The general procedure for the synthesis of N-(6-hydroxy-9H-purin-2-yl)acetamide from guanine is as follows:Example 52 Preparation of N2-acetyl guanine. Guanine (10.1 g) was suspended in N,N-dimethylacetamide (100 ml) followed by the addition of acetic anhydride (20 ml). The reaction mixture was stirred under reflux conditions for 2 h followed by thermal filtration. The filtrate was cooled to room temperature and the precipitated solid was filtered. The solid was suspended in ethanol (66 ml) and stirred for 1.5 hours and then filtered. The resulting solid was placed in 50% ethanol and stirred at reflux for 3 hours, followed by cooling of the solution. The solid product was obtained by filtration, washed with 50% ethanol and dried to give the target compound N2-acetylguanine (9.36 g, 72.7% yield) as a white solid.1H NMR (DMSO-d6) δ 13.14 (broad peak, 1H), 12.14 (broad peak, 1H), 11.67 (broad peak, 1H), 8.10 (broad peak, 1H), 2.28 ( single peak, 3H).
