反应详情

The latter ester (25 g) is stirred in 500 ml of 5% aqueous KOH in methanol (250 ml H2O, 250 ml CH3OH, 25 g KOH) at room temperature for about 2 hr. The mixture is diluted with water and extracted several times with ether to remove all neutral material. The aqueous fraction is cooled with crushed ice, acidified with 10% HCl and extracted with ether. The ether extract is washed with water and brine, dried (MgSO4) and concentrated to give 5-methoxy-2-thiopheneglyoxylic acid (3; X1 = CH3O, X2 and X3 = H and R10 = H); γmaxCHCl3 3000, 1630, 1625, 1530 cm-1.

1. extractionextracted several times with ether
2. customto remove all neutral material
3. temperatureThe aqueous fraction is cooled with crushed ice
4. extractionextracted with ether
5. extractionThe ether extract
6. washis washed with water and brine
7. dry with materialdried (MgSO4)
8. concentrationconcentrated