Oxalic Acid → (4E,13E)-(6RS,9alpha,11alpha,15S)-6,9-Epoxy-11,15-bis(tetrahydropyran-2-yloxy)prosta-4,13-dienoic acid

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Reaction Steps

To a solution of 480 mg of (4E,13E)-(6RS,9α,11α,15S)-6,9-epoxy-11,15-bis(tetrahydropyran-2-yloxy)prosta-4,13-dienoic acid methyl ester (prepared as described in Example 7) in 3 ml of methanol was added 5 ml of a 5% aqueous solution of potassium hydroxide at 45° to 50° C., and the mixture was stirred for one hour at the same temperature. The reaction mixture was then acidified to pH 5 to 6 with an aqueous solution of oxalic acid and extracted with ethyl acetate. The extract was washed with water and an aqueous solution of sodium chloride, dried over magnesium sulphate and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel using a mixture of cyclohexane and ethanol (20:1) as eluent to give 460 mg of the title compound having the following physical characteristics:

Provenance & Evidence