Synthesis of 4-substituted 8-amino-4,5-dihydro-3H-pyrrolo[3,4-f]-1,3,5-triazepin-6-ones and 5-amino-2-aryl-4-(1-aryl-5-alkylideneaminoimidazol-4-yl)1,3-oxazoles

Abstract

The title compounds have been prepared from (Z)-N²-(2-amino-1, 2-dicyanovinyl)formimidamide by reaction of an excess of an aldehyde or ketone in the presence of a base. The triazepine 1e can also be obtained by the reaction of ethyl (Z)-N-(2-carbamoyl-1-cyano-2-isopropylideneaminovinyl)formimidate 7a with ammonia and a catalytic amount of anilinium hydrochloride. Under similar conditions the 2-benzylideneamino derivative 7b affords the corresponding amidine 6, and only a low yield of the triazepine. In this last reaction aminolysis of the alkylideneamino bond competes with amidine formation to give compound 8, and reaction between the formimidate 7c and p- anisidine resulted only in the formation of ethyl (Z)-N-(2-amino-2-carbamoyl-1-cyanovinyl)formimidate 8. Reactions between N²-aryl-(Z)-N¹-(2-amino-1,2-dicyanovinyl)formimidamides and aldehydes in the presence of a base do not give 1, 3, 5-triazepines, but instead afford novel 5-amino-2-aryl-4-(1aryl-5-alkylideneaminoimidazol-4-yl)-1, 3-oxazoles 11 together with the known 9-aryl-6carbamoyl-1, 2-dihydropurines, the corresponding purines and other products.