反应详情

Dimethyl sulphoxide (20 mL; dried over 4 A molecular sieve) was added to potassium hydroxide (2.24 g, 0.04 mol, crushed pellets) and the mixture was stirred for 5 min. Imidazole (0.5718 g, 0.0084 mol) was then added and the mixture was stirred for 2 h. 4-Bromobenzyl bromide (3.25 g, 0.013 mol) was added and the mixture was cooled briefly and stirred for a further 1 h before water (20 mL) was added. The mixture was extracted with ether (3×100 mL) and each extract was washed with water (3×50 mL). The combined ether layers were dried over CaCl2 and the solvent was removed in vacuo. The residue was chromatographed on silica gel with CHCl3:MeOH (30:1) plus 0.05% formic acid as eluent to give the sub-title product (1.275 g, yield: 53%).

1. customdried over 4 A molecular sieve)
2. stirringthe mixture was stirred for 2 h
3. temperaturethe mixture was cooled briefly
4. additionwas added
5. extractionThe mixture was extracted with ether (3×100 mL)
6. washeach extract was washed with water (3×50 mL)
7. dry with materialThe combined ether layers were dried over CaCl2
8. customthe solvent was removed in vacuo
9. customThe residue was chromatographed on silica gel with CHCl3:MeOH (30:1) plus 0.05% formic acid as eluent