Synthesis, X-ray structures and cytotoxic activity of platinum(II), palladium(II) and copper(II) complexes with chelating ligands

Abstract

Here we present the synthesis of the new chelating ligands 1-benzothiazol-2-yl-5-(2-hydroxyphenyl)-3-methyl-1 H-pyrazole-4-carboxylic acid methyl ester ( 2a) and 1-(6-chloropyridazin-3-yl)-5-(2-hydroxyphenyl)-3-methyl-1 H-pyrazole-4-carboxylic acid methyl ester ( 2b), obtained in the reaction of 2-methyl-4-oxo-4 H-chromene-3-carboxylic acid methyl ester ( 1) with hydrazine derivatives. These ligands 2a and 2b create solid complexes with Pt(II) ( 4a, 4b), Pd(II) ( 5a, 5b) and Cu(II) ( 6a, 7a, 8a, 8b and 9b) metal ions or can be cyclized to 1-benzothiazol-2-yl-3-methyl-1 H-chromeno[4,3- c]pyrazol-4-one ( 3a) or 1-(6-chloropyridazin-3-yl)-3-methyl-1 H-chromeno[4,3- c]pyrazol-4-one ( 3b). The crystal and molecular structures of ligand 2a, its Cu(II) complexes 6a and 7a were determined by X-ray diffraction method. Cytotoxic activity of the ligands 2a and 2b and their complexes 4a, 4b, 5a, 5a, 6a, 8a, 8b and 9b, and modulation of expression of BAX and P53 genes are also shown.