反应详情

Pyridine-sulfur trioxide (5.0 g) was added to 5α-cholest-8(14)-en-3β-ol-15-one (2.0 g; 5.0 mmol) in dry chloroform (50 ml; ethanol-free; dried over Linde molecular sieve, type 3A). The resulting mixture was stirred at room temperature for 3 hours. The excess reagent was removed by filtration, washed with a small volume of chloroform, and the filtrate was cooled to -40° C. in a dry ice-acetone bath and filtered through Hyflo Super-Cel (Johns-Manville Corp.). Hexane was added to the chloroform filtrate until a cloudiness appeared whereupon cooling to 0° C. gave a white precipitate. This material was collected by filtration and placed in a vacuum desiccator for 100 hours at room temperature to remove all traces of solvent. The product, 5α-cholest-8(14)-en-15-one-3β-yl pyridinium sulfate (2.4 g; 86% yield), had the following structural formula as confirmed by i.r., n.m.r., and m.s. analyses: ##STR55##

1. customThe excess reagent was removed by filtration
2. washwashed with a small volume of chloroform
3. temperaturethe filtrate was cooled to -40° C. in a dry ice-acetone bath
4. filtrationfiltered through Hyflo Super-Cel (Johns-Manville Corp.)
5. additionHexane was added to the chloroform filtrate until a cloudiness
6. temperaturewhereupon cooling to 0° C.
7. customgave a white precipitate
8. filtrationThis material was collected by filtration
9. waitplaced in a vacuum desiccator for 100 hours at room temperature
10. customto remove all traces of solvent