1H and 13C dynamic nuclear magnetic resonance study of hindered rotation in thiobenzoylpiperidines and thiobenzoylmorpholines. Correlation between barrier heights of amides and thioamides

The free energies of activation for hindered rotation around the CN bond have been determined for a series of N,N-disubstituted thioamides by means of 13 C and 1 H dynamic nmr.A comparison between barriers for 20 amides and the corresponding thioamides, studied under similar conditions, has been dra...

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Bibliographic Details
Published in:Canadian journal of chemistry 1977-07, Vol.55 (14), p.2649-2655
Main Authors: Piccinni-Leopardi, Carla, Fabre, Omer, Zimmermann, Daniel, Reisse, Jacques, Cornea, F, Fulea, C
Format: Article
Language:English
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Summary:The free energies of activation for hindered rotation around the CN bond have been determined for a series of N,N-disubstituted thioamides by means of 13 C and 1 H dynamic nmr.A comparison between barriers for 20 amides and the corresponding thioamides, studied under similar conditions, has been drawn up using both our results and data obtained from the literature. An excellent linear correlation has been obtained. The same correlation also holds for primary (thio)amides and seems to be of general significance. Substituent effects on the barrier heights of thioamides and amides are discussed in connection with some particular cases.
ISSN:0008-4042
1480-3291
DOI:10.1139/v77-369