Reaction of several hydrazinobenzoquinolines with 1,3-diketones affords pyrazolylbenzoquinolines rather than the reported benzodiazepinoquinolines. The structural assignment is based upon NMR (1H and 13C) spectral data and an unambiguous synthesis.
Cyclization of 2-hydrazino-4-methylbenzo[h]quinoline and 3-hydrazino-1-methylbenzo[f]quinoline with formic acid occurs on nitrogen rather than carbon to give 5-methylbenzo[h][1,2,4]triazolo[4,3-a]quinoline and 11-methylbenzo[f][1,2,4]triazolo[4,3-a]quinoline and not 7-methyl-10H-benzo[h]pyrazolo[3,4-b]quinoline and 11-methyl-8H-benzo[f]pyrazolo[3,4-b]quinoline, respectively, as it has been claimed before