Carbonic anhydrase inhibitors: inhibition of cytosolic carbonic anhydrase isozymes II and VII with simple aromatic sulfonamides and some azo dyes.

Several substituted benzenesulfonamides were synthesized by various pathways starting from sulfanilamide. The sulfanilamide diazonium salt was reacted with copper (I) halides, potassium iodide and/or aromatic derivatives, leading to 4-halogeno-, and 4-hydroxy-benzenesulfonamides as well as diazo dyes incorporating sulfamoyl moieties. These sulfonamides were assayed as inhibitors of two physiologically relevant isoforms of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), i.e., the cytosolic CA II (ubiquitous), and CA VII (brain-specific enzyme). Good CA inhibitory activity was detected for some of these derivatives, with inhibition constants (Ki) in the range of 17.5-863 nm against CA II; and 30-4200 nm against CA VII.