A 15N nuclear magnetic resonance study of the base-catalyzed NH2 exchange reactions of acetamide and thioacetamide

The base-catalyzed ? NH₂ exchange reactions of acetamide and thioacetamide were studied by ¹⁵N nuclear magnetic resonance spectroscopy by the use of line-shape analysis. The ¹⁵N NMR spectra of these primary amides at intermediate exchange rates were broad doublets, which indicated that the two amide protons were exchanging at different rates. The line-shape analysis indicated that the ratio of exchange rates was 6±1 for acetamide and 3±1 for thioacetamide.