反应详情

A dry 250 mL flask was charged with triphenylphosphonium dibromide (6.3 g, 14.9 mmol) and a solution of [2-(2-chlorophenyl)-5-trifluoromethyl-2H-pyrazol-3-yl]-methanol (3.54 g in 100 mL of CH2Cl2) was added portionwise. The reaction was stirred at room temperature for 2 h then was washed into a separatory funnel with water and CH2Cl2. The CH2Cl2 was separated, dried (MgSO4), and concentrated in vacuo. The crude bromide was purified by silica gel flash chromatography (Jones Flashmaster, 70 g Silica gel, gradient elution from 100% hexanes to 10% ethyl acetate over 30 minutes). Appropriate fractions were combined and concentrated in vacuo to afford 5-bromomethyl-1-(2-chlorophenyl)-3-trifluoromethyl-1H-pyrazole as a colorless oil, yield: 2.74 g (64% for both steps); 1H NMR (400 MHz, CDCl3): δ 7.35-7.55 (m, 4H), 6.70 (s, 1H), 4.21 (br s, 2H).

1. washthen was washed into a separatory funnel with water and CH2Cl2
2. customThe CH2Cl2 was separated
3. dry with materialdried (MgSO4)
4. concentrationconcentrated in vacuo
5. customThe crude bromide was purified by silica gel flash chromatography (Jones Flashmaster, 70 g Silica gel, gradient elution from 100% hexanes to 10% ethyl acetate over 30 minutes)
6. concentrationconcentrated in vacuo