction of compound of general formula (XVII) ##STR32## where A, W, Q, B, D, X, k, p and Ar are as defined earlier, J is a halogen atom like chlorine, bromine or iodine or a hydroxy group and R is a lower alkyl group, with thiourea when J is a halogen atom, or with urea when J is a hydroxy group followed by treatment with an acid. 
     The reaction of compound of general formula (XVII) with thiourea or urea is normally carried out in the presence of alcoholic solvent such as methanol, ethanol, propanol, isobutanol, 2-methoxybutanol, etc. or DMSO or sulfolane. The reaction may be conducted at a temperature in the range between 20° C. and the reflux temperature of the solvent used. Bases such as NaOAc, KOAc, NaOMe, NaOEt, etc. can be used. The reaction is normally followed by treatment with a mineral acid such as hydrochloric acid at 20° C. to 100° C. 
     The compound of general formula (XVII) where J is hydroxy group is prepared by the reaction of compound of general formula (XVII) where J is a halogen atom with aqueous alkali at a temperature ranging from 20° C. to 100° C., followed by reesterification of the hydrolysed acid group by conventional methods. 
     The compound of general formula (XVII) where J is a OH group may also be prepared from compound of formula (XVII) where J is a halogen atom by reacting with formamide in the presence of water. The amount of formamide used in the reaction ranges from 0.5 to 1.5 mL and water used ranges from 20 μL to 0.1 mL for one mmol of the halo compound (XVII). The reaction is conducted at a temperature ranging from 80° C. to 180° C., preferably from 120° C. to 150° C., over a period ranging from 1 to 8 hours. 
     The compound of general formula (XVII) where J is a halogen atom can be prepared by the diazotization of the amino compound of the general formula (XVIII) ##STR33## where all symbols are as defined earlier, using alkali metal nitrites followed by treatment with acrylic acid esters in the presence of hydrohalo acids and catalytic amount of copper oxide or copper halide. 
     The compound of general formula (XVIII) can in turn be prepared by the conventional reduction of the novel intermediate (III) where G is NO 2  group and other symbols are as defined earlier. 
     The intermediates of the formula (VI) defined above can be prepared by a process which comprises reacting a compound of general formula (IX) defined earlier with a compound of general formula (XIX). ##STR34## where B, D, X and p are as defined earlier, and R a  is a hydroxy group or a group which can be converted to hydroxy group by conventional methods, such as carboxylic acid group, ester, amide, ether and the like. 
     The reaction of compound of general formula (XIX) with a compound of general formula (IX) to yield a compound of general formula (VI) may be carried out in neat or in the presence of solvents such as DMF, DMSO, CH 3  CN, EtOH, or acetone. The reaction may be carried out in an inert atmosphere. The inert atmosphere is maintained by using inert gases such as N 2 , Ar, or He. The reaction may be effected in the presence of base such as K 2  CO 3 , Na 2  CO 3 , KOH, NaOH, NaH and the like. The amount of base may range from 1 to 20 equivalents, preferably 1 to 10 equivalents. The reaction may be carried out at a temperature in the range 20° C. to 180° C., preferably at a temperature in the range 20° C. to 150° C. Duration of the reaction may range from 1 to 48 hours, preferably from 1 to 12 hours. The amounts of the compound of general formula (IX) and (XIX) may range from 1 to 20 equivalents, preferably from 1 to 5 equivalents. 
     In yet another embodiment of the present invention, the compound of general formula (I), where A, W, Q, B, D, X, Ar, k and p are as defined earlier and Y is a nitrogen atom and Z is an oxygen atom can be prepared by a process which comprises: reaction of novel intermediate of formula (III) where all symbols are as defined earlier, and G represents a CHO group with NH 2  OH.HCl to yield a compound of general formula (III) where G represents CH═NOH group and all symbols are as defined earlier, followed by metal borohydride reduction to yield a compound of general formula (XX) ##STR35## where all symbols are as defined earlier. 
     The reaction of compound of general formula (III), where G is CHO group and other symbols are as defined earlier, with hydroxylamine hydrochloride is carried out in solvents such as ethanol, methanol, THF, dioxane and the like following the conventional method to make oximes. 1 to 10 equivalents of NH 2  OH.HCl may be used, preferably, 2 to 5 equivalents. Bases such as alkali metal acetates or ammonium acetate may be used. Reaction may be carried out in the presence of water. Temperature in the range of 0° C. to reflux temperature of the solvent may be used. The oxime obtained in the manner described above is reduced using reducing agents such as alkali metal borohydrides like sodium borohydride or sodium cyanoborohydride or borane reagents using conventional conditions to yield the compound of general formula (XX). 
     The compound of general formula (XX) in turn is reacted with halocarbonyl isocyanate or alkoxycarbonyl isocyanate to yield a compound of general formula (I) or with KOCN to yield a compound of general formula (III) where G is CH 2  N(OH)CONH 2 , followed by treatment with carbonylating agents such as alkylhaloformate to produce the compound of general formula (I) where A, W, Q, B, D, X, Ar, p and k are as defined earlier, Y represents a nitrogen atom and Z is an oxygen atom. 
