反应详情

2.21 g (0.0199 mole) of potassium tert-butoxide were added to a solution of 3.60 g (0.0199 mole) of methyl 3-formyl-4,5-dimethylpyrrole-2-carboxylate and 0.36 g (0.0014 mole) of 18-crown-6 in 220 ml of tetrahydrofuran and the resulting mixture was stirred at room temperature for 45 minutes. 3.60 g (0.0398 mole) of 1-chloro-2-butene (a mixture of cis and trans isomers) was added to the mixture and heated under reflux for 7 hours. 1.80 g (0.0199 mole) of 1-chloro-2-butene were then added thereto and heated under reflux for 22 hours. The reaction mixture was allowed to cool to room temperature, subsequently ice-water was added thereto and the mixture was extracted with ethyl acetate. The extract was washed with water and dried over anhydrous sodium sulfate, and the solvent was distilled off. The residue was purified by column chromatography through silica gel using a 95:5 mixture of toluene and ethyl acetate as an eluent to give 4.50 g (0.0192 mole) of methyl 1-(2-butenyl)-3-formyl-4,5-dimethylpyrrole-2-carboxylate (cis/trans =24/76) as a yellow oil.

1. additionwas added to the mixture
2. temperatureheated
3. temperatureunder reflux for 7 hours
4. temperatureheated
5. temperatureunder reflux for 22 hours
6. temperatureto cool to room temperature
7. extractionthe mixture was extracted with ethyl acetate
8. washThe extract was washed with water
9. dry with materialdried over anhydrous sodium sulfate
10. distillationthe solvent was distilled off
11. customThe residue was purified by column chromatography through silica gel using
12. additiona 95:5 mixture of toluene and ethyl acetate as an eluent