Design and synthesis of thiourea compounds that inhibit transmembrane anchored carbonic anhydrases

A library of 32 novel glycoconjugate thiourea-bridged benzene sulfonamides have been synthesized from the reaction of glycosyl isothiocyanates with a panel of simple benzene sulfonamides comprising either a free amine or hydrazide. All compounds were investigated for their ability to inhibit the enzymatic activity of five human carbonic anhydrase (hCA) isozymes: hCA I, II and membrane-associated isozymes IX, XII and XIV. A physicochemical feature of the free sugar thioureido glycoconjugates was high water solubility (>20 mg/mL), as well many of these compounds exhibited a desirable potency and CA isozyme selectivity profile. From this library several inhibitors displayed excellent potency-selectivity profiles for transmembrane anchored CAs over off-target CA I and II. These molecules provide potential dual-acting candidates for the development of inhibitors that target the extracellular CAs (IX, XII and XIV)-either directly as free sugars (membrane impermeable) or indirectly as acetylated prodrugs, becoming free sugars upon esterase hydrolysis.