2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → Cholesta-1,4,6-triene-3,24-dione

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Reaction Steps

Fucosterol is oxidized with ozone at low temperatures, and the resulting ozonide is reduced with an acetic acid/zinc system to form 24-ketocholesterol of the following formula ##STR15## in a yield of about 60 to 75%. The resulting 24-ketocholesterol is oxidized, for example, with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) under reflux of, for example, dioxane to form cholesta-1,4,6-triene-3,24-dione of the following formula ##STR16## and then this oxidation product is epoxidized at room temperature under alkaline conditions (pH about 7.5-9) using hydrogen peroxide, for example.

Provenance & Evidence