Synthesis, characterization and cytotoxic activity of palladium (II) carbohydrate complexes

Abstract

Carbohydrate containing pyridyl triazole ligands, 5-deoxy-1,2-O-isopropylidene-5-(4-(2-pyridyl)-1H-1,2,3-triazole-1-yl)-α-D-xylofuranose (2a), 3-O-Benzyl-5-deoxy-1,2-O-isopropylidene-5-(4-(2-pyridyl)-1H-1,2,3-triazol-1-yl)-α-D-xylofuranose (2b), methyl-5-deoxy-2,3-O-isopropylidene-5-(4-(2-pyridyl)-1H-1,2,3-triazol-1-yl)-β-D-ribofuranoside, (2c) and 6-deoxy-1,2:3,4-di-O-isopropylidene-6-(4-(2-pyridyl)-1H-1,2,3-triazol-1-yl)-α-D-galactopyranose (2d) were prepared by the ‘click’ reaction of 2-ethynyl pyridine with the corresponding azides. The palladium complexes were synthesised by the reaction of pyridyl triazole ligands with [Pd(COD)Cl2] in dichloromethane. All the compounds were characterised by NMR, IR, mass and elemental analysis. Structural characterization of the ligand 2a was done by X-ray crystallography. The ligands and complexes were tested for their cytotoxic activity on different cell lines like A549 (human alveolar adenocarcinoma cells), Neuro2a (mouse neuroblastoma cells), HeLa (cervical carcinoma cancer cells), MDA-MB-231 (human breast adenocarcinoma cells) and MCF7 (human breast adenocarcinoma cells). The complexes showed considerable cytotoxicity while the ligands were non-toxic on the tested cell lines. Pyridyl-carbohydrate triazole ligands were prepared by means of Cu(II) catalysed 1,3-dipolar cycloaddition reaction. Palladium (II) complexes were prepared by treating these ligands with [Pd(COD)Cl2]. The ligands and their palladium complexes were studied for their cytotoxic activity.