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 5.5 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 (2×100 mL) then dried over MgSO4 and concentrated in vacuo. Purification of the residue on silica gel afforded (1-methyl-1H-imidazol-5-yl)(2-thienyl)methanone [10.2 g, yield 36%; HPLC/MS: m/z=193 (M+H); log P(HCOOH)=0.52].

1. temperaturethe reaction mixture was cooled down to 0° C. with an ice-brine bath
2. stirringThe mixture was stirred for 5.5 h at room temperature
3. extractionAfter extraction with dichloromethane (3×100 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