NMR-spektroskopische Untersuchungen zurE/Z-Isomerie von substituierten Dithiocarbazinsäurederivaten

摘要

NMR-spectroscopic investigations of substituted dithiocarbacinic acid derivatives show the existence of configurational isomers relative to the C=N double bond, but no tautomerism. We applied chemical shift differences in the1H-,13C- and15N-NMR-spectra, N - H and C - H coupling constants and NOE difference measurements in the solvents CDCl3,DMSO-d6and partly CD3OD in order to discriminate between the isomers and to determine the configurational composition. Compounds4and5exist asE-isomers in all solvents, compounds1, 2and3as a mixture ofE/Z-isomers. InDMSO-d6theE-form is the preferred isomer.