| abstract |
Compounds of formula (I) in which: R1 represents a hydrogen atom or an O-protecting group; R2 represents a hydroxyl, lower alkoxy, carboxaldehyde, lower alk-1-enyl or hydroxy- or lower alkoxy-substituted lower alkyl group; R3 represents a methyl group having α- or β- configuration; X represents a C¿1-3? alkylene group or a valence bond; Y represents a carboxaldehyde group or a group of formula -C(R?4) (R5)OR1¿ where R1 is as defined above and R?4 and R5¿, which may be the same or different, are each selected from hydrogen atoms, alkyl, alkenyl and alkynyl groups such that the total carbon content of R?4 and R5¿ does not exceed three atoms, with the proviso that X is a valence bond when both R?4 and R5¿ are other than hydrogen; and the dotted line signifies that a double bond may optionally be present at the 16(17) -position exhibit potent cell modulating activity, including antiproliferative and antiangiogenic effects. |