Photochemical transformations. Part XXIX. Steric compression effects in the synthesis and reactions of 4-amino-5-methylphenanthrene

Abstract

The nitrite ester of 4-hydroxy-4-methyl-1,2,3,4,5,6,7,8-octahydrophenanthrene was photolysed to give 4-hydroxy-5-hydroxyimino-4-methyl-1,2,3,4,5,6,7,8-octahydrophenanthrene. The Semmler aromatisation reaction of this and related compounds was investigated and applied to the formation of 4-amino-5-methylphenanthrene. Alternative routes commencing from pyrene always gave internal cyclisation products caused by steric compression between the phenanthrene substituents at position 4 and 5. A useful variant of a Lossen-type reaction of dicarboxylic acid oxime toluene-p-sulphonates is reported.