反应详情

To a mixture of 0.5 g. of (±)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid and 1.3 g. of anhydrous potassium carbonate in 3 ml. of dimethylsulfoxide was added 1.0 g. of benzyl chloride. This mixture was stirred at 23° overnight to give a solution containing (±)-benzyl 6-benzyloxy-2,5,7,8-tetramethylchroman-2-carboxylate. To this solution was added 3 ml. of 1N sodium hydroxide solution and 2 ml. of dimethylsulfoxide and the resulting 2-phase solution was stirred at 100° for 16 hours. The mixture was cooled, diluted with H2O, washed with ether, acidified with 2N HCl, and extracted with ether. The ether solutions were washed with brine, dried over sodium sulfate and stripped of solvent. The residue was crystallized from ether-30°-60° petroleum ether to give (±)-6-benzyloxy-2,5,7,8-tetramethylchroman-2-carboxylic acid as a white solid, m.p. 154.5°-155°.

1. additionTo a mixture of 0.5 g
2. customto give a solution
3. additionTo this solution was added 3 ml
4. temperatureThe mixture was cooled
5. washwashed with ether
6. extractionextracted with ether
7. washThe ether solutions were washed with brine
8. dry with materialdried over sodium sulfate
9. customThe residue was crystallized from ether-30°-60° petroleum ether