Conformations, equilibrium thermodynamics and rotational barriers of secondary thiobenzanilides

Article abstract of DOI:10.1016/j.tet.2016.02.035

The article deals with conformational behaviour of 2-methoxy-2′-hydroxythiobenzanilides. The CS-NH group of these compounds preferentially adopts the Z-conformation. Entropy favours the Z-conformer over the E-conformer, whereas enthalpy slightly favours the E-conformer over the Z-conformer. The rotational barrier about the CS-NH bond was determined to be (81.5±0.4) kJ/mol. No significant rotational barrier was found on the Ar-CS and Ar-NH bonds. All experimental outcomes are compared with the results of quantum-chemical calculations.