Abstract
Thioxo-thioenol tautomerism was discussed in ethyl β-mercaptothiocinnamate and β-mercaptocinnamamides, in connection with their chelating abilities, through the ultraviolet absorption spectra in various solvents, and the estimation of the thioenol by the iodometry. Ethylβ-mercaptothiocinnamate and N-phenyl-β-mercaptocinnamamide were confirmed to be present mainly as the cis-thioenol form, and the equilibrium should be considered only between th thioxo and the cis-thioenol forms. On the contrary, in N-ethyl-β-mercaptocinnamamide, the trans-thioenol form should be taken into consideration in its thioxothioenol tautomerism.
