反应详情

The whole of this benzhydryl 12-hydroxydodecanoate was dissolved in 400 ml of anhydrous ethyl acetate, and 13.7 ml of pyridine were added to the resulting solution, whilst ice-cooling, after which 3.48 g of trichloroethoxycarbonyl chloride dissolved in 10 ml of ethyl acetate were added dropwise over about 15 minutes. Insoluble salts were precipitated, after which the temperature of the mixture was allowed to return to room temperature, and the mixture was then stirred for a further 2 hours. The reaction mixture was then washed with 200 ml of 0.5N aqueous hydrochloric acid, after which it was washed with 100 ml each of a saturated aqueous solution of sodium chloride and of a 5% w/v aqueous solution of sodium bicarbonate. The organic layer was then dried over anhydrous magnesium sulfate, after which the solvent was removed by evaporation under reduced pressure. The residue thus obtained was purified by silica gel column chromatography using cyclohexane containing 20% by volume ethyl acetate as eluent, to afford a colorless and transparent viscous oil. The whole of this oil was dissolved in 5 ml of anisole, and 20 ml of trifluoroacetic acid was added to the resulting solution, whilst ice-cooling. The mixture was then left to stand for 1 hour. At the end of this time, the solvent was removed by evaporation under reduced pressure. This evaporating operation was repeated three times by adding 30 ml of toluene and dissolving the residue in 100 ml of a mixture of ethyl acetate and water. After this, 100 ml of a saturated aqueous solution of sodium bicarbonate was added to the organic layer, which emulsified the resulting mixture, and then the pH of the mixture was adjusted to a value of about 1 by the addition of concentrated hydrochloric acid. After the organic layer had been separated, it was washed with 100 ml of a saturated aqueous solution of sodium chloride and dried over anhydrous magnesium sulfate. The solvent was then removed by evaporation under reduced pressure, to afford an oily residue. The residue was purified by silica gel column chromatography using a 2:1 by volume mixture of cyclohexane and ethyl acetate as eluent and then recrystallized from hexane to afford 3.96 g of the title compound as white plate-like crystals, melting at 44.6° to 46.4° C.

1. temperaturecooling
2. additionwere added dropwise over about 15 minutes
3. customInsoluble salts were precipitated
4. customto return to room temperature
5. washThe reaction mixture was then washed with 200 ml of 0.5N aqueous hydrochloric acid
6. washafter which it was washed with 100 ml each of a saturated aqueous solution of sodium chloride and of a 5% w/v aqueous solution of sodium bicarbonate
7. dry with materialThe organic layer was then dried over anhydrous magnesium sulfate
8. customafter which the solvent was removed by evaporation under reduced pressure
9. customThe residue thus obtained
10. customwas purified by silica gel column chromatography
11. customto afford a colorless and transparent viscous oil
12. temperaturecooling
13. waitThe mixture was then left
14. waitto stand for 1 hour
15. customAt the end of this time, the solvent was removed by evaporation under reduced pressure
16. additionby adding 30 ml of toluene
17. dissolutiondissolving the residue in 100 ml of a mixture of ethyl acetate and water
18. additionAfter this, 100 ml of a saturated aqueous solution of sodium bicarbonate was added to the organic layer, which
19. additionthe pH of the mixture was adjusted to a value of about 1 by the addition of concentrated hydrochloric acid
20. customAfter the organic layer had been separated
21. washit was washed with 100 ml of a saturated aqueous solution of sodium chloride
22. dry with materialdried over anhydrous magnesium sulfate
23. customThe solvent was then removed by evaporation under reduced pressure
24. customto afford an oily residue
25. customThe residue was purified by silica gel column chromatography
26. additionby volume mixture of cyclohexane and ethyl acetate as eluent
27. customrecrystallized from hexane