Patent ID: 8629277

Claim:
A compound of formula I, wherein, R 1 is selected from hydroxy, (C 1 -C 12 )-alkoxy or aryloxy; R 2 is selected from hydroxy, nitro, (C 1 -C 12 )-alkoxy, aryloxy, NH—SO 2 —(C 1 -C 12 )-alkyl, NH—SO 2 -aryl and NR a R b ; R 3 is selected from hydrogen, (C 1 -C 12 )-alkyl, (C 3 -C 12 )-cycloalkyl, aralkyl, aryl or heterocyclyl; and n is an integer from 0-3; wherein, (C 1 -C 12 )-alkyl is unsubstituted or substituted with one or more groups selected from halogen, hydroxy, cyano, nitro, (C 1 -C 12 )-alkoxy, unsubstituted or substituted aryl, unsubstituted or substituted heterocyclyl, COOR a , C(O)R a , SR a and C(O)NR a R b ; alkyl of (C 1 -C 12 )-alkoxy is unsubstituted or substituted with one or more groups selected from halogen, hydroxy, cyano, nitro, unsubstituted or substituted aryl, unsubstituted or substituted heterocyclyl, COOR a , C(O)R a , SR a and C(O)NR a R b ; (C 3 -C 12 )-cycloalkyl is unsubstituted or substituted with one or more groups selected from halogen, hydroxy, cyano, nitro, unsubstituted or substituted (C 1 -C 12 )-alkyl, (C 1 -C 12 )-alkoxy, unsubstituted or substituted aryl, unsubstituted or substituted heterocyclyl, COOR a , C(O)R a , SR a , NR a R b and C(O)NR a R b ; aryl is unsubstituted or substituted with one or more groups selected from halogen, hydroxy, cyano, nitro, (C 1 -C 12 )-alkyl, (C 2 -C 12 )-alkenyl, (C 2 -C 12 )-alkynyl, (C 1 -C 12 )-alkoxy, unsubstituted or substituted heterocyclyl, COOR a , C(O)R a , SR a , NR a R b and C(O)NR a R b ; aryl of aryloxy is unsubstituted or substituted with one or more groups selected from halogen, hydroxy, cyano, nitro, unsubstituted or substituted (C 1 -C 12 )-alkyl, (C 2 -C 12 )-alkenyl, (C 2 -C 12 )-alkynyl, unsubstituted or substituted heterocyclyl, COOR a , C(O)R a , SR a , NR a R b and C(O)NR a R b ; aryl of aralkyl is unsubstituted or substituted with one or more groups selected from halogen, hydroxy, cyano, nitro, unsubstituted or substituted (C 1 -C 12 )-alkyl, (C 2 -C 12 )-alkenyl, (C 2 -C 12 )-alkynyl and unsubstituted or substituted heterocyclyl; heterocyclyl is unsubstituted or substituted with one or more groups selected from halogen, hydroxy, cyano, nitro, unsubstituted or substituted (C 1 -C 12 )-alkyl, (C 1 -C 12 )-alkoxy, unsubstituted or substituted aralkyl, unsubstituted or substituted aryl, COOR a , C(O)R a , SR a , NR a R b , (C 1 -C 12 )-alkyl-NR a R b and C(O)NR a R b ; and R a and R b are independently selected from hydrogen, (C 1 -C 12 )-alkyl, aralkyl, aryl or heterocyclyl; with a proviso that when n is 0, R 3 is other than aryl or heterocyclyl; or a stereoisomer, tautomer, pharmaceutically acceptable salt or pharmaceutically acceptable polymorph thereof.