A Natural Alkaloid, β-Carboline, as a One- and Two-Photon Responsive Fluorescent Photoremovable Protecting Group: Sequential Release of the Same or Different Carboxylic Acids

Abstract

The β-carboline moiety, substituted at the C1 and C3 benzylic positions with a leaving group, has been demonstrated for the first time as a photoremovable protecting group for time-dependent sequential release of two (same or different) carboxylic acids upon one- and two-photon light irradiation. Density functional theory calculations suggest that the electronic environment of the β-carboline moiety at C1 and C3 positions plays a key role in the rate of photorelease.

Visible Light-Responsive Delivery of Two Anticancer Drugs Using Single-Component Fluorescent Organic Nanoparticles

“…Based on the photochemical studies and earlier literature reports, , we have suggested a possible mechanism for the photolysis of acridine caged ester 3a in Scheme . Initially, 3a gets excited to the singlet excited state (S 1 ) ( 1 [ 3a ]*), which then undergoes a heterolytic C–O bond cleavage at the benzylic position at either C4 or C5 to produce an ion pair.…”

Wavelength-Selective Uncaging of Two Different Photoresponsive Groups on One Effector Molecule for Light-Controlled Activation and Deactivation

“…In recent years, photocleavable protecting groups (PPGs) have become a powerful tool for light-induced release of effector molecules in Chemical Biology. − The list of novel “caged” effector molecules is constantly growing. Besides their biological function, they satisfy a large number of different photophysical requirements including high quantum yield φ, absorption at λ > 350 nm, − high absorption coefficient ε, rapid uncaging, , applicability for two-photon uncaging, , and wavelength-selective photolysis as well as biocompatibility, , and solubility under physiological conditions, cell permeability, − to name a few important design criteria of PPGs.…”

Direct 3-Acylation of Indolizines by Carboxylic Acids for the Practical Synthesis of Red Light-Releasable Caged Carboxylic Acids

“…The development of efficient protection/deprotection sequences for carboxylic acids is important for realizing the on-demand inactivation/activation of their biofunctions for practical use in prodrugs, drug delivery, and molecular biology tools. In particular, photoinduced uncaging systems have been often employed because they can release bioactive carboxylic acids at a desired position and at a specific time point simply upon activation by light irradiation . For this purpose, compounds responsive to long-wavelength light are preferable for biological experiments, mainly due to the high tissue permeability of this type of light .…”