- Synthesis and fluorescence properties of six fluorescein-nitroxide radical hybrid-compounds
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Six fluorescein-nitroxide radical hybrid-compounds (2ab, 3ab, 4, and 5) were synthesized by the condensation of 5- or 6-carboxy-fluorescein and 4-amino-TEMPO (2ab), 5- or 6-aminofluorescein and 4-carboxy-TEMPO (3ab), and fluorescein and 4-carboxy-TEMPO (4), or by reaction of the 3-hydroxyl group of fluorescein with DPROXYL-3-ylmethyl methanesulfonate (5). Fluorescence intensities (around 520 nm) after reduction of the radical increased to 1.43-, 1.38-, and 1.61-folds for 2a, 2b and 3b respectively; 3a alone exhibited a decrease in intensity on reduction. Since 4 was readily solvolyzed in PBS or even methanol to afford fluorescein and 4-carboxy-TEMPO, its fluorescence change could not be measured. Hybrid compound 5 containing an ether-linkage between the fluorescein phenol and 3-hydroxymethyl-DPROXYL hydroxyl centers, was stable and on reduction, showed a maximum increase (3.21-fold) in relative fluorescence intensity in PBS (pH 5.0), despite its remarkably low absolute fluorescence intensity.
- Sato, Shingo,Endo, Susumu,Kurokawa, Yusuke,Yamaguchi, Masaki,Nagai, Akio,Ito, Tomohiro,Ogata, Tateaki
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supporting information
p. 66 - 71
(2016/07/06)
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- Fluorescent human EP3 receptor antagonists
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Exchange of the lipophilc part of ortho-substituted cinnamic acid lead structures with different small molecule fluorophoric moieties via a dimethylene spacer resulted in hEP3R ligands with affinities in the nanomolar concentration range. Synthesized compounds emit fluorescence in the blue, green, and red range of light and have been tested concerning their potential as a pharmacological tool. hEP3Rs were visualized by confocal laser scanning microscopy on HT-29 cells, on murine kidney tissues, and on human brain tissues and functionally were characterized as antagonists on human platelets. Inhibition of PGE2 and collagen-induced platelet aggregation was measured after preincubation with novel hEP3R ligands. The pyryllium-labeled ligand 8 has been shown as one of the most promising structures, displaying a useful fluorescence and highly affine hEP3R antagonists.
- Tomasch, Miriam,Schwed, J. Stephan,Kuczka, Karina,Meyer Dos Santos, Sascha,Harder, Sebastian,Nuesing, Rolf M.,Paulke, Alexander,Stark, Holger
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supporting information
p. 774 - 779
(2012/11/13)
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- PROCESS FOR THE PREPARATION OF 5-/6-NITROFLUORESCEIN
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A process for the preparation of a mixture of 3',6'-dihydroxy-6-nitrospiro[2-benzofuran-3,9'-xanthene]-1-one and 3',6'-dihydroxy-5-nitrospiro[2-benzofuran-3,9'- xanthene]-1-one comprising the steps of:- (a) reacting 4-nitrophthalic acid or 4-nitrophthalic anhydride with benzene-1,3- diol in methanesulphonic acid; (b) quenching the reaction in step (a) with a solvent to precipitate product; (c) isolating the precipitate; (d) heating the precipitate in water in order to hydrolyse any methansulphonic acid ester present.
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Page/Page column 9-10
(2010/09/03)
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- Solvent-free synthesis of sulfonephthaleins, sulfonefluoresceins and fluoresceins under microwave irradiation
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An efficient solvent-free synthesis of sulfonephthaleins, sulfonefluoresceins and fluoresceins under microwave irradiation is reported.
- Cihelnik, Simon,Stibor, Ivan,Lhotak, Pavel
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p. 1779 - 1789
(2007/10/03)
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