Patent ID: 7741323

Claim:
A compound of formula (I) or a pharmaceutically acceptable salt thereof: wherein, R 1 is C 1-6 alkyl, C 1-6 alkenyl, or C 3-6 cycloalkyl, each of which is unsubstituted or substituted with one or more phenyl groups; R 2 is H, CN, CO 2 R a , CH 2 CO 2 R a , CONR b R c , or phenyl; R 3 is C 1-6 alkyl, C 3-6 cycloalkyl, naphthyl, phenyl, being each unsubstituted or substituted with one or more substituents selected from the group consisting of halogen, CN, NH 2 , NO 2 , OR a , phenyloxy, C 1-6 alkyl, and C 3-6 cycloalkyl; and R 4 , R 5 , R 6 , and R 7 are each independently H, OH, OSO 2 CH 3 , O(CH 2 ) m R e , CH 2 R f , OCOCH 2 OR g , OCH 2 CH 2 OR g , OCH 2 CH═CHR g , or R 5 and R 6 together form OCH 2 O; in which R a is H, C 1-6 alkyl, or C 3-6 cycloalkyl, C 1-6 alkyl and C 3-6 cycloalkyl being each unsubstituted or substituted with one or more halogens; R b and R c are each independently H, C 1-6 alkyl, or C 3-6 cycloalkyl; R d is O, S, or NR a ; R e is H, halogen, C 3-6 cycloalkyl, naphthyl, or phenyl, phenyl being unsubstituted or substituted with one or more substituents selected from the group consisting of halogen, CN, NH 2 , NO 2 , OR a , CF 3 , and COOR a ; R f is OCH 2 CH 2 R g or R g is phenyl, which is unsubstituted or substituted with one or more substituents selected from the group consisting of halogen, CN, NH 2 , NO 2 , and OR a ; and m is an integer in the range of 1 to 5.