Benzenesulfonamide bearing imidazothiadiazole and thiazolotriazole scaffolds as potent tumor associated human carbonic anhydrase IX and XII inhibitors

Two series of 20 novel heterocyclic compounds, imidazothiadiazoles (3a-3j) and thiazolotriazoles (4a-4j) bearing benzenesulfonamide moiety were synthesized in order to investigate the inhibition potential of both scaffolds against four selected human carbonic anhydrase isoforms (hCA I, II, IX & XII). Against human isoform hCA I, compounds 3j, 4a-4c, and 4j showed better inhibition potential (Ki<100nM) than the standard drug acetazolamide (AZA). Against hCA II, all the compounds showed moderate inhibition with the exception of 3a which showed nearly two fold better profile compared to AZA. Against hCA IX, all the compounds showed moderate inhibitory potential than AZA, whereas against hCA XII, compounds 3a-3c showed better inhibitory potential compared to AZA.