Trifluoroacetic acid → 1-(oxan-2-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

Temperature

90 °C

3,4-Dihydro-2H-pyran (5.6 g, 67 mmol) and trifluoroacetic acid (1.17 g, 10.3 mmol) were added to a solution of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (10.0 g, 51.5 mmol) in toluene (200 mL), and the reaction mixture was heated to 90° C. for 2 hours. After cooling to room temperature, the reaction mixture was partitioned between ethyl acetate (200 mL) and saturated aqueous sodium bicarbonate solution (100 mL), and the aqueous layer was extracted with ethyl acetate (100 mL). The combined organic layers were washed with saturated aqueous sodium chloride solution (100 mL), dried over sodium sulfate, filtered, and concentrated in vacuo. Silica gel chromatography (Gradient: 10% to 50% ethyl acetate in petroleum ether) provided the product as a white solid. Yield: 13.4 g, 48.2 mmol, 94%. 1H NMR (400 MHz, CDCl3) δ 7.94 (s, 1H), 7.83 (s, 1H), 5.41 (dd, J=9.5, 2.5 Hz, 1H), 4.01-4.08 (m, 1H), 3.65-3.74 (m, 1H), 1.98-2.18 (m, 3H), 1.6-1.76 (m, 3H), 1.32 (s, 12H).

1. temperatureAfter cooling to room temperature
2. customthe reaction mixture was partitioned between ethyl acetate (200 mL) and saturated aqueous sodium bicarbonate solution (100 mL)
3. extractionthe aqueous layer was extracted with ethyl acetate (100 mL)
4. washThe combined organic layers were washed with saturated aqueous sodium chloride solution (100 mL)
5. dry with materialdried over sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated in vacuo

ORD record

ord-36abf72ca34b4d95b81f2d5614768afb

Source dataset

uspto-grants-2015_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09156845B2