SYNTHESIS AND MUTAGENICITY OF SOME CYCLOPENTA[C]PHENANTHRENES AND INDENO[C]PHENANTHRENES

An efficient two-step synthesis of ,12-tetra-hydrodicyclopenta[a,c]phe nanthren-7-one, based on the high pressure Diels-Alder cycloaddition o f 4-acetoxy-2-cyclopenten-1-one with 1-(1-naphthyl)cyclopentene and a subsequent dehydrogenation-aromatization reaction, is reported. Furthe r, the synthesis of two cyclopenta[c]phenanthrenes and indeno[c]phenan threnes is described. Structural analysis of the new products by H-1 a nd C-13 NMR spectroscopy is presented, The mutagenic activity of the c ompounds in Salmonella typhimurium was estimated by Ames' test. Three compounds were shown to be mutagenic for the strain TA 100. The mutage nic activities exhibited by cyclopenta[c]phenanthrenes are compared wi th those shown by the related cyclopenta[a]phenanthrenes and then disc ussed with respect to the effect of the cyclopentane ring facing the b ay region. Indeno[c]phenanthrenes are mostly inactive. The effect of b enzoannulation on the mutagenic activities of cyclopenta[c]phenanthren es is discussed.