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

Participants

Reaction Conditions

Reaction Steps

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

Provenance & Evidence