     The reaction of compound of general formula (XX) with halocarbonyl isocyanate such as chlorocarbonyl isocyanate or alkoxycarbonyl isocyanate such as ethoxycarbonyl isocyanate may be carried out in inert solvents such as THF, dioxane, etc. at a temperature in the range -15° C. to 50° C. The reaction may be carried out for 0.5 to 12 hours depending on the substrates used for the reaction. 
     Alternatively, the compound of general formula (XX) may be treated with excess of KOCN in organic acids such as acetic acid. Water may be used in the reaction. The reaction may be carried out at a temperature in the range of 20° C. to 120° C. The product isolated in the reaction is further treated with alkyl haloformate such as ethyl chloroformate in the presence of 1 to 10 equivalents of alkali such as sodium hydroxide, potassium hydroxide and the like to obtain compound of general formula (I) where all the symbols are as defined earlier and Y represents nitrogen atom and Z represents oxygen atom. 
     The pharmaceutically acceptable salts are prepared by reacting the compound of formula (I) with 1 to 4 equivalents of a base such as sodium hydroxide, sodium methoxide, sodium hydride, potassium t-butoxide, calcium hydroxide, magnesium hydroxide and the like, in solvents like ether, THF, methanol, t-butanol, dioxane, isopropanol, ethanol, etc. Mixtures of solvents may be used. Organic bases like lysine, arginine, diethanolamine, choline, guanidine and their derivatives etc. may also be used. Alternatively, acid addition salts are prepared by treatment with acids such as hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, phosphoric acid, p-toluenesulphonic acid, methanesulfonic acid, acetic acid, citric acid, maleic acid, salicylic acid, hydroxynaphthoic acid, ascorbic acid, palmitic acid, succinic acid, benzoic acid, benzene sulfonic acid, tartaric acid and the like in solvents like ethyl acetate, ether, alcohols, acetone, THF, dioxane, etc. Mixtures of solvents may also be used. 
     The stereoisomers of the compounds forming part of this invention may be prepared by using reactants or reagents or catalysts in their single enantiomeric form in the process wherever possible or by resolving the mixture of stereoisomers by conventional methods. Some of the preferred methods include use of microbial resolution, resolving the diastereomeric salts formed with chiral acids such as mandelic acid, camphorsulfonic acid, tartaric acid, lactic acid and the like or chiral bases such as brucine, cinchona alkaloids and their derivatives and the like. 
     Various polymorphs of compound of general formula (I) forming part of this invention may be prepared by crystallization of compound of formula (I) under different conditions. For example, using different solvents commonly used or their mixtures for recrystallization; crystallizations at different temperatures; various modes of cooling ranging from very fast to very slow cooling during crystallizations. Polymorphs may also be obtained by heating or melting the compound followed by gradual or fast cooling. The presence of polymorphs may be determined by solid probe NMR spectroscopy, IR spectroscopy, differential scanning calorimetry, powder X-ray data or such other techniques. 
     The present invention also provides a pharmaceutical composition, containing the compounds of the general formula (I), as defined above, their tautomeric forms, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates in combination with the usual pharmaceutically employed carriers, diluents and the like, useful for the treatment and/or prophylaxis of diseases in which insulin resistance is the underlying pathophysiological mechanism such as type II diabetes, impaired glucose tolerance, dyslipidaemia, hypertension, coronary heart disease and other cardiovascular disorders including atherosclerosis; insulin resistance associated with obesity and psoriasis, for treating diabetic complications and other diseases such as polycystic ovarian syndrome (PCOS), certain renal diseases including diabetic nephropathy, glomerulonephritis, glomerular sclerosis, nephrotic syndrome, hypertensive nephrosclerosis, end-stage renal diseases and microalbuminuria as well as certain eating disorders, as aldose reductase inhibitors and for improving cognitive functions in dementia. 
     The pharmaceutical composition may be in the forms normally employed, such as tablets, capsules, powders, syrups, solutions, suspensions and the like, may contain flavourants, sweeteners etc. in suitable solid or liquid carriers or diluents, or in suitable sterile media to form injectable solutions or suspensions. Such compositions typically contain from 1 to 25%, preferably 1 to 15% by weight of active compound, the remainder of the composition being pharmaceutically acceptable carriers, diluents or solvents. 
     A typical tablet production method is exemplified below: 
     
         ______________________________________Tablet Production Example______________________________________a)    1) Active ingredient                    30 g 2) Lactose         95 g 3) Corn starch     30 g 4) Carboxymethyl cellulose                    44 g 5) Magnesium stearate                    1 g                    200 g  for 1000 tablets______________________________________ 
    
     The ingredients 1 to 3 are uniformly blended with water and granulated after drying under reduced pressure. The ingredients 4 and 5 are mixed well with the granules and compressed by a tabletting machine to prepare 1000 tablets each containing 30 mg of active ingredient. 
     
         ______________________________________b)     1) Active ingredient                   30 g  2) Calcium phosphate                   90 g  3) Lactose       40 g  4) Corn starch   35 g  5) Polyvinyl pyrrolidone                   3.5 g  6) Magnesium stearate                   1.5 g                   200 g  for 1000 tablets______________________________________ 
    
     The ingredients 1-4 are uniformly moistened with an aqueous solution of ingredient 5 and granulated after drying under reduced pressure. Ingredient 6 is added and granules are compressed by a tabletting machine to prepare 1000 tablets containing 50 mg of ingredient 1. 
