- HMPA-catalyzed transfer hydrogenation of 3-carbonyl pyridines and other N-heteroarenes with trichlorosilane
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A method for the HMPA (hexamethylphosphoric triamide)-catalyzed metal-freetransfer hydrogenation of pyridines has been developed. The functional group tolerance of the existing reaction conditions provides easy access to various piperidines with ester or ketone groups at the C-3 site. The suitability of this method for the reduction of other N-heteroarenes has also been demonstrated. Thirty-three examples of different substrates have been reduced to designed products with 45–96% yields.
- Fu, Yun,Sun, Jian
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- A high performance oxidation method for secondary alcohols by inductive activation of TEMPO in combination with pyridine-bromine complexes
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A new TEMPO-mediated catalytic oxidation method in combination with Py·HBr3 (stoichiometric) is developed for oxidation of secondary alcohols to the corresponding ketones. The performance of this oxidizing system is better compared with that of TEMPO method combined with R4NBr3. Poly(4-vinylpyridine)·HBr3 can be used in place of Py·HBr3. The electron-withdrawing substituent at the C-4 position of TEMPO increases the reactivity of TEMPO significantly in the oxidation of electron-deficient alcohols such as polyhaloalkylmethanols. Inductive effect of the substituent of TEMPO is discussed through the characterization of the redox potential of N-O radical by cyclic voltammetry.
- Mei, Zhen-Wu,Omote, Takumi,Mansour, Mounir,Kawafuchi, Hiroyuki,Takaguchi, Yutaka,Jutand, Anny,Tsuboi, Sadao,Inokuchi, Tsutomu
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experimental part
p. 10761 - 10766
(2009/04/11)
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- Quinone derivatives, their production and use.
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Quinone derivatives represented by the general formula (wherein, R1 and R2, which are the same or different, refer to a hydrogen atom, methyl or methoxymethyl group, or R1 and R2 bind together to form-CH=CH-CH=CH-; R3 is a hydrogen atom or methyl group; R? is a nitrogen-containing heterocyclic group which may be substituted; R? is a hydrogen atom, methyl group, hydroxymethyl group which may be substituted, or a carboxyl group which may be (wherein, R' is a hydrogen atom or methyl group); n is an integer from 0 through 12, m is an integer from 0 through 3, and k is an integer from 0 through 7, providing that, when m is 2 or 3, Z and k are able to vary appropri-ately in the repeating unit shown in [ ] ), and the hydro-quinone derivatives thereof, are novel compounds, possess improvement effects of metabolism of poly unsaturated fatty acids, particularly two or more of inhibition of production of fatty acid peroxides, inhibition of production of metabo-lites in 5-lipoxygenase pathway, inhibition of thromboxane A? synthetase, thromboxane A? receptor antagonism and scavenging action of active oxygen species, and of use as drugs, such as antithrombotics, anti-vascular constriction agents, anti-asthma agent, antiallergic agents, therapeutics for psoriasis, agents for improvement in heart, brain and cardiovascular systems, therapeutics for nephritis, active oxygen-eliminating agents, anticancer agents, agents for improvement of control of arachidonate cascade products, etc.
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- Dual Inhibitors of Thromboxane A2 Synthase and 5-Lipoxygenase with Scavenging Activity of Active Oxygen Species. Synthesis of a Novel Series of (3-Pyridylmethyl)benzoquinone Derivatives
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A novel series of (3-pyridylmethyl)benzoquinone derivatives was molecular designed and synthesized for the dual purpose of inhibiting thromboxane A2 and leukotriene biosynthesis enzymes and scavenging active oxygen species (AOS).They were evaluated for inhibition of TXA2 synthase, inhibition of 5-lipoxygenase, and for their scavenging activity of AOS using the thiobarbituric acid method. 2,3,5-Trimethyl-6-(3-pyridylmethyl)-1,4-benzoquinone (24, CV-6504) was the most promising derivative since it showed efficient AOS scavenging activity (inhibition of lipid peroxidation in rat brain homogenates: IC50 = 1.8 10-6 M) as well as potent, specific, and well-balanced inhibitory effects on both enzymes (inhibitory effect on TXA2 synthase in human blood, IC50 = 3.3 10-7 M; inhibitory effect on 5-lipoxygenase in human blood, IC50 = 3.6 10-7 M).In adriamycin-induced proteinuria in a rat model, compound 24 at 10 mg/kg per day (po) suppressed proteinuria by more than 50percent.The proteinuria, however, could not be reduced by single administration of an inhibitor specific for thromboxane A2 synthase or for 5-lipoxygenase .The proteinuria was also not reduced by administration of an AOS scavenger, 2-O-octadecylascorbic acid (4, CV-3611).Triple function compounds such as compound 24 that specifically inhibit both enzymes as well as scavenge AOS possess a variety of pharmacologically beneficial effects.
