反应详情

To a well stirred solution of 2,3,5-trimethyl-6-(5'-carboxypentyl)-1,4-benzoquinone (formula I-2 wherein R=H3C, n=4, in the free form) (0.21 part) in ethanol (10 volume parts) was added 3 drops of concentrated sulfuric acid under cooling in ice bath and kept standing for 12 hours. After addition of water, the reaction mixture was extracted with diethyl ether and the diethylether layer was washed with water and dried over anhydrous sodium sulfate. The residue upon removal of the solvent was subjected to chromatography on silica gel and eluted with chloroform to give 2,3,5-trimethyl-6-(5'-ethoxycarbonylpentyl)-1,4-benzoquinone (formula I-2 wherein R=H3C, n=4, in the form of ethyl ester) (0.20 part) as an orange oil.

1. temperatureunder cooling in ice bath
2. extractionthe reaction mixture was extracted with diethyl ether
3. washthe diethylether layer was washed with water
4. dry with materialdried over anhydrous sodium sulfate
5. customThe residue upon removal of the solvent
6. washeluted with chloroform