反应详情

N-Acetylphenylhydroxylamine (100 g) and 2-chloropyrazine (79 g) were dissolved in anhydrous dimethylformamide (500 ml). Sodium hydride (50% oil; 46 g) was added in portions over 11/2 hours, ensuring that the temperature was maintained between 20°-40° C. The reaction mixture was cooled, diluted with water (2500 ml), washed with dichloromethane (4 times) and filtered through diatomaceous earth. Acetic acid was slowly added with stirring to take the pH of the filtrate to 5-6. During this addition crystalline solid formed. After 30 minutes, this was collected by filtration, washed with very dilute acetic acid and dried at 60° C. to yield 5-(4-acetamidophenyl)-2-(1H)-pyrazinone (94.6 g).

1. temperaturewas maintained between 20°-40° C
2. temperatureThe reaction mixture was cooled
3. washwashed with dichloromethane (4 times)
4. filtrationfiltered through diatomaceous earth
5. additionAcetic acid was slowly added
6. customDuring this addition crystalline solid formed
7. filtrationthis was collected by filtration
8. washwashed with very dilute acetic acid
9. customdried at 60° C.