A Two‐Photon Ratiometric Sensing Platform Based on Solid‐State Luminescent Benzocoumarin: Application to Prolonged Bioimaging of Hydrogen Peroxide

Abstract

Fluorescent probes provide essential tools for studying biological systems. For the prolonged imaging of cellular analytes, the fast clearance of small‐molecular probes and products is a matter of concern in the quantitative analysis. Activatable probes that produce insoluble products inside cells can be used for prolonged imaging, but those with ratiometric imaging capability are rare. We disclose a novel sensing platform that is capable of prolonged imaging, in addition to ratiometric signaling for reliable quantitative analysis. Specifically, 3‐(pyridin‐4‐yl)‐8‐(pyrrolidin‐1‐yl)‐2H‐benzo[g]chromen‐2‐one and its pyridinium salt as a product/probe couple constitute the ratiometric sensing platform. As the former dye produces highly emissive insoluble nanoaggregates inside cells, a fluorescent probe in the latter form enables prolonged imaging of the target analyte in cells as well as in tissue by two‐photon microscopy.

Expedient synthesis of 1,2,4-triazinyl substituted benzo[c]coumarins via double oxidation strategy

“…Azaheterocyclic coumarin derivatives provide one of most important photophysical-active compounds [1][2][3]. Due to good photophysical properties, such as high quantum yields and long-wavelength absorption/emission, various push-pull coumarins, containing azaheterocyclic fragment, have been studied as sensors [3][4][5] and fluorescent probes [6][7][8], components of organic light-emitting diodes (OLED) [9,10] and solar cells [11,12]. For example, coumarin-based terpyridine-zinc complex (Figure 1) demonstrated sensing ability for pyrophosphate (PPi) in aqueous media and was successfully applied to fluorescence imaging for PPi in Hi-5 cells and Caenorhabditis elegans [13].…”

Heptafluorobutyric Acid Catalyzed Cross-Dehydrogenative Coupling of 7-Aminocoumarins with 1,2,4-Triazines: A Straightforward Pathway to 3-Triazinyl-7-aminocoumarins

“…14 Moreover, 3-[6-(methylsulfanyl)pyridin-2-yl]-7-(piperazin-1-yl)coumarin has been used for the treatment of spinal muscular atrophy. 15 Most synthetic approaches to 3-azinyl-7-aminocoumarins exploit either annulation of the pyrone ring through interaction of the corresponding coumarin precursors with pyridylacetic acid (Scheme 1, a) 9,10,12,[16][17][18][19][20] or construction of azine core to 3-acetyl-7-aminocoumarin derivatives (Scheme 1, b). 14,21,22 In addition, only a few studies have described the synthesis of 3-azinylcoumarins through the transition-metal-catalyzed C-X/C-Y cross-coupling reactions (Scheme 1, c).…”