Copper(II) complexes of a nonsteroidal anti-inflammatory drug niflumic acid. Synthesis, crystal structure of tetrakis-μ-(2-[3-(trifluoromethyl)phenyl]aminonicotinato)bis(dimethylsulfoxide)dicopper(II) complex at 190 K. Anti-inflammatory properties

Abstract

The synthesis and characterization of three complexes with a potent nonsteroidal anti-inflammatory drug niflumic acid {2-[3-(trifluoromethyl)phenyl]aminonicotinic acid} with formula [Cu(niflumato) 2L] (L=H 2O, DMSO=dimethylsulfoxide, DMF= N, N-dimethylformamide) were investigated. The crystal and molecular structure of the {Cu(niflumato) 2(DMSO)} 2 was reported. Crystallographic data are as follows: monoclinic system, space group P2 1/ n, Z=2, a=11.1318(8), b=17.513(2), c=15.336(1) Å, β=103.316(8)°, V=2909.4(4) Å 3. The structure was refined to R=0.030 and w R=0.037 for 3702 reflections with I> σ( I). It consists of centrosymmetric binuclear units with the Cu–Cu i (symmetry code i: 1− x, − y, 1− z) distance between two centrosymmetrically related ions of 2.6272(5) Å. Each Cu(II) ion in [Cu 2(DMSO) 2(μ-niflumato) 4] is coordinated to an apical dimethylsulfoxide O atom on the one hand and to the equatorial carbonyl and carboxylic O atoms of two crystallographically independent niflumate moieties and their centrosymmetric counterparts on the other hand. In spite of the low-temperature (190 K) crystal measurements, one –CF 3 grouping exhibits some disorder. The biological activities of these complexes were compared to that of niflumic acid. Niflumic acid and its various copper complexes significantly inhibited polymorphonuclear leukocyte (PMNL) oxidative metabolism, as assessed by chemiluminescence and O − 2 generation measurement. This effect was dose-dependent. All copper complexes exerted a similar inhibiting effect which was always significantly higher than that exerted by the parent drug.