Carbonic anhydrase inhibitors .35. Synthesis of Schiff bases derived from sulfanilamide and aromatic aldehydes: The first inhibitors with equally high affinity towards cytosolic and membrane-bound isozymes

A series of Schiff bases was prepared by reaction of sulfanilamide with substituted benzene- and heterocyclic aldehydes. The compounds were characterized by standard procedures, and were assayed as inhibitors of the zinc enzyme carbonic anhydrase (CA). The new compounds act as inhibitors towards isozymes CA I and II (cytosolic) and CA IV (membrane-bound), and possess an equally high affinity for the last two, in contrast to classical inhibitors which are 17-33 times less effective against CA IV. This is the first evidence of high-affinity CA IV inhibitors, and might lead to the development of low molecular weight CA IV isozyme-specific derivatives.