Treatment of 5-(amino)imidazole-4-carbonitrile 1 with a mixture of acetic anhydride and acetic acid afforded, the unexpected 5-(acetylamino)imidazole-4-(N-acetyl)carboxamide 2, but upon reacting 1 with acetic anhydride for a short time, the 5-(diacetylamino)imidazole-4-carbonitrile 4 was obtained. Reaction of 2 and 4 with hydrazine hydrate gave the condensation products 6 and 8a respectively. Upon reacting 2 with methylamine and hydroxylamine, the 5-(amino)imidazole derivative 7 was afforded, but reaction of 4 with the same reagents gave products 8b and 11 respectively. Cyclization of 2 and 4 in alkaline medium was carried out to afford the 2-methylpurin-6(1H)-one derivative 13. Treatment of the latter product with phosphoryl chloride, followed by reaction with some cyclic 2T amines and amino acids gave the 6-substituted purines 15-17. Moreover, when 1 was allowed to react with alkyl isocyanate the urea derivatives 19 were afforded. Also, the 8-substituted purines 20 and were obtained from 19.