反应详情

To a flask containing N-hydroxy-3-(trifluoromethyl)benzenecarboximidoyl chloride (2.0 g, 8.9 mmol) and methyl acrylate (0.7 g, 8 mmol) in methylene chloride (100 mL) at 0° C. under an inert atmosphere was added TEA (0.90 g, 8.8 mmol). The reaction mixture was slowly warmed to ambient temperature, stirred for 20 h, quenched with water (30 mL), and extracted with methylene chloride (2×50 mL). The organic extracts were combined, washed with saline solution (50 mL), dried over sodium sulfate, concentrated in vacuo, and chromatographed on silica gel, eluting with methylene chloride/methanol (100/1 to 95/5). The appropriate fractions were combined and concentrated in vacuo to give methyl 3-[3-(trifluoromethyl)phenyl]4,5-dihydroisoxazole-5-carboxylate (2.3 g, 100%): LCMS: 274.2 (M+H+, 100%); 1H NMR: (CDCl3) δ 8.03 (s, 1H), 7.92 (d, 1H), 7.71 (d, 1H), 7.59 (dd, 1H), 5.28 (dd, 1H), 3.86 (s, 3H), 3.71 (dd, 2H).

1. customquenched with water (30 mL)
2. extractionextracted with methylene chloride (2×50 mL)
3. washwashed with saline solution (50 mL)
4. dry with materialdried over sodium sulfate
5. concentrationconcentrated in vacuo
6. customchromatographed on silica gel
7. washeluting with methylene chloride/methanol (100/1 to 95/5)
8. concentrationconcentrated in vacuo