Reaktion #85690

Reaktionsgleichung

ethane-1,2-diol

1-(4-chlorophenyl)-1H-imidazole-4-carbaldehyde

camphorsulfonic acid

→

1-(4-chlorophenyl)-4-(1,3-dioxolan-2-yl)-1H-imidazole

Ausbeute 41.2%

Lösungsmittel

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturat reflux with a Dean-Stark apparatus for 1 hour
2. 2
   Sonstigequenched with saturated aqueous sodium bicarbonate (30 mL)
3. 3
   ExtraktionThe mixture was extracted with ethyl acetate (30 mL)
4. 4
   Trocknenthe organic layer was dried (Na2SO4)
5. 5
   Filtrationfiltered
6. 6
   Einengenconcentrated in vacuo

Vorschrift

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.

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