Hydrogen peroxide (0.35 ml.; 30% aqueous) is added to a solution of PGA2 (200 mg.) in 5 ml. of methanol. The mixture is cooled to -20° C., and 0.75 ml. of one N aqueous sodium hydroxide solution is slowly added with stirring. Atter 1 hour of stirring at -20° C., 1 ml. of one N hydrochloric acid is added, and the mixture is evaporated under reduced pressure. The residue is dissolved in ethyl acetate, and the resulting solution is washed successively with water and brine, dried with anhydrous sodium sulfate, and evaporated. The residue is treated with amalgamated aluminum as described in Example 8, using 2.5 ml. diethyl ether, 0.25 ml. methanol, and 0.03 ml. water, the amalgamated aluminum being added in 2 portions. When the reduction is complete, ethyl acetate and one N hydrochloric acid are added to the reaction mixture and the mixture is separated in a separatory funnel. The ethyl acetate layer is washed successively with one N hydrochloric acid, water, and brine, dried with anhydrous sodium sulfate, and evaporated. The residue is subjected to preparative thin layer chromatography to give PGE2 and 11β-PGE2 in the ratio 1:2.