     The compound of the formula (I) as defined above are clinically administered to mammals, including man, via either oral or parenteral routes. Administration by the oral route is preferred, being more convenient and avoiding the possible pain and irritation of injection. However, in circumstances where the patient cannot swallow the medication, or absorption following oral administration is impaired, as by disease or other abnormality, it is essential that the drug be administered parenterally. By either route, the dosage is in the range of about 0.10 to about 200 mg /kg body weight of the subject per day or preferably about 0.10 to about 50 mg/kg body weight per day administered singly or as a divided dose. However, the optimum dosage for the individual subject being treated will be determined by the person responsible for treatment, generally smaller doses being administered initially and thereafter increments made to determine the most suitable dosage. 
     Suitable pharmaceutically acceptable carriers include solid fillers or diluents and sterile aqueous or organic solutions. The active compound will be present in such pharmaceutical compositions in the amounts sufficient to provide the desired dosage in the range as described above. Thus, for oral administration, the compounds can be combined with a suitable solid or liquid carrier or diluent to form capsules, tablets, powders, syrups, solutions, suspensions and the like. The pharmaceutical compositions, may, if desired, contain additional components such as flavorants, sweeteners, excipients and the like. For parenteral administration, the compounds can be combined with sterile aqueous or organic media to form injectable solutions or suspensions. For example, solutions in sesame or peanut oil, aqueous propylene glycol and the like can be used, as well as aqueous solutions of water-soluble pharmaceutically-acceptable acid addition salts or alkali or alkaline earth metal salts of the compounds. The injectable solutions prepared in this manner can then be, administered intravenously, intraperitoneally, subcutaneously, or intramuscularly, with intramuscular administration being preferred in humans. 
    
    
     The invention is explained in detail in the examples given below which are provided by way of illustration only and therefore should not be construed to limit the scope of the invention. 
     Preparation 1 
     1-(Benzyloxycarbonyl)-4-piperidone ##STR36## 
     To a solution of 4-piperidone hydrochloride (79.0 g) in THF and water (4: 1,75 ml), was added 4N NaOH (105 ml) solution followed by benzyl chloroformate (66 ml) at 0° C. The resulting mixture was stirred at the same temperature for 1 h. At the end of this time, the mixture was extracted with ethyl acetate and dried over anhydrous sodium sulphate. The solvent was removed by distillation under reduced pressure to give 135 g (99.5%) of the title compound as a dark thick liquid. 
       1  H NMR (CDCl 3 , 200 MHz): d 2.44 (m, 4H), 3.78 (t, J=6.2 Hz, 4H), 5.2 (s, 2H), 7.4 (bs, 5H). 
     Preparation 2 
     1-(Benzyloxycarbonyl)piperidin-4-carboxylic acid ##STR37## 
     The title compound (18 g, 88.6%) was prepared as a syrupy liquid from isonipecotic acid (10 g) and benzyl chloroformate (17 ml) in a similar manner to that described in preparation 1. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.7 (m, 2H), 1.95 (m, 2H), 2.5 (m, 1H), 2.96 (approx. t, J=11.2 Hz, 2H), 4.1 (approx. d, J=13.2 Hz, 2H), 5.13 (s, 2H), 7.35 (bs, 5H). 
     Preparation 3 
     1-(Benzyloxycarbonyl)-4-piperidinol ##STR38## 
     To a stirred solution of the product (130 g) obtained in preparation 1 in methanol (500 ml) at 0° C., sodium borohydride (25 g) was added and the reaction mixture was stirred at the same temperature for 1 h. At the end of this time, pH was adjusted to 6.5-7.0 using AcOH and the solvent was removed under reduced pressure. The residue was diluted with EtOAc (400 ml) was washed with water, dried (Na 2  SO 4 ) and the solvent was removed under reduced pressure to get 131 g (100%) of the title compound as a syrupy liquid. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.5 (m,2H), 1.85 (m,2H), 3.15 (m,2H), 3.9 (m, 3H), 5.11 (s, 2H), 7.35 (bs, 5H). 
     Preparation 4 
     (2S)-1-(Benzyloxycarbonyl)-2-hydroxymethyl pyrolidine ##STR39## 
     To a stirred solution of 1(benzyloxycarbonyl)-L-proline (15 g) in tetrahydrofuran (150 ml) at 0° C., borane-methylsulfide complex (9 ml, 95% in dimethyl sulfide) was added and the reaction mixture was stirred at room temperature for 8 h. At the end of this time the reaction was quenched with 10% AcOH in methanol and the solvent was removed under reduced pressure. The crude product thus obtained was diluted with CHCl 3  and washed with water, dried (CaCl 2 ) and the solvent was removed under reduced pressure to get 11.5 g (81%) of the title compound as a thick liquid. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.5-2.2 (m, 4H), 3.3-3.8 (m, 4H), 4.0 (m, 1H), 5.15 (s, 2H), 7.36 (bs, 5H). 
     Preparation 5 
     1-(Benzyloxycarbonyl)-4-hydroxymethyl piperidine ##STR40## 
     The title compound (15 g, 99%) was prepared as a thick liquid from 1-(benzyloxycarbonyl)piperidine-4-carboxylic acid (16 g), obtained in preparation 2, by a similar procedure to that described in preparation 4. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.15 (m, 2H), 1.7 (m, 3H), 2.78 (approx. t, J=12.6 Hz, 2H), 3.5 (d, J=6.2 Hz, 2H), 4.21 (approx. d, J=12.6 Hz, 2H), 5.12 (s, 2H), 7.35 (bs, 5H). 
