Selective hydrogenation and dehydrocyclization of 3-methyl-4-benzyl-2,6-diphenylpyridine

3-Methyl-4-benzyl-2,6-diphenylpiperidine was obtained by hydrogenation of 3-methyl-4-benzyl-2,6-diphenylpyridine in the presence of rhenium heptasulfide; this confirms the common character of the method of selective hydrogenation of aryl(aralkyl)-substituted pyridine bases to give similarly substituted piperidines. Dehydrocyclization of this pyridine base by heating with sulfur leads to 10-mercapto-1,3-diphenyl-2-azaanthracene, which was obtained under the same conditions from 1,2-diphenyl-1,2-bis(3-methyl-2,6-diphenyl-4-pyridyl)ethane. © 1982 Plenum Publishing Corporation.