反应详情

A solution of ethane-1,2-diol (0.081 mL, 1.45 mmol, 1.5 equiv), 1-(4-chlorophenyl)-1H-imidazole-4-carbaldehyde (200 mg, 0.968 mmol), and camphorsulfonic acid (45 mg, 0.19 mmol, 0.2 equiv) in toluene (10 mL) was heated at reflux with a Dean-Stark apparatus for 1 hour. The reaction was cooled to room temperature and quenched with saturated aqueous sodium bicarbonate (30 mL). The mixture was extracted with ethyl acetate (30 mL) and the organic layer was dried (Na2SO4), filtered, and concentrated in vacuo. Silica gel column chromatography (EtOAc with 7% methanol) provided 1-(4-chlorophenyl)-4-(1,3-dioxolan-2-yl)-1H-imidazole (0.100 g, tan solid) in 41% yield. 1H NMR (400 MHz, CDCl3) δ 7.80 (s, 1H), 7.46 (d, J=8.4 Hz, 2H), 7.36 (s, 1H), 7.33 (d, J=8.4 Hz, 2H), 5.96 (s, 1H), 4.20 (m, 2H), 4.05 (m, 2H). MS m/z 251.0 (M+H)+; Rt-0.53 min.

1. temperatureat reflux with a Dean-Stark apparatus for 1 hour
2. customquenched with saturated aqueous sodium bicarbonate (30 mL)
3. extractionThe mixture was extracted with ethyl acetate (30 mL)
4. dry with materialthe organic layer was dried (Na2SO4)
5. filtrationfiltered
6. concentrationconcentrated in vacuo