methyl 3-(bromomethyl)-5-fluorobenzoate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 2.0M dimethylamine in THF (3.24 mL, 6.48 mmol) was added methylene chloride (2 mL) and methyl 3-(bromomethyl)-5-fluorobenzoate (0.200 g, 0.810 mmol from Step 2). The reaction was heated in a sealed reaction vessel in an oil bath held at 60° C. for 2 hours. Solvent and excess reagent were removed in vacuo and the residue was subjected to flash chromatography, eluting with a gradient from 0-20% MeOH in DCM containing some NH4OH (50 mg, 29%). 1H NMR (300 MHz, CDCl3): δ 7.80-7.77 (m, 1H), 7.62 (ddd, 1H), 7.29 (ddd, 1H), 3.90 (s, 3H), 3.53 (s, 2H), 2.29 (s, 6H); 19F NMR (282 MHz, CDCl3): δ−113.10 (t, 1F); LCMS (M+H)+: 212.1. The reaction was heated in a sealed reaction vessel in an oil bath Solvent and excess reagent were removed in vacuo eluting with a gradient from 0-20% MeOH in DCM containing some NH4OH (50 mg, 29%)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of methyl 3-fluoro-5-methylbenzoate (1.64 g, 9.75 mmol, from Step 1) and N-bromosuccinimide (2.05 g, 11.5 mmol) in carbon tetrachloride (20 mL) was added benzoyl peroxide (0.1 g, 0.6 mmol) and the mixture was heated to reflux for four hours. The reaction was then cooled to room temperature, filtered, and diluted with DCM. The solution was washed successively with sodium thiosulfate, 1N NaOH, water, and brine, dried over sodium sulfate, decanted and concentrated. Flash chromatography, eluting with a gradient from 0-20% ethyl acetate in hexanes, afforded a partially purified product. The cleanest fractions were used in the displacement with amine in Step 3. 1H NMR (300 MHz, CDCl3): δ 7.87-7.85 (m, 1H), 7.68-7.62 (m, 1H), 7.31 (ddd, 1H), 4.47 (s, 2H), 3.93 (s, 3H). the mixture was heated to reflux for four hours filtered diluted with DCM The solution was washed successively with sodium thiosulfate, 1N NaOH, water, and brine dried over sodium sulfate decanted concentrated Flash chromatography, eluting with a gradient from 0-20% ethyl acetate in hexanes afforded a partially purified product