Pyridazino-1,3a,6a-Triazapentalenes as Versatile Fluorescent Probes: Impact of Their Post-Functionalization and Application for Cellular Imaging

Abstract

Pyridazino-1,3a,6a-triazapentalenes (PyTAP) are compact fused 6/5/5 tricyclic scaffolds which exhibit promising fluorescent properties. Chemically stable, they can be post-functionalized using standard Pd-catalyzed cross-coupling chemistry. Several original PyTAP bearing additional unsaturated substituents in positions 2 and 8 were synthetized and their spectroscopic properties analyzed. They have been successfully tested as fluorescent probes for cellular imaging.

Design, Synthesis, Computational Studies, and Anti-Proliferative Evaluation of Novel Ethacrynic Acid Derivatives Containing Nitrogen Heterocycle, Urea, and Thiourea Moieties as Anticancer Agents

“…Subsequently, we have prepared two novel EA derivatives modified onto the carboxylic acid part with PyTAP fluorescent molecules [20] (Scheme 3). The preparation of the pyridazino-1,3a,6a-triazapentalene (PyTAP) pharmacophores 19 and 20 was achieved according to procedures from the literature [21]. Compound 22 was prepared using a Sonogashira-type coupling reaction between compound 19 and EA derivative 21 bearing an alkyne group.…”

“…The synthesis of the key intermediate compounds 13(a-c), 14b, 15b, 19, 20, and 21 were prepared according to references [19,21,[30][31][32].…”

Synthesis, Photophysical Properties, and Aromaticity of Pyrazine-Fused Tetrazapentalenes

“…For instance, the 1,3a,6a-triazapentalene (TAP) is a zwitterionic aromatic heterocycle with three consecutive nitrogen atoms of which two are at the bicyclic ring junction. The intramolecular charge transfer that can occur in this family of compounds has been particularly studied to produce compact organic fluorophores, either as simple bicyclic systems − or as larger molecules when the azapentalene bicyclic system is fused to various heterocyclic scaffolds (Scheme a). − They possess an amphiphilic character particularly interesting for biological imaging applications. − With an additional nitrogen atom, zwitterionic tetraazapentalene analogue (TeAP) remains more confidential and were developed for energetic applications. − Among them, z-TACOT and derivatives exhibit a unique pattern with four consecutive nitrogen atoms arranged in a Z shape, which was even recently flanked with various energy-rich fragments such as benzofuroxan or 1,2,3,4-tetrazine 1,3-dioxane. − …”

A Novel and Reactive Fluorescent “Turn‐on” Probe Based on Benzimidazole Derivative for Selective CN−Detection

“…The fluorescent chemical sensors exhibit many satisfactory characteristics such as high sensitivity and selectivity, visual detection and optical imaging [53–68] . However, some sensors still suffer from complex preparation processes, high costs, demanding detection conditions or low sensitivity [69–75] . Therefore, it is very necessary for the development of simple, novel, and high efficient sensors for rapidly CN − detection.…”