Valdecoxib vs. borazavaldecoxib: isoxazole BN/CC isosterism as a case study in designing and stabilizing boron heterocycles

A comprehensive study on the preparation, hydrolytic stability, and the structural and spectrophotometric properties of 1,2,4,5-oxadiazaboroles is presented by way of a comparison between the NSAID drug valdecoxib (1) and its unprecedented B–N isostere, borazavaldecoxib (2). Knowledge gained from this study was employed in the design of oxadiazaborate salts, a novel class of tetrahedral boron heterocycles displaying good stability in aqueous conditions with promising antifungal and antibacterial properties.