Heterogeneous-catalytic fischer reaction

The catalytic synthesis of 7-azaindole and its 2-methyl derivative has been accomplished for the first time by cyclization of acetaldehyde and acetone 2-pyridylhydrazones in the presence of γ-Al2O3 and fluorinated aluminum oxide. The temperature dependence of the yields of reaction products — azaindoles and 2-aminopyridine — was studied. The cyclization of acetaldehyde 2-pyridylhydrazone proceeds under more severe conditions. The maximum yield of 7-azaindole is 15% at 450° on fluorinated aluminum oxide. The yield of 2-methyl-7-azaindole reaches 50% at 315°. Fluorinated aluminum oxide displays higher catalytic activity.