Patent ID: 7767659

Claim:
A compound of the formula (Ab): wherein R a and R b together with the carbon to which they are attached form a group: —C(═O)—; —CHOX 1 or —CHNX 1 X 2 where each X 1 and X 2 is independently selected from hydrogen, substituted or unsubstituted C 1 -C 18 alkyl, substituted or unsubstituted C 2 -C 18 alkenyl, substituted or unsubstituted C 2 -C 18 alkynyl, substituted or unsubstituted aryl, protecting group, and —C(═O)R′ wherein R′ is selected from hydrogen, OH, NO 2 , NH 2 , SH, CN, halogen, C 1 -C 6 alkyl, alkenyl, alkynyl, aryl, aralkyl and heterocyclic; or a group of formula: wherein R d and X 1 are independently selected from hydrogen, substituted or unsubstituted R′, OR′, —C(═O)R′, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, and substituted or unsubstituted aralkyl, wherein R′ is selected from hydrogen, OH, NO 2 , NH 2 , SH, CN, halogen, C(═O)H, C(═O)CH 3 , CO 2 H, CO 2 CH 3 , C 1 -C 6 alkyl, alkenyl, alkynyl, aryl, aralkyl and heterocyclic; X is —O— or —NH—; R 5 is OX 1 wherein X 1 is hydrogen, substituted or unsubstituted C 1 -C 18 alkyl, substituted or unsubstituted C 2 -C 18 alkenyl, substituted or unsubstituted C 2 -C 18 alkynyl, substituted or unsubstituted aryl, or —C(═O)R′ wherein R′ is selected from of hydrogen, OH, NO 2 , NH 2 , SH, CN, halogen, C 1 -C 6 alkyl, alkenyl, alkynyl, aryl, aralkyl and heterocyclic; R 7 is —OCH 3 and R 8 is —OH, or R 7 and R 8 together form a group —O—CH 2 —O—; R 12b is hydrogen, substituted or unsubstituted alkyl, haloalkyl, alkoxyalkyl, haloalkoxyalkyl, arylalkylene, haloalkylarylalkylene, acyl, haloacyl, carbonate, carbamate, arylalkyl, alkenyl and amino acid; and R 21 is —H, —OH or —CN.