Patent ID: 8173821

Claim:
The compound of the formula: or a pharmaceutically acceptable salt thereof, wherein R 1 is selected from the group consisting of n-propyl, isobutyl, (C 3 -C 4 )cycloalkyl, and (C 3 -C 4 )cycloalkyl-methyl-; n is 1 or 2; and each R 2 is independently selected from the group consisting of fluoro, chloro, bromo, methyl, ethyl, trifluoromethyl, methoxy, ethoxy, cyclopropylmethyloxy, trifluoromethoxy, methylamino, cyclopropylamino and t-butylcarbonylamino, provided that when n is 2, at least one of R 2 is fluoro, chloro, bromo, methyl, ethyl, trifluoromethyl, methoxy, or ethoxy.