REACTIONS OF 9-ARYL-6-CYANOPURINES WITH PRIMARY AMINES

摘要

Two structural isomers (9-aryl-6-cyanopurines and imidazole-4,5-dicarbonitriles) were isolated from the reaction of (Z)-N1-aryl-N2-(2-amino-1,2-dicyanovinyl)formamidines with triethyl orthoacetate or propionate. On the other hand, 9-aryl-6-cyanopurines were the only product, when triethyl orthoformate was used. The reaction of 9-aryl-6-cyanopurines with hydroxylamine hydrochloride in dichloromethane/ethanol at room temperature furnished 6-amidinopurines, while reaction with primary amines afforded pyrimido[5,4-d]pyrimidines. In addition, 9-aryl-6-cyanopurines reacted with hydrazine monohydrate under mild conditions to give 4-imino-N~8-arylpyrimido[5,4-d]pyrimidines. The latter furnished novel pyrimido[4,5-e][1,2,4]triazolo[1,5-c]pyrimidines when refluxed with an excess of triethyl orthoesters. The new compounds were fully characterized and single crystal X-ray analyses have been carried out on 9-(4-methoxyphenyl)-9H-purine-6-carboximidamide and 2-methyl-1-[(E)-p-tolyliminomethyl] -1H-imidazole-4,5 -dicarbonitrile.