Complexes of ruthenium(III) with some 2-aminothiazole derivatives/synthesis, properties and pharmacological studies

Four new complexes of Ru(III) with a general formula [Ru(L)2Cl2]Cl, where L = 2-amino-4-phenylthiazole (CAS 2010-06-2), 2-amino-4-methylthiazole (CAS 1603-91-4), ethyl 2-amino-4-methyl-5-thiazolecarboxylate (CAS 7210-76-6) and ethyl 2-amino-4-phenyl-5-thiazolecarboxylate (CAS 64399-23-1), were prepared. The syntheses were carried out in polar medium and inert atmosphere at a molar ratio Ru:L = 1:2 or 1:3. The compounds obtained were characterised by IR-, 1H-NMR- 13C-NMR-, UV-VIS-, EPR spectroscopy, magnetochemical and conductivity measurements. The ligands behaved as bidental, bounding Ru(III) through the nitrogen atoms from the amino group and the heterocycle. The complex of ethyl 2-amino-4-phenyl-5-thiazolecarboxylate showed significant antileukaemic activity on various human cells (IC50 values ranging from 20 to 92 micromol/l). Toxicological studies on mice indicated that such concentrations could be reached without mortality. This compound exhibited a promising antineoplastic potential and needs further pharmacological and toxicological evaluation.