Heterocycles

Cyclization of 2-dicyanomethylene-1, 2-dihydropyridine-3-carbonitriles with hydrogen halides: a re-examination of the regioselectivity

P Victory, N Busquets, JI Borrell, J Teixidó, B Serra…

Index: Victory, Pedro; Busquets, Nuria; Borrell, Jose I.; Teixido, Jordi; Serra, Blanca; et al. Heterocycles, 1995 , vol. 41, # 5 p. 1013 - 1022

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Citation Number: 12

Abstract

The cyclization of the title compounds (5a-c) with HCl and HBr has been re-examined. In all cases 5-amino-7-halo-substituted 1, 6-naphthyridines (11a-c and 12a-c) were formed independently of the thermal level and the hydrogen halide employed. The structures of 11a- c and 12a-c were unequivocally established by reaction with hydrazine which afforded the corresponding pyrazolo [3, 4-h][1, 6] naphthyridines (14a-c). The structure of the methoxy ...