THE IN-VITRO METABOLIC-ACTIVATION OF THE 11-TRIFLUOROMETHYL ANALOG OFTHE POTENT CARCINOGEN DIHYDRO-11-METHYL-CYCLOPENTA[A]-PHENANTHREN-17-ONE TO MUTAGENS

A strongly electronegative, bay-region analogue of the potent carcinog en -dihydro-11-methylcyclopenta[a]phenanthren-17-one, namely 11-triflu oromethylcyclopenta[a]phenanthren-17-one, is mutagenic to Salmonella t yphimurium TA100. Also it is metabolized at the 1,2- and 3,4-positions in the A-ring as well as C-15 in the D-ring to give rahydro-11-triflu oromethyl-cyclopenta[a]phenanthre n-17-one as the only mutagenic metab olite. In these respects its behaviour is closely similar to that of t he 11-methyl compound, suggesting that the electronic nature of the ba y-region substituent is rather less critical than its spatial configur ation in influencing metabolism to genotoxic intermediates. It remains to be seen, however, whether the trifluoromethyl compound is also a c arcinogen.