Реакция #64282

Уравнение реакции

Ethyl 2,8-dimethyl-3-oxo-1-oxa-8-azaspiro[4,5]decane-4-carboxylate

caustic soda

→

2,8-dimethyl-1-oxa-8-azaspiro[4,5]decan-3-one

Выход 81.4%

Растворители

HCl

Условия реакции

Обработка

1. 1
   Температураthe solution was heated
2. 2
   Температураunder reflux for eight hours
3. 3
   Температураcooled in an ice-water bath
4. 4
   ЭкстракцияThis alkaline solution was extracted thrice with about 80 ml of chloroform
5. 5
   Экстракцияthe combined extract
6. 6
   Промывкаwas washed with saturated aqueous solution of sodium chloride
7. 7
   Сушкаdried over anhydrous magnesium sulfate
8. 8
   workup.DISTILLATIONDistilling off the solvent under reduced pressure from the dried solution
9. 9
   workup.WAITleft 2 g of yellow residue, which
10. 10
    Другоеwas purified by silica gel column chromatography

Методика

Ethyl 2,8-dimethyl-3-oxo-1-oxa-8-azaspiro[4,5]decane-4-carboxylate (3.08 g) was dissolved in 50 ml of 1N-HCl, and the solution was heated under reflux for eight hours. The reaction mixture was allowed to cool to room temperature, then cooled in an ice-water bath, and basified by addition of 20% aqueous solution of caustic soda. This alkaline solution was extracted thrice with about 80 ml of chloroform, and the combined extract was washed with saturated aqueous solution of sodium chloride and dried over anhydrous magnesium sulfate. Distilling off the solvent under reduced pressure from the dried solution left 2 g of yellow residue, which was purified by silica gel column chromatography by using, as eluent, a mixed solvent of chloroform/methanol (20:1 by volume), giving 1.8 g of 2,8-dimethyl-1-oxa-8-azaspiro[4,5]decan-3-one as oil. It was dissolved in ether, and ethanolic hydrogen chloride was added, thus giving its hydrochloride as crystals.

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