反应详情

温度

80 °C

2,4-Diethoxycarbonyl-3,5-dimethylpyrrole (2.0 g) was dissolved in ethanol (20 ml), and a 1 N sodium hydroxide solution (20 ml) was added and stirred overnight at 80° C. After cooling to room temperature, the reaction mixture was neutralized with a hydrochloric acid solution. The precipitate was collected by filtration, and dried in vacuo. The obtained solid was dissolved in trifluoroacetic acid (20 ml), and stirred for 1 hour at 40° C. While cooling with ice, triethyl orthoformate (2.5 ml) was slowly added dropwise to the reaction mixture. The mixture was allowed to room temperature, and then stirred for 2 hours. The resultant was concentrated at reduced pressure. The residue was added to a saturated sodium hydrogencarbonate and stirred, and then the precipitate was collected by filtration. The obtained solid was purified using medium pressure silica gel flash column chromatography (hexane:ethyl acetate=5:1 to 1:1), and dried in vacuo to afford 5-formyl-2,4-dimethyl-pyrrole-3-carboxylic acid ethyl ester (1.21 g, 74%) as a light yellow solid.

1. temperatureAfter cooling to room temperature
2. filtrationThe precipitate was collected by filtration
3. customdried in vacuo
4. dissolutionThe obtained solid was dissolved in trifluoroacetic acid (20 ml)
5. stirringstirred for 1 hour at 40° C
6. temperatureWhile cooling with ice, triethyl orthoformate (2.5 ml)
7. additionwas slowly added dropwise to the reaction mixture
8. customwas allowed to room temperature
9. stirringstirred for 2 hours
10. concentrationThe resultant was concentrated at reduced pressure
11. additionThe residue was added to a saturated sodium hydrogencarbonate
12. stirringstirred
13. filtrationthe precipitate was collected by filtration
14. customThe obtained solid was purified
15. customdried in vacuo