Determination of Kinetic Parameters of Enantiomerization of Benzothiadiazines by DCXplorer.

Benzothiadiazines differently substituted at the sulfonamidic nitrogen atom, at the stereogenic carbon atom and at the anilinic nitrogen atom have been synthesized and fully characterized. Enantioseparation of these compounds has revealed rapid on-column enantiomerization. The recently developed software DCXplorer has been successfully applied to calculate enantiomerization kinetic parameters. Enantiomerization barriers of 3-phenyl substituted benzothiadiazines, calculated in this work, have indicated a higher enantiomerization rate suggesting that the aromatic substituent exerts a strong effect on the enantiomerization process. Methyl substitution on N2 position led to higher free energy barriers of enantiomerization, suggesting negative influence of methyl in the N2 position on enantiomerization kinetics. However, methylation on N4 position increases the enantiomerization rates significantly. The results obtained have been employed to postulate an enantiomerization mechanism for chiral benzothiadiazine type compounds.