Sodium Hydroxide → (S)-2,4,5-Trifluoro-N-(1,1,1-trifluoropropan-2-yl)benzamide

Participants

Reaction Steps

To a solution of 2,4,5-trifluorobenzoic acid (5.00 g, 28.4 mmol) in acetonitrile (50 mL) was added N,N-dimethylformamide (40 μL) followed by addition of oxalyl chloride (3.60 mL, 42.6 mmol). After 90 min, the volatiles were removed under reduced pressure. The residue was co-evaporated with acetonitrile (50 mL). The residue was then dissolved in methylene chloride (50 mL). This solution was added drop-wise into a cooled (ice bath) mixture of (2S)-1,1,1-trifluoropropan-2-amine hydrochloride (5.52 g, 36.9 mmol) (from Synquest, 98% ee) in toluene (100 mL) and 0.5 M sodium hydroxide aqueous solution (142 mL, 71.0 mmol). After addition, the ice bath was removed, and the reaction was allowed to warm to rt. The reaction was stirred overnight. The organic layer was separated. The aqueous layer was extracted with methylene chloride (50 mL). The combined organic layers were washed with 20% brine (75 mL) and water (2×75 mL), dried over MgSO4, filtered and concentrated under reduced pressure to afford the desired product (6.49 g, 84%) which was directly used in the next step without further purification. 1H NMR (300 MHz, DMSO-d6) δ 9.01 (d, J=7.6 Hz, 1H), 7.92-7.50 (m, 2H), 4.76 (m, 1H), 1.31 (d, J=7.0 Hz, 3H) ppm. LCMS cacld. for C10H8F6NO (M+1)+: m/z=272.0. Found: 272.0.

Provenance & Evidence