반응 #748221

반응 방정식

hydrazine

4-bromo-2-fluorobenzaldehyde

→

6-bromo-1H-indazole

수율 78.3%

반응 조건

후처리

1. 1
   온도After cooling to ambient temperature
2. 2
   농축the solution was concentrated under reduced pressure
3. 3
   기타The solution was quenched
4. 4
   workup.ADDITIONby pouring it
5. 5
   workup.ADDITIONinto a mixture of ice water (100 mL)
6. 6
   추출extracting with EtOAc (3×100 mL)
7. 7
   건조dried over sodium sulfate
8. 8
   여과filtered
9. 9
   기타The solution was evaporated to dryness
10. 10
    기타The crude product was purified
11. 11
    세척eluting with a gradient of 0% to 100% EtOAc in hexanes

실험 절차

To a 100 mL round-bottomed flask was added hydrazine (30 mL, 832 mmol) and 4-bromo-2-fluorobenzaldehyde (4.69 g, 23 mmol). The solution was stirred at 125° C. for 3 hours. After cooling to ambient temperature, the solution was concentrated under reduced pressure. The solution was quenched by pouring it into a mixture of ice water (100 mL), and then extracting with EtOAc (3×100 mL). The organic layers were combined, dried over sodium sulfate, and filtered. The solution was evaporated to dryness, and adsorbed onto silica gel. The crude product was purified using column chromatography through a Redi-Sep® pre-packed silica gel column (40 g), eluting with a gradient of 0% to 100% EtOAc in hexanes, to provide 6-bromo-1H-indazole (4.6 g, 18 mmol, 76% yield). LCMS (M+H) 197.9 calc. for C7H5BrN2 197.0, 1H NMR (400 MHz, CD3OD): δ ppm 8.03 (s, 1H), 7.67-7.72 (2H, m), 7.24-7.26 (m, 1H).

출처