Trimethylsilyldiazomethane → 4-Bromo-2-fluoro-benzoic acid methyl ester

Participants

Reaction Steps

To a solution of 4-bromo-2-fluorobenzoic acid (2.0 g, 9.1 mmol) in THF (24 mL) and methanol (6 mL) at 0° C. was added a solution of (trimethylsilyl)diazomethane in hexanes (2.0 M, 5.46 mL, 10.9 mmol). The yellow solution was allowed to gradually warm to room temperature over 1 h. The volatile materials were removed and the residue was treated with aqueous hydrochloric acid (1 M). The aqueous mixture was extracted with ethyl acetate. The organic extract was dried over magnesium sulfate, filtered, and concentrated to provide crude methyl 4-bromo-2-fluorobenzoate (2.7 g, quantitative yield). This material was used in the subsequent step without further purification. 1H NMR (400 MHz, CDCl3): 7.85-7.81 (m, 1H), 7.38-7.33 (m, 2H), 3.93 (s, 3H); MS (EI) for C8H6BrFO2: 232, 234 (MH+).

Provenance & Evidence