Hydrochloric Acid → 4-[5-(3,5-Dichlorophenyl)-5-trifluoromethyl-4,5-dihydroisoxazol-3-yl]-2-trifluoromethyl benzoic acid

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Reaction Steps

To a solution of 4-[5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazol-3-yl]-2-trifluoromethyl-benzoic acid methyl ester (Example I13) (4.3 g) in tetrahydrofuran (3 ml) and methanol (3 ml) was added a solution of potassium hydroxide (1.0 g) in water (4.0 ml). The reaction mixture was stirred at ambient temperature for 2 hours. The reaction mixture was acidified by addition of hydrochloric acid (2M) (200 ml) and the mixture extracted with ethyl acetate (3×100 ml). The combined organic extracts were washed with brine, dried over sodium sulfate and concentrated. The residue was re-crystallized from dichloromethane and heptane to give 4-[5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazol-3-yl]-2-trifluoromethyl-benzoic acid (3.58 g) as a white powder. 1H-NMR (CDCl3, 400 MHz): 8.08-7.45 (m, 6H), 4.14 (d, 1H), 3.76 (d, 1H).

Provenance & Evidence