Several 1, 2-benzisoxazole phosphorodiamidates have been designed as prodrugs of phosphoramide mustard requiring bioreductive activation. Enzymatic reduction of 1, 2- benziosoxazole moiety is expected to result in the formation of imine intermediate due to the cleavage of the NO bond. The imine should then be spontaneously hydrolyzed to a ketone metabolite, thereby facilitating base-catalyzed β-elimination of cytotoxic phosphoramide ...