3-Substituted pyridines. preparation of 3, 5-dimethylpyridine4-phenyldipyridine, and syntheses based on it

3, 5-Dimethyl-4-phenylpyridine is prepared by catalytic dehydrogenation and N-demethylation of 1, 3, 5-trimethyl-4-phenyl-Δ3-piperidine. Oxidation of the former gives 4-phenylpyridine-3, 5-dicarboxylic acid and the dimethyl ester and bis(diethylamide) of the acid are prepared. The same acid is used to prepare 4-phenylpyridine, methyl 2-azafluorenone-4-carboxylate, and also a compound assumed to be 6,14 dioxo3-azatetracyclo[9. 2. 1. 05, 13. O7,12]tetradeca-2, 4, 7, 9, 11, 13-hexaene. © 1969 The Faraday Press, Inc.