70924-77-5Relevant articles and documents
Stereochemical studies of 1,2-Di(thio)acetamido-cyclohexanes and their N,N′-dimethyl derivatives by NMR and CD spectroscopy and by molecular mechanics calculations
Khan, Agha Zul-Qarnain,Ivanova, Galya I.,Spassov, Stefan L.,Sandstroem, Jan
, p. 938 - 951 (2007/10/03)
The configurations and conformations of cis- and trans- 1,2-di (thio)acetamidocyclohexane and their N,N′-dimethyl derivatives have been studied by 1H and 13C NMR spectroscopy, using chemical shifts and coupling constants, difference NOE 1H NMR spectra and 2D 1H-13C NMR correlation spectra. For the trans compounds, the Z,Z configuration of the (thio)amide groups with equatorial (thio)acetamido groups was found to be strongly preferred. For the cis compounds, E,Z configurations of the (thio)amide groups with axial E and equatorial Z groups were found to be preferred. Empirical force-field calculations with the MM2(91) force field led to predictions for the most stable configurations and conformations, mostly in very good agreement with those obtained by NMR spectroscopy. CD spectra recorded for the trans-(R,R)-N-methyl compounds in acetonitrile solution agreed well with those calculated on the basis of geometries from force-field calculations. The CD spectra calculated for the trans-(R,R)-NH- compounds and for the cis-monothio compounds showed poor agreement with the experimental spectra. Acta Chemica Scandinavica 1996.
