Green-Light-Sensitive BODIPY Photoprotecting Groups for Amines

Abstract

We describe a series of easily accessible, visible-light-sensitive (λ > 500 nm) BODIPY (boron-dipyrromethene)-based photoprotecting groups (PPGs) for primary and secondary amines, based on a carbamate linker. The caged compounds are stable under aqueous conditions for 24 h and can be efficiently uncaged in vitro with visible light (λ = 530 nm). These properties allow efficient photodeprotection of amines, rendering these novel PPGs potentially suitable for various applications, including the delivery of caged drugs and their remote activation.

A New Photocage Derived from Fluorene

“…were the first to report a new photocage based on visible‐light‐absorbing fluorophores . Since then, promising new PPGs have been developed based on the boron‐dipyrromethene (BODIPY) fluorophore . However, so far, BODIPY photocages are limited to the direct release of a good leaving group (LG).…”

“…[19] Since then, promising new PPGs have been developed based on the boron-dipyrromethene( BODIPY)f luorophore. [20][21][22][23][24] However,s o far,B ODIPY photocages are limited to the direct release of a good leaving group (LG). In contrast, Wang et al demonstrated the remarkable power of the simple 3-diethylaminobenzyl (1; Scheme 1) chromophoref or the release of poor LGs, such as amines [25] and alcohols.…”

Red-light-sensitive BODIPY photoprotecting groups for amines and their biological application in controlling heart rhythm

“…19,20 However, compared to one photon excitation, irradiation with higher intensity of light is usually needed as the probability of such a transition is smaller. 20,21 Facing these important challenges and limitations in designing a red-light responsive cage for amines, and inspired by the work of the group of Winter and Weinstain and our previous reports, 14,17,[22][23][24][25] describing a red-sensitive BODIPY PPG for esters, we set out to design and obtain analogous PPGs for amines applicable in biological setting. For this purpose, we choose the BODIPY (boron-dipyrromethene) core because of its: (i) easy synthesis, (ii) near-ideal photochemical properties; (iii) a narrow absorption band; and (iv) high e values (B10 5 M À1 cm À1 ).…”

“…To obtain derivatives of biologically relevant amines whose activity could be controlled by irradiation with red light, we designed a synthetic route for the preparation of BODIPY-PPG based on reactive carbamates. The synthesis of the desired compounds started with the preparation of BODIPY ester 1 as reported previously 25 (Fig. 2), followed by a Knoevenagel condensation leading to compound 2.…”

A Photocleavable Contrast Agent for Light-Responsive MRI

“…In the future, the design may set the base for agents with improved features, especially in terms of activation wavelength, uncaging efficiency and reversing the contrast agent to a “switch on” instead of “switch off” mode. Towards this end, the replacement of the NVOC-group by another photocleavable group, like a boron-dipyrromethene (BODIPY)-based one, would render the CA responsive to red or NIR-light, minimizing the harmful effects of the employed irradiation on the surrounding tissue [ 52 , 53 ]. A “switch on” MRI CA could be established by designing a molecule that bears a coordinating moiety, such as a carboxylic acid, which will be cleaved off upon irradiation.…”