Abstract: A compound selected from the group consisting of compounds of the formula ##STR1## wherein R.sub.1 is an organo of 1 to 18 carbon atoms optionally containing at least one heteroatom connected to the C ring by a carbon atom, R.sub.2 is methyl or ethyl, the A and B rings being selected from the group consisting of ##STR2## Re is selected from the group consisting of hydrogen, optionally substituted alkyl of 1 to 6 carbon atoms and acyl and the D ring is selected from the group consisting of ##STR3## one of R.sub.3 and R.sub.4 is selected from the group consisting of hydroxy, protected hydroxy, acyl and alkoxy and the other is an optionally substituted aryl, R.sub.5 is an optionally substituted aryl and their non-toxic, pharmaceutically acceptable salts with acids and bases with the proviso that when the A and B rings are ##STR4## R.sub.1 is ##STR5## R.sub.2 is methyl, R.sub.3 is --OH, R.sub.4 is phenyl having anti proliferative properties.