2,3-Erythro-dihydroxyhexacosanoic acid and homologs: isolation from yeast cerebrin phosphate and determination of their structures.

Homologs of methyl esters of very polar fatty acids were obtained by methanolysis of cerebrin phosphate isolated from baker's yeast. The major ester component was isolated by preparative gas-liquid chromatography and was found to be 2,3-dihydroxyhexacosanoic acid as deduced from the mass spectra of its trimethylsilyl ether and isopropylidene derivative, reaction with periodate, and comparison of its chromatographic behavior with that of synthetic erythro- and threo-dihydroxy acids. Its infrared spectrum supported the above conclusions. From their retention times by gas-liquid chromatography, the homologs were found to be saturated, unbranched 2,3-dihydroxy fatty acids with 24-27 carbon atoms. The synthesis of the new fatty acids, erythro- and threo-2,3-dihydroxyhexacosanoic acids, is also reported. A method for separating trans-2-hexacosenoic acid, a key intermediate of the above synthesis, and its isomer, trans-3-hexacosenoic acid, both formed by dehydrobromination of 2-bromohexacosanoic acid, is also described.