Conversion of 2-thiohydantoins and their derivatives to the corresponding hydantoins in the processes of complexation reactions with copper(II) chloride dihydrate

The treatment of 5-pyridylmethylene-substituted 2-thiohydantoins or 2-alkylthio-3,5-dihydro-4Н-imidazole-4-ones with CuCl2.2H2O affords the mononuclear or polymeric copper(II) complexes of the corresponding hydantoins. A presumable mechanism of hydantoin moiety formation involves Lewis acid catalyzed nucleophilic substitution of a sulfur-containing leaving group in the organic ligand by a water molecule from CuCl2.2H2O. The copper complexes Cu(L1-H)Cl(H2O) (7; L1 = (Z)-3-allyl-5-(pyridine-2-ylmethylene)imidazole-2,4(4H)-dione) and Cu(L2-H)2 (9; L2 = Z)-3-allyl-5-(5′-bromo-pyridine-2-ylmethylene)imidazole-2,4(4H)-dione) were characterized by X-ray diffraction.

Graphical abstractThe treatment of 5-pyridylmethylene-substituted 2-thiohydantoins or 2-alkylthio-3,5-dihydro-4Н-imidazole-4-ones with CuCl2.2H2O affords the mononuclear or polymeric copper(II) complexes of the corresponding hydantoin anions. A presumable mechanism of hydantoin moiety formation involves Lewis acid catalyzed nucleophilic substitution of a sulfur-containing leaving group by a water molecule from CuCl2.2H2O.Figure optionsDownload full-size imageDownload as PowerPoint slide