Premium
15 N NMR studies of guanidines. II —the fused‐in guanidine unit of some oxoheterocycles: A combined 15 N NMR, 13 C NMR and IR study
Author(s) -
Bedford Geoffrey R.,
Taylor Peter J.,
Webb Graham A.
Publication year - 1995
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260330511
Subject(s) - chemistry , guanidine , nuclear magnetic resonance spectroscopy , carbon 13 nmr , conjugated system , spectroscopy , proton nmr , carbon 13 nmr satellite , nmr spectra database , fluorine 19 nmr , crystallography , stereochemistry , organic chemistry , spectral line , polymer , astronomy , physics , quantum mechanics
15 N NMR spectroscopy was used to extend previous studies, by 13 C NMR and IR spectroscopy, of fused oxoheterocycles which contain the guanidine unit. These compounds fall into three clearly definable structural types, through‐conjugated, ring‐conjugated or imide‐like, any or all of which may result from the cyclization reactions used for their synthesis. It is shown that 15 N NMR and IR criteria are of equal value in distinguishing these, whereas 13 C NMR is in general unhelpful. A qualitative correlation exists between v (CN) for the guanidine unit, and the summed 15 N NMR chemical shifts for the two π‐donor nitrogen atoms. The present observations should help to establish spectroscopic criteria for structural elucidation.