Patent ID: 8242157

Claim:
A compound of formula (I), wherein a is an integer form 0 to 1; R 0 is selected from the group consisting of fluoro and methyl; R 2 is hydrogen; R 1 is selected from the group consisting of methyl and ethyl; alternatively R 2 and R 1 are taken together as R 3 is selected from the group consisting of methyl, phenyl, 4-fluorophenyl and 4-chlorophenyl; R 4 is selected from the group consisting of benzyl, 4-fluoro-benzyl, 3,4-difluoro-benzyl, 3-trifluoromethyl-benzyl, 4-trifluoromethyl-benzyl, 4-difluoromethoxy-benzyl, 3-trifluoromethoxy-benzyl, 4-trifluoromethoxy-benzyl, 3-chloro-4-fluoro-benzyl, 3-trifluoromethyl-4-fluoro-benzyl, 3-fluoro-4-trifluoromethyl-benzyl, 2-fluoro-5-trifluoromethyl-benzyl and 4-trilfuoromethyl-thio-benzyl; or pharmaceutically acceptable salt thereof.