Patent ID: 8212057

Claim:
A compound of formula (I): their tautomeric forms, their stereoisomers, their pharmaceutically acceptable salts, wherein R 2 and R 3 represent hydrogen, and R 1 is ethyl, R 4 may be same or different, and represent hydrogen, haloalkyl, perhaloalkyl, nitro, cyano, formyl, or substituted or unsubstituted groups selected from linear or branched (C 1 -C 6 )alkyl, linear or branched (C 2 -C 6 )alkenyl, linear or branched (C 2 -C 6 )alkynyl, (C 3 -C 7 )cycloalkyl, (C 3 -C 7 )cycloalkenyl, aryl, aralkyl, heterocyclyl, heteroaryl, heterocyclyl(C 1 -C 6 )alkyl, heteroar(C 1 -C 6 )alkyl, acyl, acyloxy, carboxylic acid esters and amides, hydroxyalkyl, aminoalkyl, mono-substituted or di-substituted aminoalkyl, alkoxyalkyl, aryloxyalkyl, aralkoxyalkyl, (C 1 -C 6 )alkylthio, thio(C 1 -C 6 )alkyl, arylthio, sulfenyl and sulfonyl groups, sulfonic acid groups; n represents an integer 2, W represents O; Ar represents a substituted or unsubstituted divalent single or fused aromatic, heteroaromatic group; R 5 and R 6 represent both hydrogen or together represent a bond; X, Y, Z, each independently represents O; R 7 represents hydrogen, substituted or unsubstituted linear or branched (C 1 -C 12 )alkyl groups; R 8 represents hydrogen, substituted or unsubstituted groups selected from linear or branched (C 1 -C 6 )alkyl.