Solvent-free Synthesis of 5-Azacytosine with Microwave Activation

摘要

5-Azacytosine (4-amino-1,2-dihydro-1,3,5-triazin-2-one) is a very important intermediate in the synthesis of 5-azacytidine which showed remarkable bacteriostatic and cytostatic activity as well as against T-4 lymphoma and L-1210 leukemia in mice. Starting with N-cyanoguanidine (dicyandiamide) and formic acid, under the solvent-free microwave activation,we synthesized 5-azacytosine in short time (4min) with good yield (60.4%). The structure of the product was confirmed by 1HNMR and Elemental analysis.In this paper, a new and rapid synthesis of 5-azacytosine has been reported for the first time in microwave oven. N-cyanoguanidine (0.05tmol) and anhydride formic acid (0.18mol) were stirred well. Then irradiate the reaction mixture in microwave oven for the specified time (4min) under solvent-free condition. After the reaction was complete, the resulting solid was disperated in warm absolute ethanol (10ml), cooled to 0℃, filtered and dried in vacuum to yield the crude product. The pure product was obtained by recrystallization.