Fluorescent Caged Compounds of 2,4-Dichlorophenoxyacetic Acid (2,4-D): Photorelease Technology for Controlled Release of 2,4-D

Abstract

A novel controlled-release formulation (CRF) of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) was developed to reduce its negative environmental impacts by improving its herbicidal efficacy. The 2,4-D was chemically caged by coupling with photoremovable protecting groups (PRPGs) of coumarin derivatives. Photophysical studies of caged compounds showed that they all exhibited strong fluorescence properties. Controlled release of 2,4-D was achieved by irradiating the caged compounds using UV-vis light (310, 350, and 410 nm). The effect of various factors such as pH, solvent, and different substituents at the seventh position of coumarin moiety on the rate of photorelease was studied. The herbicidal activity of caged compounds and 4-(hydroxymethyl)-7-substituted coumarins was studied against Vigna radiata . The new formulation provided greater control over the release of 2,4-D by UV-vis light and also demonstrated the potential of the PRPGs not only to act as a delivery device but also to possess herbicidal activity after photorelease.

A p‐Hydroxyphenacyl–Benzothiazole–Chlorambucil Conjugate as a Real‐Time‐Monitoring Drug‐Delivery System Assisted by Excited‐State Intramolecular Proton Transfer

“…If we could modify the pHP group to obtain a fluorescent phototrigger that can be excited at wavelengths greater than 400 nm, while maintaining its salient features, the resulting phototrigger might exhibit rapid and clean release of active molecules in the visible wavelength region with strong fluorescence. This modified pHP group might be a promising alternative to the existing o ‐nitrobenzyl, coumarylmethyl, and quinoline derivatives for the design of photoresponsive drug‐delivery systems (DDSs).…”

A p‐Hydroxyphenacyl–Benzothiazole–Chlorambucil Conjugate as a Real‐Time‐Monitoring Drug‐Delivery System Assisted by Excited‐State Intramolecular Proton Transfer

“…(a)].T he pHP group has been used extensively to cage biomolecules owing to its salient features: [6] I) rapid and clean release, II) high photochemical efficiency, III) synthetic accessibility, IV) ready installation on most substrates,a nd V) the formation of at ransparent (no inner-filter effect) biocompatible photoproduct. If we could modify the pHP group to obtain afluorescent phototrigger that can be excited at wavelengths greater than 400 nm, while maintaining its salient features,the resulting phototrigger might exhibit rapid and clean release of active molecules in the visible wavelength region with strong fluorescence.T his modified pHP group might be apromising alternative to the existing o-nitrobenzyl, [7,8] coumarylmethyl, [9] and quinoline [10] derivatives for the design of photoresponsive drug-delivery systems (DDSs). If we could modify the pHP group to obtain afluorescent phototrigger that can be excited at wavelengths greater than 400 nm, while maintaining its salient features,the resulting phototrigger might exhibit rapid and clean release of active molecules in the visible wavelength region with strong fluorescence.T his modified pHP group might be apromising alternative to the existing o-nitrobenzyl, [7,8] coumarylmethyl, [9] and quinoline [10] derivatives for the design of photoresponsive drug-delivery systems (DDSs).…”

Design and Synthesis of a Caged Carboxylic Acid with a Donor−π–Donor Coumarin Structure: One-photon and Two-photon Uncaging Reactions Using Visible and Near-Infrared Lights

“…5 The fast release of bioactive compounds (drug) from the singlet excited state, 1 [CM-drug]*, is an advantage that allows their use in physiological studies. 6,7 However, coumarins exhibit absorption wavelength in the region 280-300 nm. 8,9 UV irradiation is needed to generate the excited state using one-photon (OP) excitation, causing cell damage.…”