Benzyl Bromide → ethyl 1-benzyl-1H-pyrazole-4-carboxylate

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Reaction Conditions

Reaction Steps

1H-Pyrazole-4-carboxylic acid, ethyl ester [CAS Reg. No. 37622-90-5] (1.52 g) was dissolved in dry DMF (25 mL) and cooled to 0° C. under argon. To the mixture was added sodium hydride (651 mg, 60% in mineral oil) and the mixture was allowed to stir at 0° C. for 30 minutes. Benzyl bromide (2.23 g, 1.55 mL) was added over a period of 15 minutes and stirring was continued again for 1 hour at 0° C. The reaction mixture was poured into ice water and extracted with ethyl acetate. The organic layer was washed with brine, dried over Na2SO4 and evaporated. Toluene was added and the removed by evaporation to remove some residual water. The residue was purified by flash chromatography (50 g silica gel, gradient of ethyl acetate in heptane (10% to 40%) to give the desired material as a light yellow liquid (2.36 g). MS (m/e)=231.1[MH+].

Provenance & Evidence