One pot synthesis of Cu(II) 2,2'-bipyridyl complexes of 5-hydroxy-hydurilic acid and alloxanic acid: synthesis, crystal structure, chemical nuclease activity and cytotoxicity.

A barbiturate derivative [1,5-dihydro-5-[5-pyrimidine-2,4(1H,3H)-dionyl]-2H-chromeno[2,3-d] pyrimidine-2,4(3H)-dione] (LH(4)) was allowed to react with 2,2'-bipyridyl-dinitrato-Copper(II)-dihydrate which provides two complexes, characterized as [Cu(bpy)(L1)]·3H(2)O (1) and [Cu(bpy)(L2)]·H(2)O (2), where bpy = 2,2'-bipyridine, L1 = 5-hydroxy-hydurilic acid and L2 = alloxanic acid. In a separate reaction of LH(4) with Cu(NO(3))(2)·H(2)O another type of complex [Cu(LH(3))(2)·(H(2)O)(2)]·4H(2)O (3) is formed. The complexes were characterized by single crystal X-ray crystallography, physicochemical and electrochemical studies. The interaction of complexes 1 and 3 with DNA was monitored using absorption and emission titrations as well as circular dichroism spectroscopy. The complexes were found to cleave supercoiled plasmid DNA to nicked circular and linear DNA. Complexes 1 and 3 were also tested against T-cell lymphoma (Dalton lymphoma DL) and showed significant cytotoxic activity with IC(50) values of ~9.0 nM and 0.6 nM.