<i>cis–trans</i> Isomerism in monoalkylhydroxamic acids by ¹H, ¹³C and ¹⁵N NMR spectroscopy

Abstract

Abstract The first example of cis–trans isomerism in monoalkylhydroxamic acids, detected by 1 H, 13 C and 15 N NMR spectroscopy, is reported. The 15 N NMR spectrum of CH 3 CO 15 NHOH gave a clear assignment of the OH and NH protons of both Z and E isomers. The assignment was confirmed by 1 H and 13 C NMR spectroscopy. A rotational barrier of isomerization (Δ G c ≠) of 17.8 kcal mol −1 was calculated from the variable‐temperature 1 H NMR spectra using the method of Shanan‐Atidi and Bar‐Eli.