Hydrazine hydrate (1:1) → 5-Bromo-7-fluoro-1H-indazole

Temperature

90 °C

A mixture of (E)-5-bromo-2,3-difluorobenzaldehyde O-methyl oxime (19.65 g, 78.6 mmol), hydrazine hydrate (80 mL), and dry THF (80 mL), was heated at 90° C. for 84 h. Work-up: the organic solvent was evaporated. The resulting mixture was diluted with EtOAc (400 mL), washed with water (150 mL), dried over Na2SO4, and concentrated in vacuo. The residue was purified by column chromatography on silica gel (0˜20% EtOAc in petroleum ether) to give 5-bromo-7-fluoro-1H-indazole as a white solid (9.3 g). 1H NMR (300 MHz, CDCl3): δ 13.83 (br, 1H), 8.16 (s, 1H), 7.87 (s, 1H), 7.45 (d, 1H).

1. customthe organic solvent was evaporated
2. additionThe resulting mixture was diluted with EtOAc (400 mL)
3. washwashed with water (150 mL)
4. dry with materialdried over Na2SO4
5. concentrationconcentrated in vacuo
6. customThe residue was purified by column chromatography on silica gel (0˜20% EtOAc in petroleum ether)

ORD record

ord-c2acd5b320c340e1908c0662b26872eb

Source dataset

uspto-grants-2013_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08455534B2