Hydrazine hydrate (1:1) → tert-Butyl 4-bromo-1H-indazole-5-carboxylate

Participants

Reaction Steps

A bi-phasic solution of 2-bromo-4-fluoro-3-formyl-benzoic acid tert-butyl ester (4.25 g, 14 mmol), DME (25 mL) and hydrazine hydrate (15 mL) was heated at 90° C. for 1 hour. After cooling, the products were partitioned between ethyl acetate and water, the aqueous layer extracted with ethyl acetate and the combined organic extracts dried (Na2SO4), filtered and concentrated in vacuo to give the title compound as a tan solid (4.1 g, 100%). LCMS (method B) RT=3.63 min, [M+CH3CN+H]+=338/340, [M−H]−=295/297.

Provenance & Evidence