89267-41-4Relevant academic research and scientific papers
Dihydropyridine compound dehydrogenation aromatization method and in use in the drug detection (by machine translation)
-
Paragraph 0101-0107, (2019/01/08)
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)
Photoinduced Aromatization of Dihydropyridines
Lu, Zheng,Yang, Yong-Qing,Li, Hong-Xia
supporting information, p. 4221 - 4227 (2016/11/26)
The combination of tris(bipyridine)ruthenium(II)/visible light/air is found to be effective for the aromatization of many dihydropyridines. A low catalyst loading of just 0.02 mol% is required.
An efficient transition-metal-chloride/sodium-nitrite/TEMPO catalytic system for aerobic oxidative aromatisation of Hantzsch 1,4-dihydropyridines
Lou, Bin-Hui,Chen, Shu-Bin,Wang, Jian,Chen, Ying,Li, Jing-Hua
, p. 409 - 412 (2013/09/12)
A facile and efficient transition-metal-chloride/sodium-nitrite/TEMPO catalytic system for aerobic oxidative aromatisation of Hantzsch 1,4-dihydropyridines in high yields under mild conditions is described.
An efficient, metal-free, room temperature aromatization of Hantzsch-1,4-dihydropyridines with urea-hydrogen peroxide adduct, catalyzed by molecular iodine
Filipan-Litvi?, Mirela,Litvi?, Mladen,Vinkovi?, Vladimir
, p. 5649 - 5656 (2008/09/21)
A mild, highly efficient and metal-free synthetic method for aromatization of 1,4-dihydropyridines employing urea-hydrogen peroxide adduct as oxidant catalyzed by 20 mol % of molecular iodine was developed. The reaction was carried out in ethyl acetate at room temperature and the products were isolated in high to excellent yields. A plausible free-radical mechanism is proposed based on results obtained with derivatives having alkyl and aryl substituents in the 1,4-dihydropyridine ring.
A highly efficient biomimetic aromatization of Hantzsch-1,4-dihydropyridines with t-butylhydroperoxide, catalysed by iron(III) phthalocyanine chloride
Filipan-Litvic, Mirela,Litvic, Mladen,Vinkovic, Vladimir
experimental part, p. 9276 - 9282 (2009/04/05)
Rapid aromatization of Hantzsch-1,4-DHPs with t-butylhydroperoxide catalysed by iron(III) phthalocyanine chloride is described. The reaction proceeds smoothly at room temperature within 1-35 min and the products of high purity were isolated in excellent yields. To explain the reactivity of this catalytical system plausible mechanism have been proposed to involve formation of high-valent oxoferryl species as in cytochrome P450 itself.
Intramolecular electron transfer in the photochemistry of some nitrophenyldihydropyridines
Fasani, Elisa,Fagnoni, Maurizio,Dondi, Daniele,Albini, Angelo
, p. 2037 - 2045 (2007/10/03)
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.
Mild, selective, and high-yield oxidation of hantzsch 1,4-dihydropyridines with lead(IV) acetate
Litvic, Mladen,Cepanec, Ivica,Filipan, Mirela,Kos, Karmen,Bartolincic, Anamarija,Druskovic, Vinka,Tibi, Mohamed Majed,Vinkovic, Vladimir
, p. 23 - 35 (2007/10/03)
Aromatization of 1,4-dihydropyridines with lead(IV) acetate under mild reaction conditions is described. The method is very selective, mild and versatile in the synthesis of different substituted pyridines.
Oxidation of dihydropyridine calcium channel blockers and analogues by human liver cytochrome P-450 IIIA4
Guengerich,Brian,Iwasaki,Sari,Baarnhielm,Berntsson
, p. 1838 - 1844 (2007/10/02)
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.
