Diaminomaleonitrile reacts with N-methylace-tonitrilium trifluoromethanesulphonate to give, after base treatment, the 5-amino-4-(cyanoformimidoyl) imidazole (4) which forms 6- cyanopurines with carboxylic acid anhydrides, and with aldehydes, ketones, 1, 2-and 1, 3- diketones, and keto-esters gives 6-carbamoyl-1, 2-dihydro-purine derivatives from which 6- carbamoylpurines can be obtained.
