反应详情

Potassium t-butoxide (10.9 g) was added with stirring to a solution of diethyl imidazole-4,5-dicarboxylate (20 g, described by Jones, J.A.C.S. 74, 1085 (1952)) in dry dimethylformamide (300 ml) at room temperature and the mixture was stirred for 40 minutes. 3,4-Dichlorobenzyl chloride (20.4 g) was added and the mixture was heated at reflux for 11 hours. The cooled reaction mixture was poured into ice-water (500 ml) and extracted with chloroform (2×200 ml). The combined extracts were washed with water (3×300 ml), dried over magnesium sulphate, filtered and evaporated to dryness. The solid residue was crystallised from methanol (100 ml) to give diethyl 1-(3,4-dichlorobenzyl)imidazole-4,5-dicarboxylate, m.p. 105°-107° C., (13 g) as a colourless solid.

1. temperaturethe mixture was heated
2. temperatureat reflux for 11 hours
3. customThe cooled reaction mixture
4. extractionextracted with chloroform (2×200 ml)
5. washThe combined extracts were washed with water (3×300 ml)
6. dry with materialdried over magnesium sulphate
7. filtrationfiltered
8. customevaporated to dryness
9. customThe solid residue was crystallised from methanol (100 ml)