Reaction of pyrylium salts with hydrazine and methylhydrazine. Concerning the scope of the 1, 2 (4 H)-diazepine synthesis

DJ Harris, GYP Kan, T Tschamber…

Index: Harris, D. J.; Kan, G. Y.-P.; Tschamber, T.; Snieckus, V. Canadian Journal of Chemistry, 1980 , vol. 58, p. 494 - 500

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Citation Number: 6

Abstract

The reaction of pyrylium salts 1 ae with methylhydrazine gives pyrazolines (2), pyrazoles (3), pyridines (4), 1, 2-diazepine (5), and N-methylaminopyridinium salts (6). Product composition has been studied as a function of pyrylium salt counter anion, concentration of methylhydrazine, and conditions of the reaction (Table 1). Pyridines (4) and 1, 2-diazepines (5) are minor components, the major products being the pyrazolines (2) and pyrazoles (3). ...