Synthesis of new derivatized pyrazole based ligands and their catecholase activity studies

A synthesis of three new tripodal ligands: 3-[bis-(3,5-dimethyl-pyrazol-1-ylmethyl)-amino]-propan-1-ol L1, 3-[bis-(5-methyl-3-carbomethoxy-pyrazol-1-ylmethyl)-amino]-propan-1-ol, L2 and 3-[bis-(5-methyl-3-carboethoxy-pyrazol-1-ylmethyl)-amino]-propan-1-ol L3 is reported. The in situ-generated copper(II) complexes of three new compounds (L1–L3) were examined for their catalytic activities and were found to catalyse the oxidation reaction of catechol to o-quinone with the atmospheric dioxygen. These activities depend on the nature of the ligand and the copper salts.