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1 H and 13 C NMR spectra of ( Z )‐ N ‐(o‐hydroxy‐benzylidene)‐p‐x‐phenylamine N ‐oxides and ( Z )‐ N ‐(2‐hydroxy‐1‐naphthylmethylene)‐p‐X‐phenylamine N ‐oxides
Author(s) -
Arumugam N.,
Manisankar P.,
Sivasubramanian S.,
Wilson D. A.
Publication year - 1985
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.1260230407
Subject(s) - nitrone , chemistry , chemical shift , intramolecular force , aryl , hydrogen bond , substituent , ring (chemistry) , proton nmr , stereochemistry , crystallography , naphthalene , carbon 13 nmr , medicinal chemistry , molecule , organic chemistry , cycloaddition , alkyl , catalysis
Substituent effects on the 1 H and 13 C chemical shifts of ( Z )‐ N ‐(o‐hydroxybenzylidene)‐p‐X‐phenylamine N ‐oxides [( Z )‐α‐(o‐hydroxyphenyl)‐ N ‐p‐X‐phenyl nitrones] and ( Z )‐ N ‐(2‐hydroxy‐1‐naphthylmethylene)‐p‐X‐phenylamine N ‐oxides [(Z)‐α‐(2‐hydroxy‐1‐naphthyl)‐ N ‐p‐X‐phenyl nitrones] have been obtained. A combination of SFDOR and NOE methods was necessary for complete assignment of signals in the naphthalene series. Correlations have been found between the chemical shifts of various protons and carbons and Hammett o‐ parameters and Swain and Lupton F and R parameters. With both series of compounds a fixed conformation, due to intramolecular hydrogen bonding, is observed which affects the polarity of the nitrone group compared with that in α,N‐diphenyl nitrone. Reduced through‐resonance between aryl rings via the nitrone function was found. This may be attributed to the α‐aryl ring and the nitrone group being held out of coplanarity by the hydrogen bond.