Triethylamine → Methyl 4-(5-(3,4,5-trichlorophenyl)-5-(trifluoromethyl)-4,5-dihydro-isoxazol-3-yl)-2-methylbenzoate

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Reaction Steps

To a solution of methyl 4-(chloro(hydroxyimino)methyl)-2-methylbenzoate (12.6 mmol) in DMF (30 mL) at 0° C. was added 1,2,3-trichloro-5-(3,3,3-trifluoroprop-1-en-2-yl)benzene (4.2 g, 15.1 mmol) followed by Et3N (2.55 g, 25.2 mmol). The reaction mixture was stirred at rt for 18 h, poured into ice-water (30 mL) and extracted with ethyl acetate (50 mL×2). 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 (10:1) to give methyl 4-(5-(3,4,5-trichlorophenyl)-5-(trifluoromethyl)-4,5-dihydro-isoxazol-3-yl)-2-methylbenzoate (4.1 g; yield 70% over 3 steps) as a pale yellow oil. 1H NMR (500 MHz, CDCl3): δ 7.98 (d, J=8.5 Hz, 1H), 7.66 (s, 2H), 7.55 (s, 2H), 4.13 (d, J=17.5 Hz, 1H), 3.93 (s, 3H), 3.73 (d, J=17.5 Hz, 1H), 2.64 (s, 3H) ppm; MS: m/z=465.9 (M+1, ESI+).

Provenance & Evidence