QUANTUM-CHEMICAL INVESTIGATION OF KETO–ENOL–ENETHIOL TAUTOMERISM IN 3-OXO-3-R1-N-R2-PROPANETHIOAMIDES

The keto–enol–enethiol tautomerism in 3-oxo-3-R^1-N-R^2-propanethioamides under vacuum and in acetone was studied in terms of density functional theory. It was established that the equilibrium depends on the structure of the 3-oxo-3-R^1-N-R^2-propanethioamides and on the nature of the solvent, but the most stable form is as a rule the keto form stabilized by an intramolecular hydrogen bond.