Determination of the barrier to CN bond rotation in captopril: Application of reference deconvolution to line-shape analysis

✍ Scribed by Darren V. S. Green; Ian H. Hillier; Gareth A. Morris; Lesley Whalley

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 328 KB
• Volume: 28
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260280916

✦ Synopsis

Abstract

^13^C NMR was used to study the cis‐trans isomerization of 1‐[(2__S__)‐3‐mercapto‐2‐methyl‐1‐oxopropyl]‐L‐proline (captopril) in D~2~O solution over the temperature range 50–100°C. Measurements of the rate of cis‐trans interconversion were made by line‐shape analysis and saturation transfer techniques. The combined results yielded a value for the activation energy of 89 ± 2 kJ mol^−1^ (21.3 ± 0.5 kcal mol^−1^) for the C‐N bond rotation. For line‐shape analysis the experimental data were treated by reference deconvolution, using a small amount of labelled acetonitrile as reference, before processing. It was found that the deconvolution process significantly improved the reliability of the analysis.