[Synthesis]
2,6-Dichloro-9-methyl-9H-purine (26) (1.01 g, 4.97 mmol) was used as a raw material and mixed with 32% ammonium hydroxide solution (20.4 mL, 164 mmol) in acetonitrile (20 mL). The reaction mixture was stirred at 55 °C for 5.5 hours. Subsequently, 32% ammonium hydroxide solution (20.4 mL, 164 mmol) was added to the reaction system and stirring was continued at 55°C for 19.5 hours. After completion of the reaction, the mixture was evaporated to dryness. The crude product obtained was suspended in methanol and filtered to afford the target compound 2-chloro-9-methyl-9H-purin-6-amine (27) as a white solid (746 mg, 82% yield) with a melting point >300 °C. The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3) δ 8.10 (s, 1H), 7.72 (s, 2H), 3.69 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 156.6 (C), 152.8 (C), 150.8 (C), 141.9 (CH), 117.6 (C), 29.5 ( CH3) confirmed. The mass spectrum (ESI, 20 V) showed a m/z of 184.1 (MH+, 100). |