Patent ID: 7691889

Claim:
A compound of formula (I) and its pharmaceutically acceptable salts wherein, A is either hydrogen or fluorine, B is either hydrogen or fluorine, wherein one of A and B is hydrogen and the other is fluorine, R 1 is a group of formula, wherein, Q is either an alkyl group of two carbon atoms, an alkene group of two carbon atoms or an alkyne group of two carbon atoms Y is oxygen; Ar is a substituted phenyl ring or a substituted pyridine ring of formula or Ar is a five membered ring of formula or Ar is a fused bicyclic phenyl or pyridine ring of formula wherein, M is either CH or N Z is CH, NH, O, or S, X is a group selected from OR 4 , NR 4 R 5 , NO 2 , SR 4 , SOOR 4 , SOONR 4 R 5 , F, Cl, Br or I, wherein R 4 is as defined hereinbefore, and R 3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or branched; cycloalkyl of 3-7 carbon atoms; CHO, —COOH, —COOR 4 ; —COCR 4 ; CN; aryl or heteroaryl; wherein, R 4 is an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms; R 5 is hydrogen or R 4 R 2 is selected from the groups shown below, and the corresponding N-oxides thereof; Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, SO 2 , or CH 2 .