E-Z-izomerization of 2-methylenethiazolidin-4-ones
Morzherin, YY × Kosterina, MF Berseneva, VS Dehaen, Wim Bakulev, VA #
Russian chemical bulletin vol:51 issue:7 pages:1292-1297
The equilibrium concentrations of E- and Z-isomers of thiazolidin-4-ones containing exocyclic double bonds in positions 2 and 5 of the cycle were determined in DMSO-d(6). The influence of the nature of the substituents on the equilibrium position was found. Electron-releasing substituents stabilize the E, Z-configuration and electron-withdrawing substituents stabilize the Z,Z-configuration. The association constants of E- and Z-2-ethoxycarbonyl-methylenethiazolidin-4-ones with the sodium cation were determined by H-1 NMR spectroscopy.