In one of the earlier papers of this Series, we have reported1 the synthesis of 5-substituted derivatives of 6-azacytosine (5-amino-2, 3-dihydro-1, 2, 4-triazin-3-one)(I). This synthesis starts from nitriles of a-keto acids which are converted to semicarbazones and the latter cyclised to 5-alkyland 5-aryl-6-azacytosines. This procedure could be suitable also for the preparation of 6-azacytosine itself since the known2-4 syntheses of this compound are ...
