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Carbon‐13 NMR spectra of all the isomeric methyl hydroxy‐ and acetoxyoctadecanoates. Determination of chemical shifts by deuterium isotope effects
Author(s) -
Tulloch A. P.
Publication year - 1978
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270110302
Subject(s) - methylene , deuterium , chemistry , chemical shift , nmr spectra database , deuterium nmr , spectral line , kinetic isotope effect , methyl group , carbon 13 nmr , medicinal chemistry , carbon fibers , isotope , organic chemistry , group (periodic table) , materials science , physics , quantum mechanics , astronomy , composite number , composite material
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.