Sodium borohydride (1.25 molar equivalents) is added in small portions over 1/2 hour to a stirred solution of 7-[2-(3-oxo-5-phenyl-1-trans-pentenyl)-4-oxo-3-thiazolidinyl]heptanoic acid (1 molar equivalent) in ethanol maintained at 0° to 5° C. Upon completing the hydride addition, the reaction mixture is stirred at 0° to 5° for 1/2 hour, then at ambient temperature for 21/2 hours. The resulting reaction mixture is cooled to 0° to 5° C., diluted with ice water and cautiously acidified to Congo Red with 2 N hydrochloric acid providing a turbid aqueous mixture which is extracted several times with ether. The combined organic extract is dried over sodium sulfate and filtered. In vacuo evaporation of the filtrate at 40° to 50° C. leaves an oily residue which is purified by chromatography on silica gel providing the title compound as a viscous, pale yellow oil.
