C-13 NMR-SPECTRA OF ALL ISOMERIC METHYL HYDROXYOCTADECANOATES AND ACETOXYOCTADECANOATES - DETERMINATION OF CHEMICAL-SHIFTS BY DEUTERIUM-ISOTOPE EFFECTS

Carbon‐13 NMR spectra of the 17 isomeric methyl hydroxyoctadecanoates and the corresponding acetate derivatives have been measured and chemical shifts assigned to most carbons. Sixteen specifically deuterated hydroxy esters, and their acetates, were employed to make unambiguous assignments from the deuterium isotope effects on the spectra. When substituents are separated from the ends of the chain by 2–3 methylene groups their effects are largely additive. Long range effects of the hydroxyl group were γ, +0.01; δ, −0.09; ε, −0.11; ζ, −0.06; η, −0.05; and θ, −0.04 ppm, and of the acetate group were γ, −0.20; δ, −0.20; ε, −0.16; ζ, −0.11; η, −0.08 and θ, −0.07 ppm, showing that they extend across seven methylene groups. Copyright © 1978 Heyden & Son Ltd.