Sodium hydride → ethyl 1-(2-tert-butoxy-2-oxoethyl)-1H-pyrazole-4-carboxylate

Participants

Reaction Conditions

Reaction Steps

Ethyl 1H-pyrazole-4-carboxylate (20.0 g) was dissolved in N,N-dimethylformamide (200 mL), and sodium hydride (60% in mineral oil, 8.6 g) was added by small portions under cooling in an ice bath. The reaction mixture was stirred at the same temperature for 30 min, and tert-butyl 2-bromoacetate (33 g) was added dropwise. The mixture was stirred at room temperature for 10 min, heated at 50° C. overnight. The reaction mixture was poured into ice water, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was separated, washed with saturated brine, dried over sodium sulfate, and concentrated under reduced pressure. The residue was purified by column chromatography (carrier: silica gel, eluent: hexane-petroleum ether) to give the title compound (17.6 g) as a colorless solid.

Provenance & Evidence