(Z)-N3-(2-amino-1,2-dicyanovinyl)formamidrazone: a precursor in the synthesis of 1,5-diaminoimidazoles and 6-carbamoyl-1,2-dihydropurines
Abstract
The reaction of ethyl (Z)-N-(2-amino-1,2-dicyanovinyl)formimidate with hydrazine monohydrate leads to (Z)-N3-(2-amino-1,2-dicyanovinyl)formamidrazone in almost quantitative yield. This compound proved to be an important starting material for the synthesis of the corresponding N1-isopropylidene-and N1-acetyl-formamidrazones.
The amidrazones prepared promptly cyclize in the presence of base to give a 1,5-diamino-4-cyanoimidazole or a 1,5-diamino-4-(cyanoformimidoyl)imidazole, depending on the reaction conditions and mainly on the nature of the base used to induce cyclization.
1,5-Diamino-4-(cyanoformimidoyl)imidazole was treated with carbonyl compounds and the 1,2-dihydropurines thus isolated indicated that the amino group in position 5 is more reactive than that in position 1.