The syntheses of 4b,5a‐dihydro‐5 H ‐benzo[3,4]‐phenanthro[1,2‐ b ]azirine and 1a,11b‐dihydro‐6,11‐dimethyl‐1 H ‐benz[3,4]anthra[1,2‐ b ]azirine

The syntheses of the K‐imine derivatives of carcinogenic benzo[ c ]phenanthrene and 7,12‐dimethylbenz‐[ a ]anthracene are described. Treatment of trans ‐5‐azido‐5,6‐dihydrobenzo[ c ]phenanthren‐6‐ol ( 3 ) and trans ‐6‐azido‐5,6‐dihydrobenzo[ c ]phenanthren‐5‐ol ( 5 ) with thionyl chloride yielded the corresponding β‐chloro azides, which in turn, were reacted with lithium aluminium hydride to give 4b,5a‐dihydro‐5 H ‐benzo[3,4]‐phenanthro[1,2‐ b ]azirine ( 2 ). In a similar manner trans ‐5‐azido‐5,6‐dihydro‐7,12‐dimethylbenz[ a ]anthracen‐6‐ol ( 11 ) and trans ‐6‐azido‐5,6‐dihydro‐7,12‐dimethylbenz[ a ]anthracen‐5‐ol ( 13 ) were transformed to the respective chloro azides and, converted into 1a,11b‐dihydro‐6,11‐dimethyl‐1 H ‐benz[3,4]anthra[1,2‐ b ]azirine ( 10 ).