| abstract |
A compound of formula I: ** Formula ** or a pharmaceutically acceptable salt thereof, wherein R 1 is 1-phenyl-1-oxo- (C 2 -C 6 alkyl) optionally substituted at the 4-position of the phenyl with halo, R 2 is cyclohexyl ; ** Formula ** R3 is ** Formula ** and R10 is H or alkyl of one to six carbons. |