4.32 g of 12-hydroxydodecanoic acid were dissolved in 200 ml of ethyl acetate and 30 ml of water, and 5.5 g of diphenyldiazomethane were added to the resulting solution, which was then stirred at room temperature overnight. At the end of this time, about 10 ml of acetic acid was added to the resulting mixture to decompose the excess diphenyldiazomethane, after which the mixture was washed with 100 ml of water and the organic layer was separated. The organic layer was then washed twice, each time with 100 ml of a 5% w/v aqueous solution of sodium bicarbonate and with a saturated aqueous solution of sodium chloride. The washed organic layer was then dried over anhydrous magnesium sulfate and the solvent was removed by evaporation under reduced pressure, to afford 9.2 g of a thickly viscous yellow oily residue. This residue was purified by silica gel column chromatography using cyclohexane containing 10% by volume ethyl acetate as eluent, to afford 5.2 g of benzhydryl 12-hydroxydodecanoate as a thickly viscous pale yellow oily substance.
