反应详情

To a solution of 3-phenyl-4-(trifluoromethyl)isoxazole-5-carbonyl fluoride Int-1-G (273 mg, 1.05 mmol) in ACN (6.7 mL) was added racemic (3R*,4S*,E/Z)-3-azido-N′,4-dihydroxychroman-7-carboximidamide (250 mg, 1.0 mmol) and Hunig's Base (210 μL, 1.2 mmol). The resulting solution was stirred overnight. Next, the solvent was evaporated. The resulting residue was purified by column chromatography (ISCO Combiflash Companion, 12 g silica gel, 10% ethyl acetate-hexane for 5 min then ramp to 50% ethyl acetate-hexane over 7 min then 50% ethyl acetate-hexane for 3 more min, product came out 8-10 min) to give racemic (3R*,4S*)-3-azido-7-(5-(3-phenyl-4-(trifluoromethyl)isoxazol-5-yl)-1,2,4-oxadiazol-3-yl)chroman-4-ol (280 mg, 0.59 mmol, 59.3% yield): LCMS=470.98 [M+H]+, 1H NMR (400 MHz, CDCl3) δ ppm 7.82 (1H, dd, J=8.03, 1.65 Hz), 7.66-7.72 (3H, m), 7.52-7.62 (4H, m), 4.96-5.02 (1H, m), 4.43-4.51 (1H, m), 4.32-4.38 (1H, m), 4.08-4.17 (1H, m).

1. customNext, the solvent was evaporated
2. customThe resulting residue was purified by column chromatography (ISCO Combiflash Companion, 12 g silica gel, 10% ethyl acetate-hexane for 5 min
3. waitthen ramp to 50% ethyl acetate-hexane over 7 min
4. wait50% ethyl acetate-hexane for 3 more min, product came out 8-10 min