     Preparation 6 
     1-(Benzyloxycarbonyl)piperidin-4-methanesulfonate ##STR41## 
     To an ice cooled solution of the product (130 g) obtained in preparation 3 and triethylamine (115 ml) in dichloromethane (300 ml) was added methanesulfonyl chloride (52 ml). The mixture was stirred at room temperature for 1 h. At the end of this time, the reaction mixture was washed with aqueous NaHCO 3  solution followed by water, dried (CaCl 2 ) and concentrated to get 172 g (99%) of the title compound as a thick liquid. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.7-2.1 (m, 4H), 3.0 (s, 3H), 3.45 (m, 2H), 3.75 (m, 2H), 4.9 (m, 1H), 5.13 (s, 2H), 7.45 (bs, 5H). 
     Preparation 7 
     1-(Benzyloxycarbonyl)-(2S)-pyrrolidin-2-ylmethyl methanesulfonate ##STR42## 
     The title compound (13 g, 97%) was prepared from 1-(benzyloxycarbonyl)-(2S)-2-hydroxymethyl pyrrolidine (10 g), obtained in preparation 4 and methanesulfonyl chloride (7.2 ml) by a similar procedure to that used in preparation 6. 
       1  H NMR (DMSO-d 6 , 200 MHz): d 1.65-2.1 (m, 4H), 3.16 (s, 3H), 3.35 (bs, 2H), 4.03 (m, 1H), 4.24 (m, 2H), 5.1 (s, 2H), 7.37 (bs, 5H). 
     Preparation 8 
     1-(Benzyloxycarbonyl)piperidin-4-ylmethyl methanesulfonate ##STR43## 
     The title compound (19.6 g, 100%) was prepared from 1-(benzyloxycarbonyl)-4-hydroxymethyl piperidine (15 g), obtained in preparation 5, and methanesulfonyl chloride (9.3 ml) by a similar procedure to that used in preparation 6. mp: 62°-64° C. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.25 (m, 2H), 1.7-2.1 (m, 3H), 2.8 (t, J=12.4 Hz, 2H), 3.01 (s, 3H), 4.06 (d, J=6.6 Hz, 2H), 4.24 (approx. d, J=11.4 Hz, 2H), 5.13 (s, 2H), 7.36 (bs, 5H). 
     Preparation 9 
     4- 1-(Benzyloxycarbonyl)piperidin-4-yloxy!benzaldehyde ##STR44## 
     To a mixture of 1-(benzyloxycarbonyl)piperidin-4-methanesulfonate (172 g) obtained in preparation 6 and 4-hydroxybenzaldehyde (80 g) in dry DMF (1 L), K 2  CO 3  (151 g) was added and the mixture was stirred at 80° C. for 2 h. At the end of this time, the reaction mixture was cooled, added water and extracted with EtOAc (2×500 ml). The EtOAc extract was washed with 5% Na 2  CO 3  solution, followed by brine and dried over anhydrous sodium sulfate. The solvent was then removed by distillation under reduced pressure to give 175 g of the crude compound. This was chromatographed on silica gel using 5 to 30% (gradient elution) ethyl acetate in petroleum ether to afford 110 g (59%) of the pure title compound. mp: 70°-72° C. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.75-2.10 (m, 4H), 3.50 (m, 2H), 3.75 (m, 2H), 4.65 (m, 1H), 5.15 (s, 2H), 7.0 (d, J=8.8 Hz, 2H), 7.36 (bs, 5H), 7.83 (d, J=8.8 Hz, 2H), 9.88 (s, 1H). 
     Preparation 10 
     4- 1-(Benzyloxycarbonyl)-(2S)-pyrrolidin-2-ylmethoxy!benzaldehyde ##STR45## 
     The title compound (4.5 g, 41%) was prepared as a gummy solid from 1-(benzyloxycarbonyl)-(2S)-pyrrolidine-2-ylmethyl methanesulfonate (10 g) obtained in preparation 7 and 4-hydroxybenzaldehyde (5.8 g) in a similar manner to that described in preparation 9. 
       1  H NMR (CDCl 3 , 200 MHz): d 2.05 (m, 4H), 3.49 (bs, 2H), 3.8-4.4 (m, 3H), 5.16 (s, 2H), 7.0 (m, 2H), 7.36 (bs, 5H), 7.8 (m, 2H), 9.87 (s, 1H). 
     Preparation 11 
     4- 1-(Benzyloxycarbonyl)piperidin-4-ylmethoxy!benzaldehyde ##STR46## 
     The title compound (19.4 g) was prepared from 1-(benzyloxycarbonyl)piperidin-4-ylmethyl methanesulfonate (18 g) obtained in preparation 8 and 4-hydroxy benzaldehyde (10 g) in a similar manner to that described in preparation 9. mp: 76°-78° C. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.8 (m, 2H), 1.6-2.3 (m, 3H), 2.85 (m, 2H), 3.85 (d, J=4.6 Hz, 2H), 4.35 (m, 2H), 5.13 (s, 2H), 6.97 (d, J=8.6 Hz, 2H), 7.35 (bs, 5H), 7.82 (d, J=8.6 Hz, 2H), 9.87 (s, 1H). 
