An effective procedure for the preparation of 3-substituted-4- or 6-azaindoles from ortho-methyl nitro pyridines

3-Substituted-4- and 6-azaindoles were prepared from ortho-methyl-nitropyridines in a practically convenient, one-pot process based on the Leimgruber–Batcho reaction. The procedure comprises a sequence of (a) condensation of an ortho-methyl-nitropyridine with N,N-dimethylformamide dimethyl acetal; (b) alkylation or acylation of the enamine intermediate; (c) reduction of the nitro group to an aniline with in situ cyclization and elimination of dimethylamine to generate the 3-substituted azaindole heterocycle.