Discovery of Imine-Modified Quinazolinyl Sulfonamides as Dual hCA IX/XII Inhibitors with Potent Antiproliferative Activity

Tumor-associated carbonic anhydrases (hCA IX and XII) drive cancer survival under hypoxia. However, developing therapeutics that avoid the ubiquitous physiological isoforms (hCA I and II) to prevent off-target liabilities remains challenging. Herein, we report the design, synthesis, and evaluation of novel 3,4-dihydroquinazoline-based benzenesulfonamides as selective hCA inhibitors. Structure–activity relationship and molecular dynamics studies demonstrated that converting primary amines to imine derivatives successfully abolished hCA I activity while retaining nanomolar potency against hCA IX and XII. Specifically, BE21349 showed high affinity for hCA IX ( K I = 61.8 nM) and hCA XII ( K I = 40.5 nM), exhibiting over 33- and 51-fold selectivity for these respective isoforms over hCA I ( K I = 2090 nM). Antiproliferative screening identified the hCA I-inactive derivatives BE21349 and BE21417 as potent multitarget agents across the NCI-60 panel. Notably, BE21417 exhibited a nearly 6-fold preference for hCA XII over hCA II, representing a promising targeted anticancer scaffold.