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Analysis of <SUP>1</SUP>H and <SUP>13</SUP>C NMR spectra of <TOGGLE>cis</TOGGLE>- and <TOGGLE>trans</TOGGLE>-10-substituted decal-2-ones by 2D NMR techniques

Authors :
Maio, G. Di
Migneco, L. M.
Vecchi, E.
Iavarone, C.
Source :
Magnetic Resonance in Chemistry; February 2000, Vol. 38 Issue: 2 p108-114, 7p
Publication Year :
2000

Abstract

The &lt;SUP&gt;1&lt;/SUP&gt;H and &lt;SUP&gt;13&lt;/SUP&gt;C NMR chemical shift assignments of 10-substituted decal-2-ones, cis (H, CH&lt;INF&gt;3&lt;/INF&gt; and CO&lt;INF&gt;2&lt;/INF&gt;CH&lt;INF&gt;3&lt;/INF&gt;) and trans (H, CH&lt;INF&gt;3&lt;/INF&gt;, OH and CO&lt;INF&gt;2&lt;/INF&gt;C&lt;INF&gt;2&lt;/INF&gt;H&lt;INF&gt;5&lt;/INF&gt;) were based on 2D COSY and HETCOR experiments, supported by selective spin decoupling experiments. The discrimination between the cis and the trans conformations was ruled out on the basis of the J(1a,9) magnitudes related to dihedral angles (Karplus rule) and also on the &lt;SUP&gt;13&lt;/SUP&gt;C shielding values of C-4 of the cis compounds, which are much more shielded than those of the trans counterparts. The best and fastest criterion of differentiation between cis and trans conformers is the constant appearance in the &lt;SUP&gt;13&lt;/SUP&gt;C PND spectra of the cis series of some signals of broadened linewidth and low intensity, essentially C-4, C-5 and C-7, a clue to site exchange processes; the trans counterparts showed only sharp signals because of their existence as a single conformation. Copyright &#169; 2000 John Wiley &amp; Sons, Ltd.

Details

Language :
English
ISSN :
07491581 and 1097458X
Volume :
38
Issue :
2
Database :
Supplemental Index
Journal :
Magnetic Resonance in Chemistry
Publication Type :
Periodical
Accession number :
ejs422953