The compound 3b behaved as more effective inhibitor against the human cytosolic isoforms hCA I and II having Ki values (368.7 and 81.4 nM) respectively, while 3n behaved as more effective inhibitor against the membrane bound cancer related isozyme hCA IX and XII, having Ki values (41.3 and 39.1 nM) respectively. Here, CYP24A1 is linked to cancer.