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Isomeric equilibria of 1‐Methylamino‐2‐nitroethene
Author(s) -
Kozerski L.,
Krajewski P.,
Bednarek E.
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.1260330910
Subject(s) - chemistry , vicinal , coupling constant , proton , solvent , nuclear magnetic resonance spectroscopy , computational chemistry , spin (aerodynamics) , stereochemistry , crystallography , organic chemistry , thermodynamics , physics , particle physics , quantum mechanics
The solvent and concentration dependence of the isomeric equilibria of 1‐methylamino‐2‐niroethene were studied by 1 H and 13 C NMR spectroscopy. The results are used for clarification of the controversy regarding the content of the E form in CDCI 3 solution, correcting an earlier suggestion concerning the stereochemical assignments around the C‐1N bond in the E form and verification of the values of the olefinic one bond proton—carbon spin—spin coupling constants, 1 J (C,H), reported recently. An unambiguous means of assigning the stereochemistry around the C‐1N bond in the E isomer is suggested, based on using the complementary information from 3 J (C‐2,NH) and 3 J (H‐1,NH), in addition to the 3 J (Me,H‐1) vicinal coupling constant.