The conversion of l,3-dimethyl-2,6-diphenyl-4-benzyl-4-piperidol and its N-unsubstituted analog by means of pyridine N-oxide to 3-methyl-2,6-diphenyl-4-benzylpyridine (I) is accompanied by the formation of l,2-diphenyl-l,2-bis(3'-methyl-2',6'-diphenyl-4'-pyridyl)ethane, which was obtained under the same conditions directly from y-benzyl-substituted pyridine I. The initial product in the catalytic dehydrocyclization of pyridine base I is l,3-diphenylbenzo[g]isoquinoline, which is subsequently partially converted to 7-phenyl-8-azabenzo[a]fluoranthene. Spectral data for these heterocyclic compounds and the characteristics of the substances obtained by oxidation of them are presented. © 1979 Plenum Publishing Corporation.