Carbamic acid, ethyl ester → Glycidyl cholesterol

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Reaktionsschritte

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).

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