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Carbon-13 NMR spectra of monosubstituted pyrazines

✍ Scribed by C. J. Turner; G. W. H. Cheeseman

Publisher
John Wiley and Sons
Year
1974
Tongue
English
Weight
376 KB
Volume
6
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

Carbon‐13 NMR chemical shifts and one‐bond carbon–hydrogen coupling constants have been obtained at 15·09 MHz. The trends in the carbon chemical shifts obtained for the pyrazines parallel those of monosubstituted benzenes and 2‐substituted pyridines, except for the direct effect of substitution where the pyrazines resemble pyridines not benzenes. The substituent effects on the ^13^C NMR spectra are generally quite similar to those in the ^1^H NMR spectra. The ^13^C NMR spectrum of the tautomeric hydroxypyrazine has been compared with the ^13^C NMR spectra of 2‐, 3‐ and 4‐hydroxypyridines. Hydroxy compounds that can exist as a cyclic amide show a large meta substituent effect on the chemical carbon shift.

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