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Natural abundance one-bond 13C13C coupling constants and unambiguous assignments of 13C NMR chemical shifts of dithieno[b,d]pyridines; a multivariate data analysis

✍ Scribed by Salo Gronowitz; Anna-Britta Hörnfeldt; Youhua Yang; Ulf Edlund; Bertil Eliasson; Dan Johnels

Publisher
John Wiley and Sons
Year
1990
Tongue
English
Weight
654 KB
Volume
28
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

The one‐bond ^13^C^13^C coupling constants (^1^__J__CC) in all nine possible dithieno[b,d]pyridines were measured at natural isotope abundance by using the INADEQUATE pulse sequence technique. The unambiguous assignments of the ^13^C NMR shifts of these compounds are also reported. Assignments are based on proton decoupled ^13^C spectra, heteronuclear correlation spectra (HETCOR) and 1D‐INADEQUATE ^13^C NMR spectroscopy. The effect of the fusion pattern and the influence of the heteroatoms in the ring skeleton on the NMR parameters are discussed. By a multivariate principal components data analysis, it was shown that the magnitude of ^1^J(CC) of the pyridine subunit could be satisfactorily predicted from shift data, the azomethine CH coupling constant and MNDO bond orders. The last parameter gave only a minor contribution to the coupling variability.

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