反应详情

In absolute methanol were dissolved 5.2 g of β-hydroxyisovaleric acid and 15.2 g of monoethyl acetylmalate, and 0.14 g of sodium hydroxide was added to the solution. The mixture was subjected to Kolbe electrolysis by applying a voltage of ±20 V for 5 hr through the use of a platinum electrode. After the reaction, 8 g of sodium hydroxide was added to the reaction mixture, and 200 ml of a mixed solution comprising water and methanol (1:1) was added thereto. The mixture was allowed to stand overnight for hydrolysis. A major portion of methanol contained in the solution was removed by distillation, and a neutral component contained in the solution was extracted with diethyl ether, and hydrochloric acid was added to the remaining aqueous alkaline solution to adjust the pH to 1. Thereafter, sodium chloride was added thereto until a saturated solution was prepared, and the reaction product was extracted with chloroform. The resultant chloroform solution was washed with water and dried over magnesium sulfate, and the chloroform was removed by distillation under a reduced pressure. Then 8.3 g of the crude product thus obtained was dissolved in 150 ml of benzene, 0.1 g of p-toluenesulfonic acid was added thereto, and the mixture was refluxed for 5 hr. The refluxed solution was cooled to room temperature and extracted with an ether, and the extract was washed with a saturated aqueous solution of sodium hydrogencarbonate and then with water, and the solvent was removed from the extract by distillation under a reduced pressure to obtain a crude product. The crude product was purified by a silica gel column chromatography to obtain 5.2 g of (S)-2-hydroxy-5,5-dimethyl-δ-valerolactone.

1. additionwas added to the solution
2. customfor 5 hr
3. additionwas added
4. customto stand overnight for hydrolysis
5. customwas removed by distillation
6. extractionwas extracted with diethyl ether, and hydrochloric acid
7. additionwas added to the remaining aqueous alkaline solution
8. additionThereafter, sodium chloride was added
9. customuntil a saturated solution was prepared
10. extractionthe reaction product was extracted with chloroform
11. washThe resultant chloroform solution was washed with water
12. dry with materialdried over magnesium sulfate
13. customthe chloroform was removed by distillation under a reduced pressure
14. customThen 8.3 g of the crude product thus obtained
15. temperaturethe mixture was refluxed for 5 hr
16. extractionextracted with an ether
17. washthe extract was washed with a saturated aqueous solution of sodium hydrogencarbonate
18. customwith water, and the solvent was removed from the
19. extractionextract by distillation under a reduced pressure
20. customto obtain a crude product
21. customThe crude product was purified by a silica gel column chromatography