Triethylamine → 7-bromo-3-(5-phenyl-4-(trifluoromethyl)isoxazol-3-yl)-4H-chromeno[4,3-c]isoxazole

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a mixture of sodium hypochlorite (23 mL), triethylamine (Preparation 62E, 0.021 mL, 0.155 mmol), and dichloromethane (1.0 mL) at 0° C. was added dropwise a solution of (E)-4-bromo-2-(3-(5-phenyl-4-(trifluoromethyl)isoxazol-3-yl)prop-2-ynyloxy)benzaldehyde oxime (0.036 g, 0.077 mmol) in dichloromethane (3 mL). The reaction mixture was stirred at 0° C. for 30 min. and then at room temperature for 1.5 h. The reaction mixture was diluted with dichloromethane, and the organic layer was collected. The aqueous layer was extracted with dichloromethane (2×), and the combined organic layers were washed with brine and dried over anhydrous sodium sulfate. Concentration under reduced pressure followed by trituration with methanol with sonication afforded 7-bromo-3-(5-phenyl-4-(trifluoromethyl)isoxazol-3-yl)-4H-chromeno[4,3-c]isoxazole (0.026 g, 0.056 mmol, 73% yield) as a white solid. The product had an HPLC ret. time=3.91 min.−Column: Chromolith SpeedROD 4.6×50 mm (4 min.); Solvent A=10% MeOH, 90% H2O, 0.1% TFA; Solvent B=90% MeOH, 10% H2O, 0.1% TFA. LC/MS M+1=464.9. 1H NMR (500 MHz, CDCl3) δ ppm 5.49 (s, 2H), 7.23-7.27 (m, 2H), 7.55-7.59 (m, 2H), 7.60-7.65 (m, 1H), 7.73 (d, J=7.49 Hz, 2H), and 7.78 (d, J=8.05 Hz, 1H).

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