Subject: Re: CCL:rotamers in n.m.r. experiment

From: [email-masked] (Frits Daalmans (4505))
Date: Fri, 17 Mar 1995 15:45:38 +0100

I know of an NMR measurement that showed what was presumably slow exchange
in N,N-di-isopropyl benzamide. The rotation around the CONH amide bond
was so slow (at ambient temperature) that 2 different rotamers could
indeed be seen.
reference:
C. Altona, R. Francke, R. de Haan, J.H Ippel, G.J Daalmans, A.J.A Westra Hoekzema, J. van Wijk,
Mag. Res. Chem 32, p. 670-678 (1994)
title: Empirical group electronegativities for vicinal NMR proton-proton couplings
along a C-C bond: Solvent effects and reparameterization of the Haasnoot equation.

good luck,
Frits

OH: PS: the solvent was CDCl3, concentration about 5 vol. %