29095-16-7Relevant articles and documents
Reaction of pyrylium salts with hydrazine and methylhydrazine. Concerning the scope of the 1,2(4H)-diazepine synthesis
Harris, D. J.,Kan, G. Y.-P.,Tschamber, T.,Snieckus, V.
, p. 494 - 500 (2007/10/02)
The reaction of pyrylium salts 1a-e 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).The reactions of more unusual pyrylium salts(1f-i, 8a, 9a, 9c, and 11a) with hydrazine have been shown to provide 1,2(4H)-diazepines(10, 12-15) and N-aminopyridinium salts(8b, 9b) (Table 2), the nature of the product apparently depending on the absence or presence of 2-methyl substitution respectively in the starting pyrylium salts.
