Acetic Anhydride → 1-(5-bromo-6-fluoro-1H-indazol-1-yl)ethanone

Participants

Reaction Steps

A solution of N-(4-bromo-5-fluoro-2-methylphenyl)acetamide (24B, 10.00 g, 40.64 mmol) in chloroform (100 mL) was treated with acetic anhydride (11.5 mL, 122.0 mmol), potassium acetate (8.00 g, 81.5 mmol), and 18-Crown-6 (540.00 mg, 2.0430 mmol) and then with isoamyl nitrite (12.3 mL, 871 mmol) and heated at 65° C. for 12 hours. The reaction mixture was cooled to room temperature and treated with EtOAc (500 mL), washed with water, dried (MgSO4), filtered, and then concentrated in vacuo. A pale yellow solid of 1-(5-bromo-6-fluoro-1H-indazol-1-yl)ethanone (24C) precipitated out. The initial filtrate was concentrated and the resulting residue was purified using chromatography (SiO2, EtOAc/Hexanes) to yield more of product 24C.

Provenance & Evidence