     Preparation 12 
     4- 1-(Fluoren-9-ylmethoxycarbonyl)piperidin-4-yloxy!benzaldehyde ##STR47## 
     The title compound (1.0 g, 20%) was prepared from 4- piperin-4-yloxy!benzaldehyde (2.5 g) and 9-fluorenylmethyl chloroformate (3.2 g) in a similar manner to that described in preparation 1. mp: 106°-108° C. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.84 (m, 4H), 3.5 (m, 2H), 3.68 (m, 2H), 4.26 (t, J=6.4 Hz, 1H), 4.47 (d, J=6.8 Hz, 2H), 4.65 (m, 1H), 7.01 (d, J=8.4 Hz, 2H), 7.2-7.95 (m, 10H), 9.9 (s, 1H). 
     Preparation 13 
     4- 1-(Phenoxycarbonyl)piperidin-4-yloxy!benzaldehyde ##STR48## 
     To a stirred mixture of phenol (0.83 g) and 4-(piperidin-4-yloxy)benzaldehyde (2 g) in dry benzene (20 ml), 1,1&#39;-carbonyldiimidazole (1.58 g) was added and the reaction mixture was stirred at 80° C. for 12 h. At the end of this time, the reaction mixture was diluted with EtOAc, washed with H 2  O, dried (Na 2  SO 4 ) and the solvent was removed under reduced pressure. The crude product was chromatographed on silica gel using 5 to 15% (gradient elution) ethyl acetate in petroleum ether to afford 1.9 g (61%) of the title compound. 
       1  H NMR (CDCl 3 , 200 MHz): d 2.0 (m, 4H), 3.8 (m, 4H), 4.7 (m, 1H), 6.9-7.5 (m, 7H), 7.87 (d, J=8.6 Hz, 2H), 9.92 (s, 2H). 
     Preparation 14 
     4- 1-(Anilinocarbonyl)piperidin-4-yloxy!benzaldehyde ##STR49## 
     To an ice cooled solution of 4-(piperidin-4-yloxy)benzaldehyde (2 g) and triethylamine (1.35 ml) in tetrahydrofuran (20 ml) was added phenyl isocyanate (1.3 ml). The mixture was stirred at room temperature for 3 h. At the end of this time, the reaction mixture was diluted with EtOAc, washed with aqueous NaHCO 3  solution followed by water, dried (Na 2  SO 4 ) and concentrated to get 3.1 g (99%) of the title product as a gummy solid. 
       1  H NMR (DMSO-d 6 , 200 MHz): d 1.7 (m, 2H), 2.1 (m, 2H), 3.3 (m, 2H), 3.9 (m, 2H), 4.4, 4.8 (2m, 1H), 7.0 (m, 2H), 7.3 (m, 4H), 7.5 (m, 2H), 7.87 (d, J=8.4 Hz, 2H), 8.65 (s, exchangeable with D 2  O, 1H), 9.88 (s, 1H). 
     Preparation 15 
     4- 1-(Benzylaminocarbonyl)piperidin-4-yloxy)benzaldehyde ##STR50## 
     The title compound (0.2 g, 80%) was prepared as a white solid from 4-(piperidin-4-yloxy)benzaldehyde (0.25 g) and benzyl isocyanate (0.084 ml), in a similar manner to that described in preparation 14. 
       1  H NMR (DMSO-d 6 , 200 MHz): d 1.6-2.2 (m, 4H), 3.3 (m, 2H), 3.65 (m, 2H), 4.4 (m, 2H), 4.25, 4.65 (2m, 1H), 7.0 (d, J=8.8 Hz, 2H), 7.3 (m, 5H), 7.3 (d, J=8.6 Hz, 2H), 9.88 (s, 1H). 
     EXAMPLE 1 
     5- 4- 1(Benzyloxycarbonyl)piperidin-4-yloxy!phenyl methylene!thiazolidine-2,4-dione ##STR51## 
     A solution of 4- 1-(benzyloxycarbonyl)piperidin-4-yloxy!benzaldehyde (44 g) obtained in preparation 9 and 2,4-thiazolidinedione (15.2 g) in toluene (400 ml) containing piperidine (1.6 g) and benzoic acid (2 g) was heated at reflux for 1 h using Dean Stark apparatus. The reaction mixture was cooled and filtered to obtain pale yellow solid (56 g, 100%). 
     Preparation of Polymorphs 
     Form IV 
     The crude product (28 g) obtained above was chromatographed on silica gel using 4% methanol in benzene to afford the title compound as a pale yellow solid (24 g, 85%). mp 178.25° C. (DSC). 
       1  H NMR (CDCl 3 , 200MHz): d 1.7-2.1 (m, 4H), 3.55 (m, 2H), 3.75 (m, 2H), 4.6 (m, 1H), 5.16 (s, 2H), 7.0 (d, J=8.8 Hz, 2H), 7.38 (bs, 5H), 7.46 (d, J=8.8 Hz, 2H), 7.82 (s, 1H). 
     Form III 
     The crude product (28 g) obtained in example 1 was recrystallized from a mixture of ethyl acetate and Pet. Ether (4:1) to get the title compound as a pale yellow solid (22 g, 78%). mp 189.18° C.(DSC). 
