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Tautomerism in some alkyl carboxylates of amino‐substituted dihydrobenzoxazepine thiones and dihydrobenzodiazepine thiones studied by 2D NMR spectroscopy. Some stereochemical effects on 2 J (C, H) and 3 J (C, H) couplings
Author(s) -
Pihlaja Kalevi,
Simeonov Mario,
Michalik Manfred,
Peseke Klaus,
Sinnwell Volker,
Voss Jurgen
Publication year - 1992
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.1260300718
Subject(s) - tautomer , chemistry , intramolecular force , alkyl , hydrogen bond , solvent , nuclear magnetic resonance spectroscopy , medicinal chemistry , carbon 13 nmr , spectroscopy , chemical shift , solvent effects , computational chemistry , stereochemistry , molecule , organic chemistry , quantum mechanics , physics
Abstract The 1 H and 13 C NMR spectra of some alkyl carboxylates of amino‐substituted dihydrobenzoxazepine thiones and dihydrobenzodiazepine thiones were recorded in CDCI 3 , and DMSO solutions, and the complete spectral assignments performed with 1D and 2D techniques. A solvent‐dependent tautomerization was established for the oxazepine derivatives, whereas the diazepines existed in the same tautomeric form in both solvents. The tautomeric structures are stabilized by strong intramolecular hydrogen bonding. Differences in the CH couplings are related to the stereochemistry of the tautomeric structures.