反应详情

Alanine ethyl ester hydrochloride (30.8g; 0.2 mole) was dissolved in 100 ml of acetic acid. Acetonylacetone (22.8 g; 0.2 mole) and then 16.4 g (0.2 mole) of sodium acetate were added to the solution, and the mixture heated under reflux for 5 hours. The acetic acid was distilled off under reduced pressure, and ethyl acetate added to the residue. The organic layer was washed with an aqueous solution of sodium hydrogen carbonate, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to afford 29.2 g of a crude product. The product was chromatographed on a column of silica gel using cyclohexane/ethyl acetate (4/1) as an eluent to afford ethyl 2-(2,5-dimethylpyrrol-1-yl)propionate (23.0 g, 0.118 mole, 59.0%).

1. temperaturethe mixture heated
2. temperatureunder reflux for 5 hours
3. distillationThe acetic acid was distilled off under reduced pressure, and ethyl acetate
4. additionadded to the residue
5. washThe organic layer was washed with an aqueous solution of sodium hydrogen carbonate
6. dry with materialdried over anhydrous magnesium sulfate
7. concentrationconcentrated under reduced pressure
8. customto afford 29.2 g of a crude product
9. customThe product was chromatographed on a column of silica gel