- SYNTHESIS AND PROPERTIES OF 3,5-DIBROMO-4-OXO-2,2,6,6-TETRAMETHYLPIPERIDINE-1-OXYL RADICAL
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Bromination of 1-hydroxy-4-oxo-2,2,6,6-tetramethylpiperidine gives 3,5-dibromo-1-hydroxy-4-oxo-2,2,6,6-tetramethylpiperidine hydrobromide.Oxidation of the latter generates 3,5-dibromo-4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl radical, which represents a convenient acylating spin trap.
- Zhukova, I. Yu.,Kagan, E. Sh.,Smirnov, V. A.
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Read Online
- New 18F-labeled dienophiles and 18F-labeling method using IeDDA reaction with tetrazines
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The present invention relates to a method of labeling of F-18 radioisotopes using an inverse electron demand Diels-Alder (IeDDA) reaction between a tetrazine compound and a dienophile. A ketone compound according to the present invention easily forms an enamine with a secondary amine in an aqueous solution phase to cause significantly rapid conjugation with a tetrazine compound. Particularly, as the amount of water is increased in the aqueous solution, the reaction proceeds well, so that the compound may be suitable for a bioactive compound, such as a peptide or antibody. Unlike conventional reactions producing different stereoisomers, the reaction produces a small amount of only one type of stereoisomer, besides a main product, and the product can be purified through high performance liquid chromatography, etc. Further, as compared to the conventional ^18F-labeled tetrazine or ^18F-labeled TCO synthesis with a low yield, the ^18F-labeled ketone compound represented by the following chemical formula 1 can be obtained with a high ^18F-labeling yield from a precursor thereof.COPYRIGHT KIPO 2021
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- LIQUID CRYSTAL COMPOSITION CONTAINING NITROGEN-CONTAINING CYCLIC COMPOUND AND LIQUID CRYSTAL DISPLAY DEVICE
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The disclosure shows a liquid crystal composition that contains a compound having an effect of preventing photolysis of the liquid crystal composition and having high solubility in the liquid crystal composition, and that satisfies at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large positive or negative dielectric anisotropy, large specific resistance, high stability to ultraviolet light or heat, and a suitable elastic constant, etc. and so on. The disclosure shows a liquid crystal composition that contains a compound having the following azolidine ring (Q-1) or azepane ring (Q-2), a liquid crystal display device and so on.
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Paragraph 0159; 0162; 0163
(2016/08/17)
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- METAL AMIDES OF CYCLIC AMINES
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Compounds, and oligomers of the compounds, are synthesized with cyclic amine ligands attached to a metal atom. These compounds are useful for the synthesis of materials containing metals. Examples include pure metals, metal alloys, metal oxides, metal nitrides, metal phosphides, metal sulfides, metal selenides, metal tellurides, metal borides, metal carbides, metal silicides and metal germanides. Techniques for materials synthesis include vapor deposition (chemical vapor deposition and atomic layer deposition), liquid solution methods (sol-gel and precipitation) and solid-state pyrolysis. Suitable applications include electrical interconnects in microelectronics and magnetoresistant layers in magnetic information storage devices. The films have very uniform thickness and high step coverage in narrow holes.
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Paragraph 0058; 0064; 0065
(2015/02/19)
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- Synthesis and spectral properties of polymethine-cyanine dye-nitroxide radical hybrid compounds for use as fluorescence probes to monitor reducing species and radicals
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Various hybrid compounds comprised of two types of nitroxide radicals and either a pentamethine (Cy5) or trimethine cyanine (Cy3) were synthesized. The nitroxide radicals were linked either via an ester-bond to one or two N-alkyl carboxyl-terminated groups of Cy5, or via two amido-bonds (aminocarbonyl or carbonylamino group) to the 5-position of the indolenine moieties of Cy5 and Cy3. Changes in fluorescence and ESR intensities of the hybrid compounds were measured before and after addition of Na ascorbate in PBS (pH 7.0) to reduce the radicals. Among the hybrid compounds synthesized, those that linked the nitroxide radicals via an aminocarbonyl residue at the 5-position of the indolenine moieties on Cy5 and Cy3 exhibited a 1.8- and 5.1-fold increase in fluorescence intensity with the reduction of the nitroxide segment by the addition of Na ascorbate, respectively. In contrast, fluorescence intensity was not enhanced in the other hybrid compounds. Thus, the hybrid compounds which exhibited an increase in fluorescent intensity with radical reduction can be used in the quantitative measurement of reducing species such as Fe2+ and ascorbic acid, and hydroxyl radicals. Because these hybrid compounds have the advantage of fluorescing at longer wavelengths-661 (Cy5) or 568 (Cy3) nm, respectively, they can be used to measure radical-reducing species or radicals either in solution or in vivo.
