Substituted pyridines - Synthesis of 2-azafluorenone, 3-methyl-6, 7-benzoisoquinoline, and 7-methyl-2, 3-benzo-1, 6-naphthyridine

From γ-pyridones have been obtained substituted pyridine bases serving as the starting materials for the synthesis of polycyclic nitrogen-containing compounds. 2-Azafluorenone has been obtained by the cyclization of 4-phenylpyridine-3-carboxylic acid. The dehydrocyclization of 4-benzyl-2, 5-dimethylpyridine has given 3-methyl-6, 7-benzoisoquinoline and that of N-(2, 5-dimethyl-4-pyridyl)aniline has given 7-methyl-2, 3-benzo-1, 6-naphthyridine. © 1970 The Faraday Press, Inc.