       1  H NMR (CDCl 3 , 200 MHz): identical to that of Form IV 
     Form II 
     The product (0.5 g) obtained above as Form III was dissolved in CHCl 3 , filtered through a cotton plug and the filtrate was evaporated under reduced pressure below 40° C. to get Form II as a pale yellow solid (0.5 g, 100%). mp 189.98° C. 
       1  H NMR (CDCl 3 , 200 MHz): identical to that of Form IV. 
     Form I 
     The compound (0.5 g) obtained in Form III is taken in a single necked round bottom flask equipped with a nitrogen inlet and was heated at 200° C. until the solid melted. The melt was cooled in ice to get a yellow solid (0.5 g, 100%). mp 190.45° C. 
       1  H NMR (CDCl 3 , 200 MHz): identical to that of Form IV. 
     EXAMPLE 2 
     5- 4- 1-(Benzyloxycarbonyl)piperidin-4-yloxy!phenyl methyl!thiazolidine-2,4-dione ##STR52## 
     To a stirred suspension of the product (4 g) obtained in example 1 in methanol (40 ml) at room temperature, magnesium turnings (3.8 g) were added and the reaction mixture was stirred at the same temperature for 1 h. The reaction mixture was added to ice water (20 ml), the pH was adjusted to 6.5-7.0 using 10% aqueous hydrochloric acid and the solution was extracted with chloroform (3×100 ml). The combined organic extract was washed with H 2  O, dried (CaCl 2 ) and the solvent was removed under reduced pressure. The residual mass was chromatographed on silica gel using 0.4% methanol in chloroform to give 2.4 g (68%) of the title compound. mp 72°-74° C. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.65-2.05 (m, 4H), 3.1 (dd, J=14.2 and 9.4 Hz, 1H), 3.5 (m, 3H), 3.75 (m, 2H) 4.5 (m, 2H), 5.15 (s, 2H), 6.85 (d, J=8.4 Hz, 2H), 7.14 (d, J=8.4 Hz, 2H), 7.37 (bs, 5H). 
     EXAMPLE 3 
     5- 4- 1-(Benzyloxycarbonyl)piperidin-4-ylmethoxy!phenyl methylene!thiazolidine-2,4-dione ##STR53## 
     The title compound (24 g, 100%) was prepared from 4- 1-(benzyloxycarbonyl)piperidin-4-ylmethoxy!benzaldehyde (18 g), obtained in preparation 11, by a similar procedure to that described in example 1. 
     Preparation of Polymorphs 
     Form I 
     The crude product (24 g) obtained above was chromatographed on silicagel using 0-5% methanol in CHCl 3  (gradient elution) to get the title compound as a pale yellow solid (20 g, 83%). mp 158.3° C. (DSC). 
       1  H NMR (CDCl 3 , 200 MHz): d 1.3 (m, 2H), 1.75-2.15 (m, 3H), 2.83 (approx. t, J=12.4 Hz, 2H), 3.85 (d, J=6.2 Hz, 2H), 4.25 (approx. d, J=12.4 Hz, 2H), 5.14 (s, 2H), 6.96 (d, J=8.8 Hz, 2H), 7.35 (bs, 5H), 7.44 (d, J=8.8 Hz, 2H), 7.8 (s, 1H), 9.1 (bs, exchangeable with D 2  O, 1H). 
     Form II 
     The product (0.5 g) obtained above was dissolved in CHCl 3 , filtered through a cotton plug and the filtrate was evaporated under reduced pressure to get Form II as pale yellow solid (0.5 g, 100%). mp 153.97° C. (DSC). 
       1  H NMR (CDCl 3 , 200 MHz): identical to that of Form 1. 
     EXAMPLE 4 
     5- 4- 1-(Benzyloxycarbonyl)piperidin-4-ylmethoxy!phenyl methyl!thiazolidine-2,4-dione ##STR54## 
     5- 4- 1-(Benzyloxycarbonyl)piperidin-4-ylmethoxy!phenyl methylene!thiazolidine-2,4-dione (4.0 g), obtained in example 3 was dissolved in 1,4-dioxane (40 ml) and was reduced with hydrogen (50 Psig) in the presence of 10% palladium on charcoal (4 g) at ambient temperature until hydrogen uptake ceased. The solution was filtered through a bed of celite, the filter pad was washed exhaustively with dioxane and the combined filtrate was evaporated to dryness under reduced pressure. The crude compound was chromatographed on silica gel using 0.5% MeOH in CHCl 3  to give 2.1 g (53%) of the title compound. mp: 54°-56° C. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.25 (m, 2H), 1.7-2.1 (m, 3H), 2.83 (t, J=12.3 Hz, 2H), 3.06 (dd, J=14.2 and 9.8 Hz, 1H), 3.45 (dd, J=14.2 and 4.0 Hz, 1H), 3.8 (d, J=6.0 Hz, 2H), 4.24 (approx. d, J=12.4 Hz, 2H), 4.45 (dd, J=9.4 and 3.8 Hz,1H), 5.13 (s, 2H), 6.81 (d, J=8.4 Hz, 2H), 7.13 (d, J=8.4 Hz, 2H), 7.36 (bs, 5H). 
