Ethyl Acetate → (1-(2-bromoethyl)-3-nitro-1H-pyrazol-5-yl)methanol

Temperature

0 °C

A mixture of 296a (345 mg, 2.41 mmol), and cesium carbonate (965 mg, 2.96 mmol) in DMF (5 mL) was cooled to 0° C. using an ice/acetone bath and dibromoethane (4.48 g, 24.1 mmol) was added portion-wise (no exotherm). The reaction was stirred at 0° C. for 1 h and room temperature for 4 h. After this time ethyl acetate (20 mL) and water (15 mL) were added. The aqueous layer was separated and extracted with ethyl acetate (2×10 mL). The combined organic layer was washed with water (10 mL), brine (10 mL), and dried over sodium sulfate. The drying agent was removed by filtration. The filtrate was concentrated under reduced pressure to afford the crude product, which was purified by silica-gel column chromatography eluting with 6:1 petroleum ether/ethyl acetate to afford 296b (300 mg, 50%). MS-ESI: [M+H]+ 250

1. customThe aqueous layer was separated
2. extractionextracted with ethyl acetate (2×10 mL)
3. washThe combined organic layer was washed with water (10 mL), brine (10 mL)
4. dry with materialdried over sodium sulfate
5. customThe drying agent was removed by filtration
6. concentrationThe filtrate was concentrated under reduced pressure
7. customto afford the crude product, which
8. customwas purified by silica-gel column chromatography
9. washeluting with 6:1 petroleum ether/ethyl acetate

ORD record

ord-1653f65bccf24fdf8a1bcec3826a3b4e

Source dataset

uspto-grants-2016_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09238655B2