反应详情

Sodium (2.8 eq) was added to ethanol under nitrogen at room temperature and stirred for 25 minutes to generate sodium ethoxide. 1-(2,4-Bis-benzyloxy-5-isopropyl-phenyl)-ethanone (1 eq) was dissolved in further ethanol and added to the sodium ethoxide solution. Diethyl oxalate (1.64 eq) was added and the reaction mixture heated to reflux for 4 hours. The mixture was allowed to cool to room temperature and enough 1 MHCl (aq) was added to acidify the reaction mixture, which was then concentrated in vacuo. The resulting gum was partitioned between dichloromethane and brine, and the organic phase was dried over MgSO4, filtered and evaporated in vacuo to give 4-(2,4-Bis-benzyloxy-5-isopropyl-phenyl)-2-hydroxy-4-oxo-but-2-enoic acid ethyl ester as a yellow gum.

1. temperaturethe reaction mixture heated
2. temperatureto reflux for 4 hours
3. additionenough 1 MHCl (aq) was added
4. concentrationwas then concentrated in vacuo
5. customThe resulting gum was partitioned between dichloromethane and brine
6. dry with materialthe organic phase was dried over MgSO4
7. filtrationfiltered
8. customevaporated in vacuo