反应详情

KOH (5 g, 2 eq) was added to a suspension of 5-formyl-4-methyl-1H-pyrrole-3-carboxylic acid ethyl ester (8.13 g, 44.8 mmol) in water (100 mL) and EtOH (50 mL) with stirring. The mixture was heated to reflux for 2.5 hr, cooled to rt, concentrated to about ⅔ volume, diluted with water (300 mL) and acidified to pH=3 using 1N HCl. The white solid was collected by filtration and dried to afford 6 g (87%) of 5-formyl-4-methyl-1H-pyrrole-3-carboxylic acid as a tan solid.

1. temperatureThe mixture was heated
2. temperatureto reflux for 2.5 hr
3. concentrationconcentrated to about ⅔ volume
4. additiondiluted with water (300 mL)
5. filtrationThe white solid was collected by filtration
6. customdried