Patent ID: 7470723

Claim:
A compound of the formula: or a pharmaceutically acceptable salt thereof, wherein: one of R 1 and R 2 is —CN, and the other is —H, substituted or unsubstituted lower alkyl, substituted or unsubstituted alkenyl, or substituted or unsubstituted alkynyl; each occurrence of R c and R d is independently —H, substituted or unsubstituted lower alkyl, or substituted or unsubstituted alkoxy; R 3 is substituted or unsubstituted C 2-8 alkyl, or substituted or unsubstituted alkoxy; R 4 is substituted or unsubstituted C 2-8 alkyl, or substituted or unsubstituted alkoxy; R 5 is substituted or unsubstituted C 2-8 alkyl, or substituted or unsubstituted alkoxy; R 6 is —H, substituted or unsubstituted lower alkyl, or substituted or unsubstituted alkoxy; each occurrence of R 16 and R 17 is independently —H or halogen, and wherein R 8 with R 7 , together form —O—C(R 16 R 17 )—O—.