- Dihydropyridine compound dehydrogenation aromatization method and in use in the drug detection (by machine translation)
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Relates to dihydropyridine compound dehydrogenation aromatization method and in use in the drug detection, compounds such as nifedipine, amlodipine, Cini horizontal, Lacidipine, felodipine, NIKA of amlodipine, nitrendipine, nimodipine and BANI to equal, the method in acidic aqueous solution in the presence of a nickel-containing catalyst in the oxidation reaction of the then purified to realize. The method can be used for preparing this kind of drug detection and quality monitoring of the impurity reference substance, also can be used for quality detection process is used in the instrument of the instrument such as the dissolution of the design reference, drug synthesis process and the design of the manufacturing process of the preparation of the reference, in order to avoid impurities introduced by the process channels, in addition can also be dihydropyridine compound of related synthetic process route provides design provides a reference. The reaction can be in the acidic aqueous solution, to a suitable oxidant (such as air) as the oxidizing agent, in the presence of nickel, at normal temperature to carry out dehydrogenation aromatization reaction, mild reaction conditions, the target compound of high conversion rate, the operation is simple, by-product little small pollution to the environment, is a completely environment-friendly preparation process. (by machine translation)
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Paragraph 0083-0089
(2019/01/08)
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- For 1, 4 - dihydro pyridine compound to prepare the corresponding pyridine compound (by machine translation)
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The invention discloses a method for the 1, 4 - dihydro pyridine compound to prepare the corresponding pyridine compound. The method of the invention is: will be 1, 4 - dihydro pyridine compound, eosin Y of the four n-butyl ammonium salt, potassium carbonate is added to the organic solvent with the water in the mixed solvent of stirring and mixing, inject the air in visible light irradiation under the conditions of reaction, to be after the reaction, by adding ethyl acetate, respectively water, saturated ammonium chloride washing, removal of inorganic alkali and adjust the system to subacid, in the organic phase by adding a small amount of activated carbon to remove the pigment, then dried with anhydrous sodium sulfate, turns on lathe does, recrystallize and obtain the corresponding pyridine compound. The method of the invention compared with the prior art has to oxygen in air as the oxidizing agent, is cheap and easy to get; to sunlight as the energy source, so that the industrial production more favorable; catalytic amount of the use of non-metal catalyst, reduces the cost of synthesizing, avoiding the noble metal in the accumulation of drug in the synthesis. (by machine translation)
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Paragraph 0022-0024
(2017/08/19)
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- Metal-free-mediated oxidation aromatization of 1,4-dihydropyridines to pyridines using visible light and air
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A metal-free and environmentally friendly aerobic aromatization photosensitized by organic dye eosin Y bis(tetrabutyl ammonium salt) (TBA-eosinY) has been developed. With the aid of K2CO3, the aerobic catalytic system converts 1,4-dihydropyridines to their corresponding pyridine derivatives efficiently under visible light irradiation (λ=450 nm) at room temperature.
- Wei, Xiaojing,Wang, Lin,Jia, Wenliang,Du, Shaofu,Wu, Lizhu,Liu, Qiang
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p. 1245 - 1250
(2015/02/05)
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- Study on the oxidation of C4-phenolic-1,4-dihydropyridines and its reactivity towards superoxide radical anion in dimethylsulfoxide
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Electrochemical characterization on glassy carbon electrode (GCE) and reactivity with superoxide radical anion in aprotic medium of three new synthesized C4-phenolic-1, 4-dihydropyridines is reported. Voltammetry, coulometry, controlled-potential electrolysis (CPE), UV-vis spectroscopy, 1H NMR techniques were employed for the characterization of title compounds. The oxidation mechanism involves initially an oxidation process on the phenol moiety with the formation of the corresponding quinone followed by a second one affecting the dihydropyridine ring to give the pyridine derivative. Both processes appeared irreversible in character. Cyclic voltammetry was used to generate O2- by reduction on GCE of molecular oxygen in DMSO. The reactivity of DHPs towards O2- was directly measured by the anodic current decay of the radical in the presence of increasing concentration of tested 1,4-dihydropyridines and compared with the reaction of the reference antioxidant, Trolox. The linear correlations obtained between the anodic current of O2- and compound concentrations in the range between 0.01 mM and 1.00 mM allowed the determination of both the DHP antioxidant index (AI) and the concentrations needed to consume 50% of O2-. Synthesized C4-phenolic 1,4-dihydropyridines exhibited significant scavenging capacity towards superoxide radical anion higher than Trolox and tested commercial 1,4-dihydropyridines.
