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Nitrogen‐15 coupling constants: Geminal coupling, 2 J ( 15 NH), in cis ‐ and trans ‐aldonitrones and vicinal coupling, 3 J ( 15 NH), in cis ‐and trans ‐ketimines, oxaziridines and nitrones
Author(s) -
Boyd Derek R.,
Stubbs Michael E.,
Thompson N. J.,
Yeh Herman J. C.,
Jerina Donald M.,
Wasylishen Roderick E.
Publication year - 1980
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270140620
Subject(s) - geminal , vicinal , methylamine , coupling constant , chemistry , protonation , imine , stereochemistry , crystallography , medicinal chemistry , physics , organic chemistry , particle physics , catalysis , ion
Nitrogen‐15‐hydrogen 2 J ( 15 NH), 15 N, 13 C 1 J ( 15 N 13 C) and 13 C, H 1 J ( 13 CH) coupling constants have been measured and their signs determined for cis ‐and trans ‐[9‐anthryl( 13 C)methylene]( 2 H 3 )methylamine ( 15 N)‐oxide. Values of 2 J ( 15 NH) were of similar magnitude (∼2 Hz) but were of opposite sign. The results are compared and contrasted with those reported for related imino and quaternary imino systems. Vicinal 3 J ( 15 NH) coupling constants have been measured in cis ‐ and trans ‐ 15 N ‐[1‐(α‐naphthyl)ethylidene]benzylamine and 15 N ‐[1‐( p ‐nitrophenyl)ethylidene]‐t‐butylamine and were found to be larger when the imino methyl group was cis to the nitrogen lone pair. The corresponding cis and trans ketonitrones formed by photoisomerization of the derived oxaziridines had 3 J ( 15 NH) values of c. 3.3 Hz. A study of the signs and magnitudes of observed and calculated 15 N,H coupling constants for all of the 15 N labelled imines, oxaziridines, imine N ‐oxides (nitrones) and similar model systems which were synthesized is described.