反应详情

温度

99 °C

To a 5 L three-neck flask equipped with a thermometer and a mechanical stirrer and heated on a steam bath was added 350 g ethyl 5-acetyl-4-oxohexanoate, 329 g ethyl aminomalonate hydrochloride, 133 g sodium acetate and 1.2 L acetic acid. The mixture was heated to 99° C. over 37 minutes. By 62° C., carbon dioxide evolution was already rapid. After a total of 35 minutes at 99° C. gas, CO2 evolution had greatly slowed. After another hour, the mixture was cooled, sodium chloride removed by vacuum filtration, and the solvent evaporated. The residue was mixed with 1 L of cold water. The precipitate was collected by vacuum filtration, washed with 400 mL water, and dissolved in 1 L of hot 95% ethanol. The solution was treated with 20 g of Darco G-60, hot-filtered, and cooled to room temperature. The crystalline solid was collected by vacuum filtration, washed twice on the filter with 200 mL of 50% ethanol and dried under vacuum at 70° C. to give 285 g (64% yield) of 2-ethoxycarbonyl-4-(2-ethoxycarbonylethyl)-3,5-dimethylpyrrole. The filtrate was refrigerated overnight to give another 53.1 g (11.9% yield) of product for a total yield of 75.9%).

1. customTo a 5 L three-neck flask equipped with a thermometer and a mechanical stirrer
2. temperatureheated on a steam bath
3. customBy 62° C.
4. customAfter a total of 35 minutes
5. customat 99° C.
6. waitAfter another hour
7. temperaturethe mixture was cooled
8. customsodium chloride removed by vacuum filtration
9. customthe solvent evaporated
10. additionThe residue was mixed with 1 L of cold water
11. filtrationThe precipitate was collected by vacuum filtration
12. washwashed with 400 mL water
13. dissolutiondissolved in 1 L of hot 95% ethanol
14. additionThe solution was treated with 20 g of Darco G-60
15. filtrationhot-filtered
16. temperaturecooled to room temperature
17. filtrationThe crystalline solid was collected by vacuum filtration
18. washwashed twice on the
19. filtrationfilter with 200 mL of 50% ethanol
20. customdried under vacuum at 70° C.