Carbonic anhydrase inhibitors. Part 55. Metal complexes of 1,3,4-thiadiazole-2-sulfonamide derivatives: In vitro inhibition studies with carbonic anhydrase isozymes I, II and IV

Coordination compounds of 5-chloroacetamido-1,3,4-thiadiazole-2-sulfonamide (Hcaz) with V(IV), Cr(III), Fe(II), Co(II), Ni(II) and Cu(II) have been prepared and characterized by standard procedures (spectroscopic, magnetic, EPR, thermogravimetric and conductimetric measurements). Some of these compounds showed very good in vitro inhibitory properties against three physiologically relevant carbonic anhydrase (CA) isozymes, i.e., CA I, II, and IV. The differences between these isozymes in susceptibility to inhibition by these metal complexes is discussed in relationship to the characteristic features of their active sites, and is rationalized in terms useful for developing isozyme-specific CA inhibitors.