Synthesis and exploration of 2-morpholino-4-phenylthiazol-5-yl acrylamide derivatives for their effects against carbonic anhydrase I, II, IX and XII isoforms as a non-sulfonamide class of inhibitors

Novel series of 2-morpholino-4-phenylthiazol-5-yl acrylamide derivatives (8a-s) have been synthesized and explored as a non-sulfonamide class of carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. The newly synthesized molecules were evaluated for their CA inhibitory potency against four isoforms: the cytosolic isozyme hCA I, II as well as trans-membrane tumor associated isoform hCA IX and hCA XII taking acetazolamide (AAZ) as standard drug. The results revealed that most of the compounds showed good activity against hCA II, IX, and XII whereas none of them were active against hCA I (K-i > 100 mu M). It is observed that the physiologically most important cytosolic isoform hCA II was inhibited by these molecules in the range of K-i 9.3-77.7 mu M. It is also found the both the transmembrane isoforms hCA IX and XII were also inhibited with K(i)s ranging between 54.7-96.7 mu M and 4.6-8.8 mu M, respectively. The binding modes of the active compounds within the catalytic pockets of hCA II, IX and XII were evaluated by docking studies. This new non-sulfonamide class of selective inhibitors of hCA II, IX and XII over the hCA I isoform may be used for further understanding the physiological roles of some of these isoforms in various pathologies.