反应详情

温度

85 °C

4-Bromo-2-fluorobenzamide (9.53 g, 43.7 mmol) and N,N-dimethylformamide dimethylacetal (75.0 mL) were combined in a 500 mL round bottom flask and purged with nitrogen. The reaction was heated to reflux at 85° C. for 2 h. The resulting mixture was concentrated under reduced pressure and dried under vacuum to afford a yellow oil. The oil was suspended in concentrated acetic acid (75.0 mL) and cooled to 0° C. Hydrazine hydrate (21.88 g, 437 mmol) was added dropwise and the mixture was allowed to stir at rt for 5 h. The reaction was poured warm onto cold ice and extracted with dichloromethane (3×200 mL). Organic volatiles were removed under reduced pressure to afford 3-(4-bromo-2-fluorophenyl)-4H-1,2,4-triazole (7.20 g, 29.7 mmol, 68.1% yield) as a white solid. MS (ESI) m/z 241.9 [M]+, 243.9 [M+2]+.

1. custompurged with nitrogen
2. temperatureThe reaction was heated
3. concentrationThe resulting mixture was concentrated under reduced pressure
4. customdried under vacuum
5. customto afford a yellow oil
6. temperaturecooled to 0° C
7. additionThe reaction was poured
8. temperaturewarm onto cold ice
9. extractionextracted with dichloromethane (3×200 mL)
10. customOrganic volatiles were removed under reduced pressure