- Ohkawa, Shigenori,Terao, Shinji,Terashita, Zen-ichi,Shibouta, Yumiko,Nishikawa, Kohei
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p. 267 - 276
(2007/10/02)
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- Certain benzoquinones, naphthoquinones, corresponding hydroquinones which exhibit thromboxane A2 synthetase inhibition or receptor antagonism and the like
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Quinone derivatives represented by the general formula STR1 (wherein, R1 and R2, the same or different, refer to a hydrogen atom, methyl or methoxymethyl group, or R1 and R2 bind together to form --CH=CH--CH=CH--; R3 is a hydrogen atom or methyl group; R4 is a nitrogen-containing heterocyclic group which may be substituted; R5 is a hydrogen atom, methyl group, hydroxymethyl group which may be substituted, or a carboxyl group which may be esterified or amidated; Z is STR2 (wherein, R' is hydrogen atom or methyl group); n is an integer from 0 through 12, m is an integer from 0 through 3, and k is an integer from 0 through 7, providing that, when m is 2 or 3, Z and k are able to vary appropriately in the repeating unit shown in [ ]), and the hydroquinone derivatives thereof, are novel compounds, possess improvement effects of metabolism of polyunsaturated fatty acids, particularly two or more of inhibition of production of fatty acid peroxides, inhibition of production of metabolites in 5-lipoxygenase pathway, inhibition of thromboxane A2 synthetase, thromboxane A2 receptor antagonism and scavenging action of active oxygen species, and of use as drugs, such as antithrombotics, anti-vascular constriction agents, anti-asthma agent, antiallergic agents, therapeutics for psoriasis, agents for improvement in heart, brain and cardiovascular systems, therapeutics for nephritis, active oxygen-eliminating agents, anticancer agents, agents for improvement of control of arachidonate cascade products, etc.
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- Fungicidal Pyridine Derivatives I: α-Trichloromethyl-3-pyridinemethanols
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The title substances, a new type of compounds with fungicidal activity, were synthesized by addition of trichloromethyllithium (and tribromomethyllithium resp.) to various 3-pyridyl ketones at -100 deg C. - Keywords: Fungicides; Pyridinemethanoles; Trichl
- Sauter, Fritz,Stanetty, Peter,Sittenthaler, Wilhelm,Waditschatka, Rudolf
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p. 1427 - 1438
(2007/10/02)
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- Some reactions of 3-cyano(diethylaminocarbonyl, methoxycarbonyl) pyridines with organolithium reagents. Synthesis of stabilized 1,2-, 1,4-, and 1,6-dihydropyridines
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The reaction of 3-cyano 5a, 3-diethylaminocarbonyl 5b, and 3-methoxycarbonylpyridine 5c with alkyllithiums 6 has been investigated as a method of preparing stable dihydropyridines.Reaction of 5a with 6 affords a mixture of 1,2- and 1,6-dihydropyridines 10 and 11, whereas reaction of 5b and 5c with 6 yields a mixture of 1,4- and 1,6-dihydropyridines 11 and 12.The cyano and diethylaminocarbonyl substituents of 5a and 5b are relatively resistant toward attack by the alkyllithium whereas reaction of the methoxycarbonyl substituent of 5c is competitive with addition to the ring.The stabilities of the dihydropyridines prepared are described.
- Din, M. Gamal El,Knaus, Edward E.,Giam, Choo-Seng
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p. 1821 - 1827
(2007/10/02)
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- Ligand interaction of sustituted pyridines with cytochrome P-450.
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A series of pyridyl ketones and alkyl pyridines was evaluated as type II ligands for cytochrome P-450. Activity as type II ligands was evaluated in terms of the lipid solubility and the pKa values of the compounds.
- Born,Early
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p. 850 - 851
(2007/10/02)
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