ISSN:
1573-9171
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Conclusions 1. The13C NMR spectra of Δ7,8- and Δ8,9-isopimaric acids and their methyl esters as well as the 7-oxo- and 7-hydroxy-Δ8,9-methyl isopimarates and abietic acid have been studied. 2. The spin-lattice relaxation times T1 of the carbon nuclei of Δ7,8- and Δ8,9-isopimaric acids and abietic acid have been measured. The found values of T1 for the C atoms of CH and CH2 groups of the skeletal part of the studied molecules indicates a dipole-dipole mechanism for the relaxation of these molecules. 3. The relaxation times T1 of atoms C19 and C20 of the CH3 groups of the isopimaric acids show free rotation of these groups, whereas the value of the time T1 for C17H3 is lower by a factor of ∼ 2 as a result of steric hindrance to the rotation of these groups from neighboring fragments.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00961752
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