Determination of the threo- and erythro- configurations of vicinal diastereomeric derivatives of higher fatty acids with the aid of PMR spectra

Conclusions The PMR spectra of vicinal diastereomeric dihydroxy-, acetoxyhydroxy-, and halohydroxyoctadecanoic and -docosanoic acids and their trimethylsilyl derivatives have been considered. It has been shown that the signals of the methine protons of the erythro isomers appear at lower fields than those of the threo isomers. On passing from the dihydroxy, acetoxyhydroxy, and halohydroxy acids to their TMS derivatives, the signal of the methine proton shifts down-field, and = CHOSi (CH₃)₃ — CHOH is greater for the threo form than for the erythro form, The difference in the chemical shifts of the vicinal methine protons of the dihydroxy, acetoxyhydroxy, and halohydroxy acids and their TMS derivatives can be used to determine the threo and erythro configurations of the corresponding diastereometric derivatives of higher fatty acids.A. A. Zhdanov Leningrad State University. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 299–305, May–June, 1978.