反应详情

Bromoacetaldehyde dimethyl acetal (2.57 g, 13.1 mmol), 48% hydrobromic acid (1.06 g, 13.1 mmol) and water (1.5 ml) were heated at 95° C. for 1.5 h. The mixture was allowed to cool to ambient temperature, diluted with propan-2-ol (20 ml) then treated with sodium hydrogen-carbonate (1.46 g, 17.4 mmol) added in portions over 5 min. The mixture was filtered and the filtrate was added to 6-amino-4-methyl-3-methylsulfanyl-4H-[1,2,4]triazin-5-one (1.50 g, 8.71 mmol). The resulting suspension was heated at 95° C. for 18 h. The mixture was allowed to cool to ambient temperature, diluted with methanol (100 ml) and evaporated onto silica. The product was purified by flash column chromatography on silica eluting with dichloromethane (+0.1% 0.880 ammonia) on a gradient of methanol (3-6%). Collecting appropriate fractions gave 3-methyl-2-methylsulfanyl-3H-imidazo[2,1-f][1,2,4]triazin-4-one (0.81 g, 47%) as a pale yellow solid: δH (400 MHz, CDCl3) 2.61 (3H, s), 3.58 (3H, s), 7.49 (1H, d, J1), 7.52 (1H, d, J1).

1. additionadded in portions over 5 min
2. filtrationThe mixture was filtered
3. temperatureThe resulting suspension was heated at 95° C. for 18 h
4. temperatureto cool to ambient temperature
5. customevaporated onto silica
6. customThe product was purified by flash column chromatography on silica eluting with dichloromethane (+0.1% 0.880 ammonia) on a gradient of methanol (3-6%)
7. customCollecting appropriate fractions