- Sato, Shingo,Tsunoda, Minoru,Suzuki, Minoru,Kutsuna, Masahiro,Takido-uchi, Kiyomi,Shindo, Mitsuru,Mizuguchi, Hitoshi,Obara, Heitaro,Ohya, Hiroaki
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experimental part
p. 2030 - 2039
(2009/03/12)
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- First synthesis of novel spin-labeled derivatives of camptothecin as potential antineoplastic agents
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In an effort to improve the stability of labile lactone ring and water solubility of camptothecin, five novel spin-labeled camptothecin derivatives were synthesized in quantitative yield by a simple modification of the carbodiimide method using the combination of scandium triflate (Sc(OTf)3) and 4-dimethylaminopyridine (DMAP), and the in vitro pharmacokinetic determination of the lactones of representative compound 13a showed that the biological life span of their lactone forms in human and mouse plasma significantly increased when compared with their mother compound camptothecin. Also, the in vitro cytotoxicity of compounds 13a-13e against human bladder cancer T-24 showed either similar or better activity than that of the parent drug, camptothecin, and clinically available drug, irinotecan.
- Liu, Ying-Qian,Tian, Xuan,Yang, Liu,Zhan, Zong-Cheng
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scheme or table
p. 2610 - 2614
(2009/04/11)
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- Synthesis of nitroxide containing polyenes: two chemically modified retinals and their interaction with bacterioopsin
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The synthesis and spectroscopic characterization of two retinal analogues is described, the paramagnetic 3-pyrrolin-1-yloxy analogue 1 and its diamagnetic equivalent, the 3-pyrroline analogue 2.Various aspects of the synthesis of the aminoxy group containing polyenes are discussed.Upon interaction with bacterioopsin, both 1 and 2 are incorporated in the protein and form a system with λmax 459 nm.Neither of the two bacteriorhodopsin analogues is photoactive.ESR spectroscopy data of the system containing 1 show that the ring part of the chromophore in the protein is rigidly fixed in orientation.
- Groesbeek, M.,Lugtenburg, J.
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p. 403 - 409
(2007/10/03)
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- ELECTROCHEMICAL CHLORINATION AND BROMINATION OF DERIVATIVES OF 2,2,6,6-TETRAMETHYLPIPERIDINE
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It was shown that the direction of electrochemical chlorination and bromination in the derivatives of 2,2,6,6-tetramethylpiperidine depends on the acidity of the medium.In an acidic medium 3,5-dibromo-4-oxo-2,2,6,6-tetramethylpiperidine and 3,3,5,6-tetrachloro-4-oxo-2,2,6,6-tetramethylpiperidine respectively are formed from 4-oxo-2,2,6,6-tetramethylpiperidine; derivatives of 2,2,6,6-tetramethylpiperidine not containing a carbonyl group form perbromides during bromination under these conditions.Electrochemical chlorination and bromination in a neutral medium lead to the corresponding N-halogeno derivatives.It was established that 3,3,5,5-tetrachloro-4-oxo-2,2,6,6-tetramethylpiperidine enters into the Favorskii rearrangement with the formation of 3-hydroxy-4-oxo-2,2,5,5-tetramethylpyrrolidine-3-carboxamide.
- Zhukova, I. Yu.,Pozhidaeva, S. A.,Kagan, E. Sh.,Smirnov, V. A.
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p. 626 - 631
(2007/10/02)
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- A Reaction of Nitroxides with Ethyl Mercaptane: A Mild Method for the Conversion of Nitroxides into Their Corresponding Amines
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The mild reduction of the nitroxides 1a-j to the corresponding sterically hindered amines 2a-j by means of ethyl mercaptane is reported.The reaction mixtures of 1a,b,g were analyzed by glc/ms.
- Zakrzewski, Jerzy
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p. 803 - 808
(2007/10/02)
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- INFLUENCE OF CHEMICAL STRUCTURE OF NITROXYL SPIN LABELS ON THEIR REDUCTION BY ASCORBIC ACID
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The influence of structure on the reduction of nitroxyl spin labels by ascorbic acid was examined using both piperidine and pyrrolidine nitroxyls.A five-fold molar excess of ascorbic acid and pH of 7.4 were used.The nitroxyl concentration was measured by electron spin resonance spectrometry.The five-membered (pyrrolidine) nitroxyls were more stable than the six-membered derivatives.Ring substituents also influenced the reaction.The anionic derivatives were more stable than the unionized compounds which, in turn, were more stable than the amines (cations at pH 7.4).
- Couet, W. R.,Brasch, R. C.,Sosnovsky, G.,Lukszo, J.,Prakash, I.,et. al.
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p. 1165 - 1172
(2007/10/02)
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