Proton tautomerism in 5-dimethylaminomethylidene-4-(o-,m-,p-hydroxyphenyl)amino-1,3-thiazol-2(5H)-ones: synthesis, crystal structure and spectroscopic studies

Three new 5-dimethylaminomethylidene-4-phenylamino-1,3-thiazol-2(5H)-ones with an hydroxyl group in the ortho, meta and para positions on the phenyl ring were synthesized in order to deduce the structural changes occurring on prototropic tautomerism of the amidine system. The existence of all the title compounds solely in the amino tautomeric form has been established in the solid and liquid (dimethyl sulfoxide solution) phases. The title compounds are analyzed from the point of view of the electronic effects and conformational freedom of their molecules. The intermolecular interactions in the crystals and their supramolecular architecture are highlighted.

Automated summary

Three new derivatives of 5-dimethylaminomethylidene-4-phenylamino-1,3-thiazol-2(5H)-one were synthesized and their prototropic tautomerism was studied. The compounds were found to exist solely in the amino tautomeric form in both solid and liquid phases. The electronic effects, molecular conformation, and intermolecular interactions in the crystals were analyzed.