Patent ID: 7544687

Claim:
A compound of formula I, racemate, optically active isomer, or pharmaceutically acceptable salt thereof, wherein: R 1 and R 2 are independently hydrogen, or C 1-4 straight or branched alkyl; R 3 is Ar 1 or —SO 2 Ar 1 ; Ar and Ar 1 are phenyl ring which is unsubstituted or optionally 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.