- Salazar, Ricardo,Navarrete-Encina,Squella,Barrientos,Pardo-Jiménez,Nú?ez-Vergara, Luis J.
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experimental part
p. 841 - 852
(2011/03/22)
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- Reactivity of C4-indolyl substituted 1,4-dihydropyridines toward superoxide anion (O2O) in dimethylsulfoxide
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Reactivity of two new C4-indolyl substituted 1,4-dihydropyridines (1,4-DHPs) toward superoxide anion (O2-) in dimethylsulfoxide (DMSO) is reported. Reactivity was followed by electrochemical and spectroscopic techniques. Gas chromatography-mass spectrometry (GC-MS) was used to identify the final products of the reaction. C4 indolyl-substituted-1,4-DHPs reacted toward O2O at significant rates, according to the calculated kinetic rate constants. Results are compared with 4-phenyl-DHP and the commercial 1,4-DHPs, nimodipine, nisoldipine, and amlodipine. Indolyl-substituted 1,4-DHPs were more reactive than the commercial derivatives. The direct participation of proton of the 1-position of the secondary amine in the quenching of O 2 was demonstrated.
- Salazar, Ricardo,Navarrete-Encina,Squella,Camargo,Nunez-Vergara, Luis J.
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scheme or table
p. 569 - 577
(2010/07/02)
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- Intramolecular electron transfer in the photochemistry of some nitrophenyldihydropyridines
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4-Phenyl-1,4-dihydropyridine-3,5-dicarboxylates contain two π chromophores separated by an sp3 carbon. The lowest singlet is localized on the dihydropyridine moiety (1PyH2-Ph) and emits a blue fluorescence (with close to unitary efficiency in glass at 77 K). In 3-nitrophenyl derivatives (PyH2-PhNO2, some of which are photolabile drugs) the fluorescence is completely quenched. Reasonably, this is due to intramolecular electron transfer between the close-lying donor and acceptor moieties to give the charge-separated species (PyH2 .+-PhNO2.-). In EPA glass at 77 K, back-electron transfer gives the dihydropyridine-localized triplet ( 3PyH2-PhNO2), which emits a yellow phosphorescence. In solution, deprotonation from the radical cation on the dihydropyridine moiety initiates rearomatization, finally giving Py-PhNO 2 with low quantum yield (5 × 10-4 to 5 × 10-3, increasing up to 0.013 by irradiation at 254 nm, where direct excitation of the nitrophenyl chromophore contributes). In the presence of triethylamine, the reaction changes to neat reduction of the nitro group. When a tethered alkylamino group is present, oxidative degradation of that moiety occurs, again via an electron-transfer intramolecular process. This has been found with the drug nicardipine, where photodegration is more efficient (Φ 0.02 to 0.1). Donor-acceptor dyads of this type, easily available through the Hantzsch synthesis, may be useful for building new photoinduced electron-transfer systems.
- Fasani, Elisa,Fagnoni, Maurizio,Dondi, Daniele,Albini, Angelo
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p. 2037 - 2045
(2007/10/03)
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- Reactivity of 1,4-dihydropyridines toward alkyl, alkylperoxyl radicals, and ABTS radical cation
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A series of C4-substituted 1,4-dihydropyridines (DHP) with either secondary or tertiary nitrogen in the dihydropyridine ring were synthesized. All of these compounds together with some commercial DHP derivatives were tested for potential scavenger effects toward alkyl, alkylperoxyl radicals, and ABTS radical cation in aqueous media at pH 7.4. Kinetic rate constants were assessed either by UV/vis spectroscopy or GC/MS techniques. Tested compounds reacted faster toward alkylperoxyl radicals and ABTS radical cation than alkyl ones. N-Ethyl-substituted DHPs showed the lowest reactivity. Kinetic results were compared with either trolox or nisoldipine. Using deuterium kinetic isotope effect studies, we have proved that the hydrogen of the 1-position of the DHP ring is involved in the proposed mechanism. This fact is mostly noticeable in the case of alkyl radicals. In all cases, the respective pyridine derivative was detected as the main product of the reaction.
