The general procedure for the synthesis of 8-methyl-7H-purin-6-amine from acetamide and 4,5,6-triamino-pyrimidine sulfate was as follows: step 1: 4,5,6-triamino-pyrimidine sulfate (3.0 g, 13.4 mmol) and acetamide (1.0 g, 16.9 mmol) were added to a 25 mL autoclave and the reaction was heated to 240°C for 6 hours. Upon completion of the reaction, the crude product was boiled in boiling water for 1 h and subsequently filtered through a diatomaceous earth pad. The filtrate was concentrated and purified by high performance liquid chromatography (HPLC) under the following conditions: gradient elution with 0-10% buffer B (buffer A: 0.1% aqueous solution of triethylammonium acetate; buffer B: acetonitrile solution of 0.1% triethylammonium acetate) for 30 min at a flow rate of 10 mL/min. The fraction corresponding to the target product was collected and concentrated in vacuum to afford 225 mg (11% yield ) of 8-methyl-7H-purin-6-amine.
