Patent ID: 7423067

Claim:
A compound of structural formula I: or a pharmaceutically acceptable salt thereof, wherein: R 1 is phenyl, wherein phenyl is substituted with one, two, three or four substituents independently selected from R b ; R 2 is phenyl, wherein phenyl is optionally substituted with one, two, three or four substituents independently selected from R b ; R 3 is methyl; R 4 is selected from: (1) hydrogen, (2) methyl, (3) —OH, (4) —O-phenyl, (5) —NH 2 , (6) —NH-phenyl, (7) —NH(CO)O-alkyl, (8) phenyl, and (9) pyridyl, wherein methyl and alkyl are optionally substituted with one, two, three or four substituents independently selected from R a , and phenyl and pyridyl are optionally substituted with one, two, three or four substituents independently selected from R b ; R 6 is hydrogen; A is each R a is independently selected from: (1) —OR c , (2) halogen, (3) —S(O) m R c , (4) —SR c , (5) —C(O)R c , (6) —CO 2 R i , (7) —CN, (8) CF 3 , and (9) oxo; each R b is independently selected from: (1) R a , (2) methyl, (3) ethyl, (4) propyl, (5) phenyl, (6) benzyl, and (7) pyridyl; each R c is independently selected from: (1) C 1-10 alkyl, and (2) phenyl R i is (1) C 1-10 alkyl; and m is 2.