Long conjugated 2-nitrobenzyl derivative caged anticancer prodrugs with visible light regulated release: preparation and functionalizationsElectronic supplementary information (ESI) available: Detailed synthesis procedures and characterizations for the intermediate compounds, UV-vis and HPLC spectra for the final new prodrugs. See DOI: 10.1039/c2ob25701g

A series of anticancer prodrugs with different chemical functional groups were prepared, in which the styryl conjugated 2-nitrobenzyl derivatives were introduced as the phototrigger to regulate the drug (chlorambucil) release. Compared to the common 4,5-dimethoxy-2-nitrobenzyl caged compounds, most of the prodrugs exhibited large and redshifted one-photon absorption within the visible range. One-photon excitation for the drug release was studied by measuring UV-vis absorption, FT-IR, and HPLC spectra, which suggested that chlorambucil was released effectively and precisely by manipulating external light conditions. And the introduction of different functional groups made this type of prodrug a good platform to further react with some typical drug carriers and to further form excellent visible light responsive drug delivery systems. Moreover, the drug also could be effectively released under the excitation of two-photon at 800 nm with comparable photorelease efficiencies. Photoactivated anticancer prodrugs with different functional linkages were synthesized and used as a new strategy for photo-controlled release systems.