反应详情

60% NaH in mineral oil (19.5 g, 488.4 mmol) is covered with 600 ml of dry diethyl ether. Ethanol (28.1 ml, 444 mmol) is added dropwise within 25 min. Then oxalic acid diethyl ester (66 ml, 488 mmol) is added dropwise within 20 min. After 10 min stirring at room temperature, the mixture is heated to reflux. A solution of 107 (88 g, 444 mmol) in 80 ml of dry diethyl ether is added dropwise within 30 min and the mixture is allowed to reflux for 1 hour. After cooling down to room temperature, the reaction mixture is poured on 2M HCl (400 ml)/ice (400 g) and extracted with diethyl ether. The organic layers are dried over sodium sulfate, filtrated and evaporated. The crude product is purified by filtration over silica gel (ethyl acetate/hexane 1:1). Evaporation gave 140 g of an red oil. The mineral oil could be removed using a separatory funnel. Yield: 132 g (100%).

1. temperaturethe mixture is heated to reflux
2. temperatureto reflux for 1 hour
3. temperatureAfter cooling down to room temperature
4. extractionextracted with diethyl ether
5. dry with materialThe organic layers are dried over sodium sulfate
6. filtrationfiltrated
7. customevaporated
8. filtrationThe crude product is purified by filtration over silica gel (ethyl acetate/hexane 1:1)
9. customEvaporation