     EXAMPLE 5 
     5- 4- 1-(Benzyloxycarbonyl)-(2S)-pyrrolidin-2-ylmethoxy!phenyl methylene!thiazolidine-2,4-dione ##STR55## 
     The title compound (2.7 g, 70%) was prepared from 4- 1-(benzyloxycarbonyl)-(2S)-pyrrolidin-2-ylmethoxy!benzaldehyde (3 g), obtained in preparation 10, by a similar procedure to that described in example 1. 
     Preparation of Polymorphs 
     Form III 
     The crude product (0.5 g) was triturated with Pet. ether, filtered and dried to get a pale yellow solid (0.48 g, 96%). mp. 178.76° C. (DSC). 
       1  H NMR (CDCl 3 , 200 MHz): d 2.0 (m, 4H), 3.49 (bs, 2H), 3.75-4.3 (m, 3H), 5.16 (s, 2H), 6.9 (m, 2H), 7.35 (m, 7H), 7.69 (s, 1H). 
     Form II 
     The product (0.5 g) obtained in Form III was dissolved in CHCl 3 , filtered through a cotton plug and the filtrate was evaporated under reduced pressure to get a pale yellow solid. mp. 179.86° C. (DSC). 
       1  H NMR (CDCl 3 , 200 MHz): identical to that of Form III. 
     Form I 
     The crude product (2 g) obtained in example 5 was recrystallized from ethyl acetate and Pet. Ether (4:1) to get a yellow crystalline solid. mp. 182.82° C. (DSC). 
       1  H NMR (CDCl 3 , 200 MHz): identical to that of Form III. 
     EXAMPLE 6 
     5- 4-  1-(Benzyloxycarbonyl)-(2S)-pyrrolidin-2-ylmethoxy!phenyl methyl!thiazolidine-2,4-dione ##STR56## 
     The title compound (3.5 g, 87%) was prepared as a hygroscopic solid from 5- 4- 1-(benzyloxycarbonyl)-(2S)-pyrrolidin-2-ylmethoxy!phenyl methylene!thiazolidine-2,4-dione (4 g), obtained in example 5, by a similar procedure to that described in example 4. 
       1  H NMR (CDCl 3 , 200 MHz): d 2.0 (m, 4H), 3.06 (m, 1H), 3.46 (m, 3H), 3.7-4.3 (m, 3H), 4.45 (dd, J=9.2 and 3.4 Hz, 1H), 5.15 (s, 2H), 6.8 (m,2H), 7.1 (m, 2H), 7.35 (bs, 5H), 9.2 (bs, exchangeable with D 2  O, 1H). 
     EXAMPLE 7 
     5- 4- 1-(Fluoren-9-ylmethoxycarbonyl)piperidin-4-yloxy!phenyl methylene!thiazolidine-2,4-dione ##STR57## 
     The title compound (1.2 g, 61%) was prepared from 4- 1- fluoren-9-ylmethoxycarbonyl)piperidin-4-yloxy!benzaldehyde (1.6 g) obtained in preparation 12, by a similar procedure to that described in example 1. mp: 184.7° C. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.8 (m, 4H), 3.45 (m, 2H), 3.7 (m, 2H), 4.25 (t, J=6.6 Hz, 1H), 4.46 (d, J=6.8 Hz, 2H), 4.6 (m, 1H), 7.0 (d, J=8.6 Hz, 2H), 7.2-7.9 (m, 11H). 
     EXAMPLE 8 
     5- 4- 1-(Phenoxycarbonyl)piperidin-4-yloxy!phenyl methylene!thiazolidine-2,4-dione ##STR58## 
     The title compound (1.5 g, 88%) was prepared from 4- 1-(phenoxycarbonyl)piperidin-4-yloxy!benzaldehyde (1.8 g) obtained in preparation 13, by a similar procedure to that described in example 1. mp : 224°-226° C. 
       1  H NMR (CDCl 3 , 200 MHz): d 1.7 (m, 2H), 2.0 (m, 2H), 3.5 (m, 2H), 3.9 (m, 2H), 4.8 (m, 1H), 7.2 (m, 5H), 7.4 (m, 2H), 7.57 (d, J=8.6 Hz, 2H), 7.76 (s, 1H), 12.5 (bs, exchangeable with D 2  O, 1H). 
     EXAMPLE 9 
     5- 4- 1-(Anilinocarbonyl)piperidin-4-yloxy!phenyl methylene!thiazolidine-2,4-dione ##STR59## 
     The title compound (1.45 g, 74%) was prepared as a pale yellow solid from 4- 1-(anilino carbonyl)piperidin-4-yloxy!benzaldehyde (1.5 g) obtained in preparation 14, by a similar procedure to that described in example 1. 
       1  H NMR (DMSO-d 6 , 200 MHz): d 1.7 (m, 2H), 2.1 (m, 2H), 3.3 (m, 2H), 3.9 (m, 2H), 4.7 (m, 1H), 6.95 (m, 1H), 7.3 (m, 4H), 7.46 (d, J=8.2 Hz, 2H), 7.58 (d, J=8.6 Hz, 2H), 7.76 (s, 1H), 12.6 (bs, exchangeable with D 2  O, 1H). 
