Equilibrio conformacional de -N,N-Dimetilaminocicloexanona

AUTOR(ES)
DATA DE PUBLICAÇÃO

1987

RESUMO

The aim of the present work has been the study of the conforrnational equilibriurn of a-N,N-dimethylaminocyclohexanone(4) by Hydrogen-1 and Carbon-13 nuclear magnetic resonance spectroscopy and also the study of the N,N-dirnethylamino group s effect on the Carbon-13 chernical shifts of the cycloexanone skeletal carbons, mainly on the carbonyl and a-methine carbons. In order to reach these objectives, the a-N,N-dimethyl- aminocyclohexanone(4) and the cis-(6e) and the trans-2-N,N-di- methylamino-4-t-butylcyclohexanone(6a) have been synthesized.A literature survey on a-monsubstituted cyclohexanones conformational equilibria and Carbon-13 n.m.r. data has been included to allow any comparison with the obtained results. Hydrogen-1 nuclear magnetic resonance spectra showed this technique can not be applied to our proposed studies and the lanthanide shift reagents did not lead to any concluding results. Carbon-13 chemicals shifts assignments for the above compounds have been performed according the conventional rules and confirmed by spin-echo experiments. Eliel s method has been applied to settle the conformational equilibrium leadingto reliable. Low temperature spectra were also obtained, allowing the recording of the a-N,N -dimethylaminocyclohexanone(4) axial and equatorial confomers spectra on reaching -124°C. From the chemical shifts data and signals integration the conforms ratio was obtained and both values were in close agreement to the ones obtained at room temperature.

ASSUNTO(S)

espectroscopia de ressonancia nuclear

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