Studies on Novel Syntheses of Fluorecent Tripodal Hexadentate Iigands and Than Application to fluorescent Probes for Microscopic Observation of Cells

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In this project, we investigated syntheses of novel fluorescent bidentate and hexadentate ligands and their application to the fluorescent probes for microscopic observation of cells. The following points became dear.1.Anew fluorescent bidentate ligand (a), 3-hydroxy-4(1H)-pyridinone directly attached to quinoxaline, was synthesized. 2.Anew fluorescent bidentate ligand (b), 6-(2',3'-dihydroxybenzyl)amino-2,3-dimorpholino quinoxaline, was synthesized. 3.A chiral quinoxaline (c) bearing the L-praline residue at C-6 position was synthesized. 4.A fluorescent imidazopyrazine (d) bearing diaryl substituents at C-6 and C-8 positions was synthesized 5.Unfortunately, the desired fluorescent tripodal hexadentate ligands could not be obtained owing to the insolubility of synthetic intermediates. 6.The bidentate ligand (a) formed 3:1 complexes with Fe(III), Al(III), Ga(III), and Cr(III). The fluorescence was efficiently quenched by the metal complex formation via the Perrin model of static quenchi … More ng, the quenching efficiency being in order of Fe(III)>>Al(III)>Ga(M)>Cr(III). The fluorescence was recoverd by removal of Fe(III) with N-benzoyl desfenioxamine B. 7.In case of bidentate ligand (b), a unique absorption band due to the intramolecular charge transfer from the catechol moiety to electro-defident quinoxaline was observed under basic conditions. 8.The derivatization of mcemic naproxen, ibuprofen, and 2 phenylpropionic acid with chiral quinoxaline (c) afforded the diastereomers, which were dearly separated within 16 min on reversed phase HPLC with a detection limit of 5 pmol/10 μL injection volume at S/N=5. 9.Imidazopyrazine (d) showed enough sensitivity to superoxide in comparison with luminol and appears to be capable of superoxide detection. Further, imidazopytazine (d) exhibited the pH dependent bimodal chemiluminescence. These properties of imidazopyrazine(d) allows us to apply it for simultaneous detection of the two concurrent events, superoxide evaluation and pH titration, in biological systems. Less