Triethylamine → 4-(5-(3,5-Dichloro-4-fluorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-2-methylbenzoic acid

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Reaction Steps

To a solution of 4-(chloro(hydroxyimino)methyl)-2-methylbenzoic acid (5.1 g, 23.8 mmol) in DMF (30 mL) at 0° C. was added 1,3-dichloro-2-fluoro-5-(3,3,3-trifluoroprop-1-en-2-yl)benzene (7.4 g, 28.6 mmol) followed by Et3N (4.8 g, 47.6 mmol). The reaction mixture was stirred at rt for 18 h, poured into ice-water (30 mL) and extracted with ethyl acetate (60 mL×3). The combined organic layers were washed with brine, dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel eluted with PE:EA (1:1) to EA: MeOH (10:1) to give 4-(5-(3,5-dichloro-4-fluorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-2-methylbenzoic acid (6 g; yield 58% over 3 steps) as a white solid. MS: m/z=435.8 (M+1, ESI+).

Provenance & Evidence