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Application of 1 H and 13 C NMR to the structural elucidation of tetrahydroquinoxalines condensed with five‐membered heterocycles
Author(s) -
Charushin V. N.,
Chernyshev A. I.,
Sorokin N. N.,
Chupakhin O. N.
Publication year - 1984
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.1270221209
Subject(s) - ring (chemistry) , vicinal , chemical shift , chemistry , coupling constant , pyrrole , furan , imidazole , crystallography , hydrogen bond , thiazole , carbon 13 nmr , stereochemistry , computational chemistry , molecule , physics , organic chemistry , particle physics
1 H and 13 C NMR spectral data for 21 N ‐methyltetrahydroquinoxalines annelated with furan, pyrrole, imidazole or thiazole rings are reported. Unambiguous assignments of the ring junction 13 C resonances were made on the basis of selective decoupling experiments and with the aid of one‐bond and long‐range 13 C– 1 H coupling constants. The effects of five‐membered heterocycles on the 1 H and 13 C chemical shifts of the ring junction hydrogen and carbon atoms are considered. Values of one‐bond 1 J (CH) and vicinal 3 J (HH) coupling constants between the ring junction protons are also discussed as a diagnostic means for structural elucidation of tetrahydroquinoxalines condensed with five‐membered heterocycles.