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Solvent effects on the nuclear magnetic resonance spectra of methyl hydroxystearates
Author(s) -
Tulloch A. P.
Publication year - 1966
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02682567
Subject(s) - quinoline , chemistry , pyridine , methylene , carbon tetrachloride , solvent , spectral line , molecule , medicinal chemistry , photochemistry , organic chemistry , physics , astronomy
High resolution NMR spectra of all the isomeric methyl hydroxystearates have been measured in carbon tetrachloride, pyridine, and quinoline. As a result of association with the solvent, spectra in pyridine, and particularly in quinoline, are considerably different from those in carbon tetrachloride. The two pairs of methylene groups on either side of the CHOH grouping are deshielded by the associated solvent molecule giving a new signal at 1.58 ppm in pyridine, and at 1.75 ppm in quinoline. Deshielding of the terminal CH 3 occurs in isomers with hydroxyl near the methyl end, and of the methylene alpha to the ester group in isomers with hydroxyl near the ester end of the chain. When the spectra of isomers substituted near the center of the chain are observed in quinoline, the major methylene signal is split into two peaks due to differential shielding by the solvent. The differences between the spectra of each isomer measured in quinoline are sufficiently large for use as a method of identification.