反应详情

A solution of diethyl malonate (15.2 mL, 99.8 mmol) in ethanol (10 mL) was added dropwise to a solution of sodium ethoxide in ethanol [freshly prepared from sodium (2.3 g, 100 mmol) and ethanol (30 mL)] at ambient temperature and stirred for 10 min. Bis(2-chloroethyl)ether (12 mL, 102 mmol) was added dropwise then the mixture was heated at reflux overnight. It was then cooled to 10° C. before another portion of freshly-prepared sodium ethoxide in ethanol [prepared from sodium (2.3 g, 100 mmol) and ethanol (30 mL)] was added. The mixture was heated at reflux for 48 h then cooled, filtered to remove the precipitated sodium chloride then the filtrate was concentrated to dryness. Water was added to the residue which was then extracted with ether (3×25 mL). The combined ether layers were washed with water, brine and dried over anhydrous sodium sulfate. Concentration under reduced pressure yielded tetrahydropyran-4,4-dicarboxylic acid diethyl ester (10.1 g, 44%) as a mobile oil.

1. temperaturethe mixture was heated
2. temperatureat reflux overnight
3. additionwas added
4. temperatureThe mixture was heated
5. temperatureat reflux for 48 h
6. temperaturethen cooled
7. filtrationfiltered
8. customto remove the precipitated sodium chloride
9. concentrationthe filtrate was concentrated to dryness
10. additionWater was added to the residue which
11. extractionwas then extracted with ether (3×25 mL)
12. washThe combined ether layers were washed with water, brine
13. dry with materialdried over anhydrous sodium sulfate
14. concentrationConcentration under reduced pressure