Synthesis and mutagenicity of some cyclopenta[c]phenanthrenes and indeno[c]phenanthrenes

An efficient two-step synthesis of 8(H)-9,10,11,12-tetrahydrodicyclopenta[a,c]phenanthren-7-one,based on the high pressure Diels-Alder cycloaddition of 4-acetoxy-2-cyclopenten-1-onewith1-(1-naphthyl)cyclopentene and a subsequent dehydrogenation-aromatizationreaction, is reported. Further, the synthesis of two cyclopenta[c]-phenanthrenesand indeno[c] phenanthrenes is described. Structural analysisof the new products by ¹H and ¹³C NMR spectroscopy is presented.The mutagenic activity of the compounds in Salmonella typhimuriumwas estimated by Ames' test. Three compounds were shown to bemutagenic for the strain TA 100. The mutagenic activities exhibitedby cyclopenta[c]phenanthrenes are compared with those shownby the related cyclopenta[a]phenanthrenes and then discussedwith respect to the effect of the cyclopentane ring facing thebay region. Indeno[c]phenanthrenes are mostly inactive. Theeffect of benzoannulation on the mutagenic activities of cyclopenta[c]phenanthrenesis discussed.