反应详情

To a solution of 2.74 g ethyl 8-ethoxycarbonyl-2-methyl-3-oxo-1-oxa-8-azaspiro[4.5]decane-4-carboxylate in 10 ml N,N-dimethylformamide, were added 512 mg sodium chloride and 315 μl water, and the mixture was heated with stirring for two hours in an oil bath held at 140°-150° C. The reaction mixutre was poured into 30 ml ice water, the resulting mixture was extracted with chloroform, and the extract was washed with an aqueous solution of sodium chloride and dried over anhydrous magnesium sulfate. After distilling off the solvent from the dried solution, the residue was purified by silica gel column chromatography using, as eluent, a mixed solvent of n-hexane/ethyl acetate (1:1 by volume), giving 1.54 g of 8-ethoxycarbonyl-2-methyl-1-oxa-8-azaspiro[4.5]decan-3-one as oil.

1. temperaturethe mixture was heated
2. customheld at 140°-150° C
3. extractionthe resulting mixture was extracted with chloroform
4. washthe extract was washed with an aqueous solution of sodium chloride
5. dry with materialdried over anhydrous magnesium sulfate
6. distillationAfter distilling off the solvent from the dried solution
7. customthe residue was purified by silica gel column chromatography