Acetic Acid → 24-Ketocholesterol

Participants

Reaction Steps

Fucosterol (4.1 g) was dissolved in 100 ml. of methylene chloride, and while cooling the solution with dry ice-acetone to about -20° C., the fucosterol was oxidized for 30 minutes with ozone at a rate of generation of 0.86 g/hr and in a concentration of 17.2 g/m3 (O2). After the reaction, 8 g of zinc powder and 200 ml. of acetic acid were added, and the resulting ozonide was reductively decomposed at room temperature for 24 hours. The resulting zinc acetate was separated by filtration, and washed with an aqueous solution of sodium carbonate. The methylene chloride phase separated was thoroughly washed with water, and dried with anhydrous sodium sulfate. The methylene chloride was evaporated off at reduced pressure, and the resulting white crystals were column-chromatographed using silica gel as a carrier (eluted with a benzene-n-hexane mixed solvent) to afford 2.8 g of 24-ketocholesterol in a yield of 70.3%.

Provenance & Evidence