反应详情

To a solution of sodium ethoxide (from 19 gm. of sodium and 260 ml of absolute ethanol) under nitrogen atmosphere, add dropwise a solution of 40 gm of 2,4-dihydroxy-3-propylacetophenone and 68 gm of diethyloxalate in 55 ml of absolute ethanol and 55 ml of absolute ether. Heat under reflux for 3.5 hours. Cool to room temperature and pour the mixture into 500 ml of 5% aqueous hydrochloric acid. Extract the mixture twice with ether. Wash the combined organic fractions with water, dry over sodium sulfate and strip to a residue. Reflux the residue for 30 minutes in 150 ml absolute ethanol containing 2.5 ml of concentrated hydrochloric acid. Evaporate most of the ethanol and partition the residue between water and ethyl acetate. Wash the organic fraction with water, aqueous sodium bicarbonate solution and again with water. Dry over sodium sulfate and strip to a residue. Crystallize the residue from ethyl acetate-hexane to obtain a first crop (mp 155°-162° C.). Strip the mother liquors to dryness and chromatograph the residue over silica gel, eluting with a mixture of ethylacetate-hexane (1:1). Crystallize the resulting product from ethyl acetate to obtain a second crop. (mp 165°-167° C. lit. 166°-167° C.).

1. temperatureHeat
2. temperatureunder reflux for 3.5 hours
3. extractionExtract the mixture twice with ether
4. washWash the combined organic fractions with water
5. dry with materialdry over sodium sulfate and strip to a residue
6. temperatureReflux the residue for 30 minutes in 150 ml absolute ethanol containing 2.5 ml of concentrated hydrochloric acid
7. customEvaporate most of the ethanol
8. custompartition the residue between water and ethyl acetate
9. washWash the organic fraction with water, aqueous sodium bicarbonate solution
10. dry with materialDry over sodium sulfate and strip to a residue
11. customCrystallize the residue from ethyl acetate-hexane
12. customto obtain a first crop (mp 155°-162° C.)
13. washStrip the mother liquors to dryness and chromatograph the residue over silica gel, eluting with a mixture of ethylacetate-hexane (1:1)
14. customCrystallize the resulting product from ethyl acetate
15. customto obtain a second crop
16. custom(mp 165°-167° C. lit. 166°-167° C.)