Acetic Acid → 11-Oxo-15,20-cycloprosta-8(12),13,15,17,19-pentaen-1-oic acid

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Reaction Steps

6 Parts of 3-hydroxy-5-oxo-2-styrylcyclopent-1-eneheptanoic acid is dissolved in 71 parts of ethanol and cooled to about 10° as 1.88 parts of triethylamine is added. The solution is stirred as 1.5 parts of sodium borohydride dissolved in 100 parts of water is added dropwise at 10°-15°. After stirring at about 15° for 4 hours, the mixture is acidified with dilute aqueous acetic acid and the oily precipitate is extracted with ethyl acetate. The organic solution is washed with dilute aqueous sodium chloride solution, dried over anhydrous sodium sulfate and concentrated to an orange oil. Then the oil is taken up in benzene and chromatographed on silicic acid as the column is eluted with benzene containing increasing amounts of ethyl acetate. A fraction eluted with 30% ethyl acetate is crystallized from ethyl acetate-hexane to give pale yellow crystals of 3-oxo-2-styrylcyclopent-1-eneheptanoic acid, melting at about 118°-120°. That compound displays, in chloroform, absorption peaks in the infrared spectrum at about 2940 and 1700 reciprocal centimeters and an absorption band, in methanol, in the ultraviolet spectrum at about 288 millimicrons with a molecular extinction coefficient of about 24,400. That compound is represented by the following structural formula ##SPC18##

Provenance & Evidence