Patent ID: 6939854

Claim:
A compound of formula or a stereoisomer or a pharmaceutically acceptable salt thereof, wherein: R 1 is —CH 2 CH 2 —Ar, —CH 2 CH 2 CH 2 —Ar, —CH 2 CH 2 CH 2 CH 2 —Ar, —CH 2 CH 2 CH 2 CH 2 CH 3 , —CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 , —CH 2 CH 2 CH 2 C(CH 3 ) 2 , —CH 2 CH 2 CH 2 C(CH 2 CH 3 ) 2 , or —CH 2 CH 2 CH 2 -cyclobutyl, wherein Ar is phenyl, naphthyl, or biphenyl, and phenyl is unsubstituted or substituted with 1-2 substituents selected from the group consisting of halo, C 1 -C 4 alkyl, hydroxy, methoxy, phenoxy, and trifluoromethyl.