Cationic diamineplatinum(II) complexes of nalidixic acid

Abstract

The reaction of cis-A(2)PtCl(2) with sodium nalidixate (nal) leads to the cationic platinum complexes cis-[A(2)Pt(nal)](+)X(-) (1, A(2) = ethylenediamine (en), X = Cl; 2, A(2) = (1R,2R)-diaminocyclohexane (dach), X = Cl; 3, A(2) = 1,1-bis(aminomethyl)cyclohexane (bamch), X = Cl; 4, A = cyclopropylamine (cpa), X = Cl; 5, A = ammonia, X = nal). The complexes have been characterized by elemental analysis, conductivity, spectroscopic methods and X-ray analysis. The crystal structure of 5 . 5H(2)O (space group P (1) over bar; a = 10.558(3), b = 11.351(5), c = 14.803(10) Angstrom, alpha = 110.16(5), beta = 99.73(3), gamma = 110.77(2)degrees, V = 1469(2) Angstrom(3), Z = 2, R = 0.053) discloses that one nalidixate ion is chelated to the platinum atom via its carboxylate and ring carbonyl groups whereas the other nalidixate is a counter anion. These platinum complexes are stable in water, but are changed to Me,SO adducts in dimethyl sulfoxide solution. Among the title complexes, 2 and 5 have shown good antitumor activity for further investigation.