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

Participants

Reaction Steps

To a stirred suspension of NaH (53 mg, 1.33 mmol, 60% dispersion in mineral oil) in THF (5 mL), was added dropwise over 3 min a solution of ethyl 1H-pyrazole-4-carboxylate (155 mg, 1.11 mmol). The mixture was stirred at rt for 45 min and then treated with benzyl bromide (neat). After 2 h, the reaction was quenched with saturated solution of NH4Cl and extracted with EtOAc (3×50 mL). The combined organic layers were washed with water, brine, dried (Na2SO4), filtered and concentrated. Purification by flash chromatography (Isco CombiFlash) 0-60% EtOAc/heptane provided ethyl 1-benzyl-1H-pyrazole-4-carboxylate (256 mg, 98%). 1H NMR (400 MHz, CDCl3) δ ppm 1.33 (t, J=7.09 Hz, 3H), 4.28 (q, J=7.08 Hz, 2H), 5.31 (s, 2H), 7.24-7.28 (m, 2H), 7.31-7.42 (m, 3H), 7.86 (s, 1H), 7.95 (s, 1H); LCMS-MS (ESI+) 230.80 (M+H).

Provenance & Evidence