     EXAMPLE 10 
     5- 4- 1-(Benzylaminocarbonyl)piperidin-4-yloxy!phenyl methylene!thiazolidine-2,4-dione ##STR60## 
     The title compound (0.35 g, 36%) was prepared as a pale yellow solid from 4- 1-(benzyl aminocarbonyl)piperidin-4-yloxy!benzaldehyde (0.75 g) obtained in preparation 15, by a similar procedure to that described in example 1. 
       1  H NMR (DMSO-d 6 , 200 MHz): d 1.7 (m, 2H), 2.0 (m, 2H), 3.3 (m, 2H), 3.7 (m, 2H), 4.4 (s, 2H), 4.6 (m, 1H), 7.0 (d, J=8.8 Hz, 2H), 6.9 (m, 5H), 7,46 (d, J=9.8 Hz, 2H), 7.7 (s, 1H), 12.2 (bs, exchangeable with D 2  O, 1H). 
     EXAMPLE 11 
     5- 4- 1(Benzylaminocarbonyl)piperidin-4-yloxy!phenyl methyl!thiazolidine-2,4-dione ##STR61## 
     The title compound (0.1 g, 49%) was prepared as a white solid from 5- 4- 1-(benzylamino carbonyl)piperidin-4-yloxy!phenyl methylene!thiazolidine-2,4-dione (0.2 g), obtained in example 10, by a similar procedure to that described in example 4. 
       1  H NMR(DMSO-d 6 , 200 MHz): d 1.5 (m, 2H), 1.9 (m, 2H), 2.95-3.4 (m, 4H), 3.7 (m, 2H), 4.25 (s, 2H), 4.5 (m, 1H), 4.86 (dd, J=8.8 and 4.2 Hz, 1H), 6.91 (d, J=8.2 Hz, 2H), 7.2 (m, 7H), 12.0 (bs, exchangeable with D 2  O, 1H). 
     Mutation in colonies of laboratory animals and different sensitivities to dietary regimens have made the development of animal models with non-insulin dependent diabetes associated with obesity and insulin resistance possible. Genetic models such as db/db and ob/ob (See Diabetes, (1982) 31(1): 1-6) in mice and fa/fa and zucker rats have been developed by the various laboratories for understanding the pathophysiology of disease and testing the efficacy of new antidiabetic compounds (Diabetes, (1983)32: 830-838; Annu. Rep. Sankyo Res. Lab. (1994). 46: 1-57). The homozygous animals, C57 BL/KsJ-db/db mice developed by Jackson Laboratory, US, are obese, hyperglycemic, hyperinsulinemic and insulin resistant (J. Clin. Invest., (1990) 85: 962-967), whereas heterozygous are lean and normoglycemic. In db/db model mouse progressively develops insulinopenia with age, a feature commonly observed in late stages of human type II diabetes when blood sugar levels are insufficiently controlled. The state of pancreas and its course vary according to the models. Since this model resembles that of type II diabetes mellitus, the compounds of the present invention were tested for blood sugar and triglycerides lowering activities. 
     The compounds of the present invention showed blood sugar and triglycerides lowering activities through improved insulin resistance. This was demonstrated by the following in vivo experiments. 
     Male C57BL/KsJ-db/db mice of 8 to 14 weeks age, having body weight range of 35 to 60 grams, procured from the Jackson Laboratory, USA, were used in the experiment. The mice were provided with standard feed (National Institute of Nutrition, Hyderabad, India) and acidified water, ad libitum. The animals having more than 300 mg/dl blood sugar were used for testing. The number of animals in each group was 4. 
     The random blood sugar ad triglyceride levels were measured by collecting blood (100 μl) through orbital sinus, using heparinized capillary in tubes containing EDTA which was centrifuged to obtain plasma. The plasma glucose and triglyceride levels were measured through spectrometrically, by glucose oxidase and glycerol-3-PO 4  oxidase/peroxidase enzyme (Dr. Reddy&#39;s Lab. Diagnostic Division Kits, Hyderabad, India) methods respectively. On 6th day the blood samples were collected one hour after administration of test compounds/vehicle for assessing the biological activity. 
     Test compounds were suspended on 0.25% carboxymethyl cellulose and administered to test group at a dose of 30 mg to 200 mg/kg through oral gavage daily for 6 to 9 days. The control group received vehicle (dose 10 ml/kg). Troglitazone (100 mg/kg, daily dose) was used as a standard drug which showed 28% reduction in random blood sugar level on 6th day. 
     The blood sugar and triglycerides lowering activities of the test compound was calculated according to the formula: ##EQU1## ZC=Zero day control group value DC=Zero day treated group value 
     TC=Control group value on test day 
     DT=Treated group value on the test day 
     No adverse effects were observed for any of the mentioned compounds of invention in the above test. 
     
         ______________________________________               Reduction in Blood                             TriglycerideCompound Dose (mg/kg)               Glucose Level (%)                             Lowering (%)______________________________________Example 1     200*      62            70    100        59            29     30        47            --Example 3    100        35            56Example 5     30        30             5Example 10     30        37             6______________________________________ *Treated for nine days 
    
     The experimental results from the db/db mice suggest that the novel compounds of the present invention also possess therapeutic utility as a prophylactic or regular treatment for obesity, cardiovascular disorders such as hypertension, hyperlipidaemia and other diseases; as it is known from the literature that such diseases are interrelated to each other.