- Lopez-Alarcon,Navarrete,Camargo,Squella,Nunez-Vergara
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p. 208 - 215
(2007/10/03)
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- Pyridyl compounds and pharmaceutical compositions containing them
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The present invention is concerned with new pyridine double esters of formula (I), their acids, and pharmaceutically acceptable salts. These compounds can be obtained by oxydation of the corresponding 1,4-dihydropyridines, and they are useful as cardioprotective agents in pharmaceutical compositions.
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- Oxidation of dihydropyridine calcium channel blockers and analogues by human liver cytochrome P-450 IIIA4
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A series of 21 different 4-substituted 2,6-dimethyl-3-(alkoxycarbonyl)-1,4-dihydropyridines was considered with regard to oxidation to pyridine derivatives by human liver microsomal cytochrome P-450 (P-450). Antibodies raised against P-450 IIIA4 inhibited the microsomal oxidation of nifedipine and felodipine to the same extent, as did cimetidine and the mechanism-based inactivator gestodene. Gestodene was ~ 103 times more effective an inhibitor than cimetidine, on a molar basis. When rates of oxidation of the 1,4-dihydropyridines were compared to each other in different human liver microsomal preparations, all were highly correlated with each other with the exceptions of a derivative devoid of a substituent at the 4-position and an N1-CH3 derivative. A P-450 IIIA4 cDNA clone was expressed in yeast and the partially purified protein was used in reconstituted systems containing NADPH-cytochrome P-450 reductase and cytochrome b5. This system catalyzed the oxidation of all of the 1,4-dihydropyridines except the two for which poor correlation was seen in the liver microsomes. Principal component analysis supported the view that most of these reactions were catalyzed by the same enzyme in the yeast P-450 IIIA4 preparation and in the different human liver microsomal preparations, or by a closely related enzyme showing nearly identical properties of catalytic specificity and regulation. The results indicate that the enzyme P-450 IIIA4 is probably the major human catalyst involved in the formal dehydrogenation of most but not all 1,4-dihydropyridine drugs.
- Guengerich,Brian,Iwasaki,Sari,Baarnhielm,Berntsson
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p. 1838 - 1844
(2007/10/02)
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- Ischaemia or hypoxia controlling compositions containing pyridinecarboxylic acid esters
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Pyridinecarboxylic acid esters of the formula STR1 in which R is an optionally substituted aryl or heterocyclic radical, R1 and R2 are hydrogen, alkyl, aryl, aralkyl, acyloxyalkyl or hydroxyalkyl, or R1 with X forms a carb
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- Medicaments having antihypoxic and ischaemia-protective activity
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A method of controlling damage to the central nervous system of a patient which comprises administering to such patient a central nervous system-controlling effective amount of a pyridine derivative of the formula STR1 in which R is an optionally substitu
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- Nimodipine: Synthesis and metabolic pathway
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Key step of the synthesis of the calcium antagonistic cerebral vasodilator (±) isopropyl-2-methoxyethyl 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylate (Bay e 9736, nimodipine) is the cyclising Michael addition. A pharmacokinetic study with 14C-nimodipine in the rat revealed as major metabolites the dihydropyridines as well as the pyridines. A potential metabolic pathway is discussed involving ether cleavage and oxidation to the pyridine form as primary biotransformation steps. Reference metabolites were synthesized using 1,4-dihydropyridines with appropriate functionalities as precursors.
- Meyer,Wehinger,Bossert,Scherling
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p. 106 - 112
(2007/10/02)
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