反应详情

In a round bottom flask under nitrogen atmosphere, 3-{4-[(2-methoxyethyl)amino]-1,2,5-oxadiazol-3-yl}-4-[3-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5(4H)-one (1.3 g, 3.6 mmol) was stirred in dichloromethane (11 mL). The temperature was brought to −78° C. and a solution of 1.0 M boron tribromide in dichloromethane (7.9 mL, 7.9 mmol) was added dropwise over 15 minutes. The reaction was warmed to room temperature over 45 minutes and continued to stir at room temperature for an additional 45 minutes. The reaction was cooled to 0° C. and a saturated solution of sodium bicarbonate in water (25 mL) was added dropwise over 15 minutes. After warming to room temperature, ethyl acetate (10 mL) and water (10 mL) were added to the flask. The organic layer was collected and the aqueous layer was extracted with ethyl acetate (2×20 mL). After drying the combined organic layers over sodium sulfate, the solvent was removed in vacuo to give the desired product (1.0 g, 81%). LCMS calculated for C13H11F3N5O4 (M+H)+: m/z=358.0. 1H NMR (400 MHz, DMSO-d6): δ 8.08 (s, 1H), 7.93 (t, J=8.2 Hz, 2H), 7.79 (t, J=8.2 Hz, 1H), 6.35 (t, J=5.7 Hz, 1H), 4.86 (br s, 1H), 3.55 (t, J=6.0 Hz, 2H), 3.28 (m, 2H).

1. customwas brought to −78° C.
2. temperatureThe reaction was cooled to 0° C.
3. temperatureAfter warming to room temperature
4. customThe organic layer was collected
5. extractionthe aqueous layer was extracted with ethyl acetate (2×20 mL)
6. dry with materialAfter drying the combined organic layers over sodium sulfate
7. customthe solvent was removed in vacuo