Patent ID: 7781468

Claim:
A compound of formula I, racemate, optically active isomer, or pharmaceutically acceptable salt thereof, wherein R 1 is selected from hydrogen, C 1 -C 4 straight or branched alkyl; R 2 and R 3 are independently selected from hydrogen, halogen, C 1 -C 4 straight or branched alkyl; Ar is selected from mono-, di-, or tricyclic aromatic carbocyclic ring or heterocyclic ring containing 1 to 4 heteroatoms selected from a group consisting of O, S and N, wherein each single ring is 5- or 6-membered ring, and said ring may be unsubstituted or substituted with 1 to 5 of the following groups: halogen, nitro, hydroxy, hydroxymethyl, trifluoromethyl, trifluoromethoxy, C 1 -C 6 straight or branched alkyl, C 2 -C 6 straight or branched alkenyl, C 1 -C 4 alkoxy, C 2 -C 4 alkenoxy, phenoxy, benzyloxy, carboxyl or amino; Y is hydrogen or halogen; and n is an integer from 1 to 4.