Sulfuric Acid → 6-Methoxy-benzofuran-2,3-dicarboxylic acid diethyl ester
Reaction equation
[CH2:1]([O:3][C:4](=[O:22])[CH:5]([O:13][C:14]1[CH:19]=[CH:18][CH:17]=[C:16]([O:20][CH3:21])[CH:15]=1)[C:6](=O)[C:7]([O:9][CH2:10][CH3:11])=[O:8])[CH3:2].S(=O)(=O)(O)O>>[CH2:1]([O:3][C:4]([C:5]1[O:13][C:14]2[CH:15]=[C:16]([O:20][CH3:21])[CH:17]=[CH:18][C:19]=2[C:6]=1[C:7]([O:9][CH2:10][CH3:11])=[O:8])=[O:22])[CH3:2]Participants
3
Procedure
2-(3-Methoxy-phenoxy)-3-oxo-succinic acid diethyl ester (23) (60 g, 193.4 mmol) is dissolved in 32 ml of cooled (−15° C.) cone, sulfuric acid and stirred for 3 h whereas the reaction mixture slowly warmed up to room temperature. Then the mixture is poured onto 1 kg of ice and extracted with diethyl ether. The organic layers are washed with brine, dried over sodium sulfate, filtrated and evaporated. The crude product is purified by Flash-chromatography (silica gel, ethyl acetate/hexanes 1:9).
Workup
- extractionextracted with diethyl ether
- washThe organic layers are washed with brine