A series of 5-substituted 3-thiophenesulfonamides was prepared from 4-bromo-2-thiophene carboxaldehyde. Several of these compounds inhibited carbonic anhydrase II in vitro at concentrations of less than 10 nM. In the ex vivo assay, these compounds have inhibitory values in the 25–81% range. Additionally, none of these compounds exhibit sensitization potential as determined by in vitro measurement of cysteine reactivity.
