Acetyl chloride → 1-Ethyl-2-methyl-5,6-diphenyl-1H-imidazo[4,5-b]pyrazine

Participants

Reaction Conditions

Reaction Steps

2-Chloro-3-ethylamino-5,6-diphenylpyrazine, (3.10 g, 0.01 moles) is dissolved in benzene (50 ml) and then triethylamine (1.29 g, 0.013 moles) and acetyl chloride (1.00 g, 0.013 moles) are added. The solution is refluxed 41/2 hours, cooled to 15°C and filtered. The filtrate is diluted with ethanol (3ml), warmed briefly at 50°C and then all volatile materials evaporated. The resultant brown oil is treated with liquid ammonia (17 g) in ethanol (60 ml) in a bomb at 165°C for 12 hours. The solution is diluted with water (200 ml), cooled and the yellow precipitate filtered off. The solid is triturated with boiling 50% aqueous methanol, filtered, and the filtrate chilled. The product is collected by filtration. Yield 0.45 g (14%). It is recrystallized from benzene-heptane, m.p. 178.5°-180°C.

Provenance & Evidence