反应详情

To a solution of 4-bromopyrazole (21, 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 (18, 41 g, 0.569 mol, 1.2 equiv). The resulting reaction mixture was stirred at room temperature for 3 hrs. 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 (22, 113 g, 104.3 g theoretical, 97% yield) as an oily (GC purity: 89%), which was directly used in the subsequent reaction without further purification.

1. customThe resulting reaction mixture
2. customThe reaction was quenched with aqueous NaHCO3
3. customthe two layers were separated
4. washThe organic layer was washed with water
5. dry with materialdried over Na2SO4
6. concentrationconcentrated under reduced pressure to dryness