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13C NMR spectra of alkyl- and phenylpyrazines and their N-oxides

✍ Scribed by M. Matsuo; S. Matsumoto; T. Kurihara; Y. Akita; T. Watanabe; A. Ohta

Publisher
John Wiley and Sons
Year
1980
Tongue
English
Weight
641 KB
Volume
13
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

The ^13^C chemical shifts of 37 pyrazines, including their N‐oxides, are reported. Substituent effects of methyl, phenyl and N‐oxide groups on the chemical shifts were examined. To comprehend these effects, the chemical shifts were compared with charge densities calculated by the CNDO/2 method and a good correlation was obtained. ^13^C, ^1^H coupling constants of some pyrazines were also determined and assigned. These data enable us to assign the ^13^C NMR spectra of substituted pyrazines and to understand the effects of N‐oxidation on the pyrazine nuclei.

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