Ethyl Acetate → (25R)-16-oxo-26-hydroxycholesterol

Participants

Reaction Steps

A solution of chromium trioxide (80 mg) in water (0.4 ml) and acetic acid (0.8 ml) is added dropwise to a solution of (25R)-16β,26-dihydroxycholesterol (2) (0.500 g), and sodium acetate (2.48 g) in glacial acetic acid (90 ml), and is stirred for 18 hours at room temperature. The excess reagent is then destroyed with methanol (15 ml), and solvent is evaporated under reduced pressure. The resulting residue is diluted with water, and extracted with methylene chloride. The organic layer is washed with 5% K2CO3 and water, dried over sodium sulfate, and evaporated under reduced pressure to yield 0.48 g of crude product. The mixture is resolved by silica flash column chromatography (hexanes:ethyl acetate) to afford 0.313 g of (25R)-16-oxo-26-hydroxycholesterol (9). M.pt. 167°-169° C.

Provenance & Evidence