Patent ID: 7915242

Claim:
A compound of formula I, a tautomer of the compound, a pharmaceutically acceptable salt of the compound, or a pharmaceutically acceptable salt of the tautomer wherein X is an R 1 group or is a group of formula —OR 1 wherein R 1 is a straight or branched chain alkyl group having 1 to 8 carbon atoms; R 2 and R 3 are independently selected from H or straight or branched chain alkyl groups having 1 to 4 carbon atoms; or R 2 and R 3 join together to form a ring having 3 to 6 ring members; R 4 is a straight or branched chain alkyl group having 1 to 6 carbon atoms; R 5 is H; or R 4 and R 5 together represent a ═CH 2 group; and R 6 is OH and R 7 is H; R 6 is an O-alkyl group and R 7 is H, wherein the alkyl group of the O-alkyl group is a straight or branched chain alkyl group having from 1 to 8 carbon atoms; or R 6 and R 7 together represent a ═O group.