Patent ID: 7919493

Claim:
A compound of formula (XVIIb): wherein R 1 and R 4 together form a group of formula (VIa) or (VIb): wherein the —CHNH 2 in formula (.VIa) is replaced by a group CHNH—CO—R a , or the —CHOH group in formula (VIb) is replaced by a group —CHO—CO—R a , wherein R a is: (i) aromatic heterocyclyl; or (ii) partially saturated heterocyclyl; or (iii) completely saturated heterocyclyl; and each of which is optionally substituted with one or more substituents selected from the group consisting of halo, cyano, nitro, carboxyalkyl, alkoxy, aryl, aryloxy, aromatic heterocyclyl, partially saturated heterocyclyl, completely saturated heterocyclyl, aromatic heterocyclyloxy, partially saturated heterocyclyloxy, completely saturated heterocyclyloxy, alkyl, haloalkyl, and amino; R 5 is H, —OH or O-acyl, wherein the acyl group is of formula —CO—R aa , wherein R aa is alkyl, alkoxy, alkenyl, arylalkyl, aryl, arylalkylene, amino acid, aromatic heterocyclyl, partially saturated heterocyclyl, or completely saturated heterocyclyl, each of which is optionally substituted with one or more substituents selected from the group consisting of halo, cyano, nitro, carboxyalkyl, alkoxy, haloalkoxy, aryl, aryloxy, heterocyclyl, heterocyclyloxy, alkyl, and amino; 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 14a and R 14b are both —H or one is —H and the other is —OH, —OCH 3 or —OCH 2 CH 3 , or R 14a and R 14b together form a keto group; R 15 is —H or —OH; R 21 is —H, —OH or —CN, wherein each of aryl and aryloxy, independently, contain 1 to 3 separate or fused rings and from 6 to 18 carbon ring atoms, and wherein each of heterocyclyl and heterocyclyloxy independently contain one, two or three heteroatoms selected from N, O or S atoms, and derivatives where the group —NCH 3 at the 12-position is replaced by —NH or —NCH 2 CH 3 ; or a pharmaceutically acceptable salt thereof.