- 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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- A revised preparation of (4-Acetamido-2,2,6,6-tetramethylpiperidin-1-yl) oxyl and 4-acetamido-2,2,6,6-tetramethyl-1-oxopiperidinium tetrafluoroborate: Reagents for stoichiometric oxidations of alcohols
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Revised preparations of (4-acetamido-2,2,6,6-tetramethylpiperidin-1-yl)oxyl and the corresponding oxoammonium salt, 4-acetamido-2,2,6,6-tetramethyl-1- oxoammonium tetrafluoroborate are presented together with some of the important properties of these two oxidizing reagents. Georg Thieme Verlag Stuttgart New York.
- Tilley, Leon J.,Bobbitt, James M.,Murray, Stephanie A.,Camire, Casey E.,Eddy, Nicholas A.
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p. 326 - 329
(2013/03/14)
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- Reactions of nitroxides. Part X: Antifungal activity of selected sulfur and selenium derivatives of 2,2,6,6-tetramethylpiperidine
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The antifungal activity of nitroxyl radicals - derivatives of 2,2,6,6-tetramethylpiperidine-1-oxyl with reactive substituents 4-isothiocyanato-, 4-isocyano-, and 4-isoselenocyanato- and of N-formyl-, N-thioformyl-, N-selenoformyl-derivatives of 2,2,6,6-tetramethylpiperidine was investigated. Those of the above compounds, which contain a sulfur or selenium atom are the most active against four fungus plant patogens: Botrytis cinerea, Fusarium culmorum, Phytophthora cactorum, Rhizoctonia solani. 4-Isoselenocyanato-2,2,6,6-tetramethylpiperidine-1-oxyl proved to be the most active compound.
- Zakrzewski, Jerzy,Krawczyk, Maria
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scheme or table
p. 514 - 516
(2011/02/28)
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- Synthesis of 2,2,6,6-tetramethylpiperidine derivatives
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Diazotization of 4-amino-2,2,6,6-tetramethylpiperidine in acetic or sulfuric acid affords 2,2,6,6-tetramethyl-1,2,3,6-tetrahydropyridine in high yield. Under the same conditions, the corresponding nitroxyl radical transforms into 4-hydroxy-2,2,6,6-tetrame
- Kashparova,Kagan,Kashparov,Zhukova
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p. 667 - 668
(2007/10/03)
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- Acetylation of sterically hindered diamines
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A process for acetylating diamines having a sterically hindered amino function and a further, sterically unhindered amino function where the acetylation takes place at the sterically unhindered amino function is provided comprises reacting the diamine with ketene. A preferred diamine is 4-amino-2,2,6,6-tetramethylpiperidine (TAD).
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- Non-migrating 1-hydrocarbyloxy hindered amine derivatives as polymer stabilizers
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1-Hydrocarbyloxy substituted hindered amine compounds which also contain a reactive functional group such as hydroxy, amino, oxirane or carboxyl can be chemically attached to selected polymer substrates by condensation reactions to give polymers containing a chemically-bonded, non-migrating stabilizer having excellent stabilization efficacy for protecting said polymer substrate from the adverse effects of actinic light.
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- Synthesis of alpha- and beta-glycosides containing spin labels, as probes for studies of carbohydrate-protein interaction.
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Nitroxide spin-labeled alpha-D-glycopyranosides were synthesized in good yield and in a highly stereoselective manner by reaction of per-O-benzyl-alpha-D-glycopyranosyl bromides with 2,2,6,6-tetramethyl-4-piperidinol under the bromide ion-catalyzed conditions devised by Lemieux et al. After hydrogenolysis, the deblocked intermediates were oxidized to give the desired, spin-labeled alpha-D-glycopyranosides. Nitroxide spin-labeled beta-D-glycopyranosides, as well as a beta-maltoside, were synthesized by standard methods. The synthesis is also described of 2-amino-2-deoxy-D-glucose and -D-galactose derivatives having a spin label at C-2, and of the spin-labeled compound 1-[4-(beta-D-galactopyranosyloxy)phenyl]-3-(2,2,6,6-tetramethylpiperidin-1-oxyl -4-yl)-2-thiourea.
- Plessas,Goldstein
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p. 211 - 220
(2007/10/02)
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