Synthesis of 3-azafluorene and 2h-2-methylindeno[1,2-c]pyridine

4-Methyl-3-phenylpyridine was isolated from the mixture of four isomeric methylphenyl-pyridines formed in the condensation of crotonaldehyde with phenylacetaldehyde (β-phenylethanol or phenylacetylene) with ammonia in the presence of a cadmium-calcium phosphate catalyst. 4-Methyl-3-phenylpyridine was converted to 3-azafluorene by catalytic dehydrocyclization. A representative of a new series of pseudoazulenes, viz., 2H-2-methylindeno[1,2-c]-pyridine, was obtained by treatment of 3-azafluorene methiodide with sodium hydroxide solution; the product was a crystalline black substance that remained unchanged during storage in air for 1 month. © 1981 Plenum Publishing Corporation.