From classical to supramolecular dynamic stereochemistry: Double crystallization-induced diastereomerization of thiazine sulfonamide.

The interrelation between the configurational lability of nitrogen and sulfur atoms within the -NH-SO2 group of some thiazine sulfonamides is discussed. We have found that the compounds of the above series can crystallize as various diastereomers by the nitrogen atom, the relative configuration of the nitrogen atom determining the relative supramolecular configuration of the newly formed chiral sulfur atom. The paper presents a stereochemical transformation, which we have called "double crystallization-induced diastereomerization."