反应详情

To a solution of 5-bromo-1,2-dimethyl-1H-imidazole (10.0 g, 57.1 mmol) in dichloromethane (50 mL) was added dropwise ethylmagnesium bromide (3 M in Et2O, 19.0 mL, 57.0 mmol). After stirring at room temperature for 30 min, the reaction mixture was cooled down to 0° C. with an ice-brine bath and N-Methoxy-N-methyl-benzamide (8.70 mL, 57.1 mmol) was added dropwise. The mixture was stirred for 7.5 h at room temperature. The mixture was worked-up by addition of water (100 mL), then acidified with aq. HCl (1 M) until pH=7. After extraction with dichloromethane (2×75 mL), the organic layers were washed with water (2×100 mL) then dried over MgSO4 and concentrated in vacuo. Purification of the residue on silica gel afforded (1,2-dimethyl-1H-imidazol-5-yl)(phenyl)methanone [8.41 g, yield 44%; HPLC/MS: m/z=201 (M+H); log P(HCOOH)=0.56].

1. temperaturethe reaction mixture was cooled down to 0° C. with an ice-brine bath
2. stirringThe mixture was stirred for 7.5 h at room temperature
3. extractionAfter extraction with dichloromethane (2×75 mL)
4. washthe organic layers were washed with water (2×100 mL)
5. dry with materialthen dried over MgSO4
6. concentrationconcentrated in vacuo
7. customPurification of the residue on silica gel