反应详情

To a solution of 5-Bromo-1-methyl-imidazole (18.8 g, 117 mmol) in dichloromethane (50 mL) was added dropwise ethylmagnesium bromide (3 M in Et2O, 38.9 mL, 117 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-methylthiophene-3-carboxamide (20.0 g, 117 mmol) was added dropwise. The mixture was stirred for 3.5 h at room temperature. The mixture was worked-up by addition of water (400 mL), then acidified with aq. HCl (1 M) until pH=7. After extraction with dichloromethane (3×100 mL), the organic layers were washed with water (100 mL) then dried over MgSO4 and concentrated in vacuo. Purification of the residue on silica gel afforded (1-methyl-1H-imidazol-5-yl)(3-thienyl)methanone [11.6 g, yield 41%; HPLC/MS: m/z=193 (M+H); log P(HCOOH)=0.43].

1. temperaturethe reaction mixture was cooled down to 0° C. with an ice-brine bath
2. stirringThe mixture was stirred for 3.5 h at room temperature
3. extractionAfter extraction with dichloromethane (3×100 mL)
4. washthe organic layers were washed with water (100 mL)
5. dry with materialthen dried over MgSO4
6. concentrationconcentrated in vacuo
7. customPurification of the residue on silica gel