Hydrochloric Acid → 4-bromo-1-(2-ethoxyethyl)-1H-pyrazole

Participants

Reaction Steps

To a solution of 4-bromopyrazole (70.0 g, 0.476 mol) in CH2Cl2 (600 mL) was added a solution of 3.1 M HCl in dioxane (4 mL) and ethyl vinyl ether (41 g, 0.569 mol, 1.2 equiv) at ambient temperature. The resulting reaction mixture was stirred at ambient temperature for 3 h. The reaction was quenched with aqueous NaHCO3 and the two layers were separated. The organic layer was washed with water, dried over Na2SO4, and concentrated under reduced pressure to dryness to afford 4-bromo-1-(ethoxyethyl)-1H-pyrazole (113 g, 104.3 g theoretical, 97% yield) as an oil (GC purity: 89%), which was directly used in the subsequent reaction without further purification.

Provenance & Evidence