Boron tribromide → 3-Fluoro-N-(4-fluorophenyl)-4-hydroxy-N-(4-hydroxyphenyl)benzamide

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Reaction Conditions

Reaction Steps

Compound 3-fluoro-N-(4-fluorophenyl)-4-methoxy-N-(4-methoxyphenyl)benzamide (2a) (138.0 g, 0.374 mol) was dissolved in dry CH2Cl2 (600 mL) at room temperature under an argon. BBr3 (374.75 g, 1.496 mol) was added dropwise with stirring via a syringe at 0° C. in an ice-bath under an argon. The reaction solution was allowed to stir at room temperature overnight. Then, the solution was poured to 1 L of ice water with stifling. The slurry mixture was stirred at room temperature for 2 hours. The white precipitate was filtered, washed with water (2×100 mL) and dried under vacuum. The CH2Cl2 layer was separated, dried over anhydrous MgSO4 (50 g), filtered and concentrated under reduced pressure to dryness. The white precipitate and residue from CH2Cl2 solution were combined and purified by flash column chromatography (silica gel, CH2Cl2/Acetone/MeOH=90/7/3 v/v/v) to give a light tan solid which was recrystallized from hot EtOAc/Hexanes solution twice to afford a white crystalline solid, 104.0 g, 81.6% yield. M.p. 110-112° C. MS (ESI) m/z 364.1 [M+Na]+, 1H NMR (DMSO-d6) δ 10.14 (bs, 1H), 9.71 (bs, 1H), 7.25-7.11 (m, 5H), 7.05-6.99 (m, 3H), 6.78 (t, J=8.6 Hz, 1H), 6.68 (d, J=8.7 Hz, 2H).

Provenance & Evidence