反应 #304176

反应方程式

cholesterol

urethane

lithium tert-butoxide

cholesterol

epibromohydrin

→

Glycidyl cholesterol

溶剂

—

hexanes

DMAc

—

KHCO3

反应条件

后处理

1. 1
   其他to slowly come to room temperature
2. 2
   其他(21-23° C.) where it
3. 3
   workup.WAITwas incubated for an additional hour
4. 4
   萃取extracted with three administrations of n-heptane
5. 5
   干燥The combined organic layers were dried over Na2SO4
6. 6
   过滤After filtration from the desiccant
7. 7
   其他the solvent was removed in vacuo
8. 8
   其他the residue was purified by flash-chromatography on silica gel employing elution with hexane, hexane/toluene (1:1 mixture), and toluene
9. 9
   workup.ADDITIONThe fractions containing pure glycidyl cholesterol
10. 10
    其他dried in vacuo until crystallization

实验过程

A schematic diagram of the reactions used for covalent binding of cholesterol to the urethane hard segments by the reaction of bromobutylated Tecothane® with 2-hydroxy-3-β-cholesteryloxypropanethiol is presented in FIGS. 1 and 2. Glycidyl cholesterol (FIG. 1) was synthesized by dissolving cholesterol in DMAc under a flow of dry argon and adding 1 M lithium tert-butoxide in hexanes. After cooling to 5° C., freshly distilled epibromohydrin was added and the mixture was stirred at 3-5° C. for 2 hours and allowed to slowly come to room temperature (21-23° C.) where it was incubated for an additional hour. The reaction mixture was diluted with 0.5% aqueous KHCO3 and extracted with three administrations of n-heptane. The combined organic layers were dried over Na2SO4. After filtration from the desiccant, the solvent was removed in vacuo and the residue was purified by flash-chromatography on silica gel employing elution with hexane, hexane/toluene (1:1 mixture), and toluene. The fractions containing pure glycidyl cholesterol were pooled and dried in vacuo until crystallization occurred. Purity was confirmed with 1H NMR (data not shown).

来源