Heterodiene synthesis

Both 1,4,-cycloaddition with the formation of a 1,4-dihydro-1,2,4-triazene derivative and electrophilic addition of acetyldicarboxylic acid ester to the secondary nitrogen atom occur during the reaction of acetylenedicarboxylic acid ester with 1,5-diphenyl-3-methyl-3-methylformazan. In the case of l,5.diphenylformazan, the reaction proceeds only in the second direction.See 3] for Communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1704–1705, December, 1970.