| abstract |
Compounds of the formula (I) wherein: R1, R2, R3 are independently selected from the group consisting of hydrogen atoms, optionally substituted alkanoyl groups and alkenylcarbonyl groups, provided that at least one of R1, R2 and R3 represents a group unsubstituted alkanoyl having 5 to 24 carbon atoms, said substituted alkanoyl group or said alkenylcarbonyl group; and one of R4 and R5 represents a hydrogen atom and the other represents a cyano group; They have antitumor activity. |