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Derivatives of azaindoles. 65. Synthesis of 1-benzyl-4-methyl-5-cyano-6-hydroxy-7-azaindoline

Research paper by T. V. Sycheva, E. F. Kuleshova, L. N. Yakhontov

Indexed on: 01 Aug '84Published on: 01 Aug '84Published in: Chemistry of Heterocyclic Compounds



Abstract

Treatment of the ammonium (I) or benzylammonium salt of 2,6-dihydroxy-3-(β-hydroxyethyl)-4-methyl-5-cyanopyridine (II) with a mixture of benzylamine and phosphorus pentoxide yielded 2-benzylamino-3-(β-hydroxyethyl)-4-methyl-5-cyano-6-hydroxypyri-dine (III), which, when heated with phosphorus oxychloride, is converted to 1-benzyl-4-methyl-5-cyano-6-hydroxy-7-azaindoline (IV). The products of thermal fragmentation of II with benzylamine were studied by the method of chromato-mass spectrometry. In addition to compound III, N,N′-dibenzylurea (V) and the dibenzylamide of malonic acid (VI) were preparatively isolated from the reaction products. The cyclization of I and II to 4-methyl-6-hydroxy-2,3-dihydro-7-azabenzofuran (VII) and 4-methyl-5-cyano-6-hydroxy-2,3-dihydro-7-azabenzofuran (VIII) was carried out. Heating VIII with benzylamine at 200–210°C led to compound III.