p-Toluenesulfonic acid → 3beta-Acetoxy-1alpha,2alpha-epoxy-7alpha-hydroxypregn-5-ene-20-carbaldehyde

Participants

Reaction Steps

In 4 ml of acetone was dissolved 4.9 mg (0.01 mmole) of 20-(5,5-dimethyl-1,3-dioxan-2-yl)-1α,2α-epoxy-7α-hydroxypregna-5-en-3β-yl acetate, followed by addition of 1 ml of a 1 mmol/1 solution of p-toluenesulfonic acid in acetone (containing 0.001 mmole of p-toluenesulfonic acid). The mixture was stirred at room temperature for 12 hours. From the reaction mixture thus obtained, the solvent was distilled off under reduced pressure and the residue was diluted with methylene chloride. This methylene chloride solution was washed successively with saturated aqueous sodium hydrogen carbonate solution and saturated aqueous sodium chloride solution and dried over magnesium sulfate. The solvent was then distilled off under reduced pressure and the residue was purified by silica gel chromatography (eluent:ethyl acetate-hexane =1:5, v/v) to recover 2.7 mg of 3β-acetoxy-1α,2α-epoxy-7α-hydroxypregna-5-ene-20-carbaldehyde (yield: 67%).

Provenance & Evidence