Potentially carcinogenic cyclopenta[a]phenanthrenes. Part III. Oxidation studies

Abstract

Oxidation of 15,16-dihydroxyclopenta[a]phenanthren-17-one and of its strongly carcinogenic 11-methyl homologue with chromic acid, osmium tetroxide, lead tetra-acetate, and ammonium cerium(IV) nitrate was studied. The position of attack, either on the phenanthrene nucleus or on the five-membered ring D, depended mainly upon the oxidising agent and only to a minor extent upon the substrate. Both the biologically inactive hydrocarbon, 16,17-dihydro-15H-cyclopenta[a]phenanthrene, and its weakly carcinogenic 11-methyl homologue gave the corresponding 15-ketones as the main products on chromic acid oxidation.