Nitrobenzyl-Based Photosensitive Phosphoramide Mustards: Synthesis and Photochemical Properties of Potential Prodrugs for Cancer Therapy.

Several nitrobenzyl-based photosensitive phosphoramide mustards were synthesized. The nitrobenzyl moiety was structurally varied to find the most promising prodrug candidates in respect to photorelease and activity of the alkylating species. The synthesis of these compounds proved to be applicable even in regard to compounds with additional functionalization. The target molecules 13a,b to 14 exhibited the expected red shift in their absorption spectra maximum compared to the parent nitrobenzyl moiety. As seen by UV and (31)P NMR spectroscopy, the phosphoramide mustard was quickly liberated upon irradiation with mercury arc lamps. Assaying the structurally different prodrugs on their alkylating activity showed that compounds 13b and 14, derived from secondary benzyl alcohols, are promising prodrug candidates. Their water solubility and the possibility of attaching macromolecules are encouraging vis-à-vis future investigations on their in vitro cytotoxicity.