- Preparation method of pyridine derivative (by machine translation)
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To the method, piperidine-4-one hydrochloride is used as a raw material, and a series of pyridine derivatives are obtained through halogenation reaction and elimination reaction. The reaction is eliminated by reacting piperidine-4-one hydrochloride with a specific amount of the 3,5 - halogenating agent in a halogenation 3, 3, 5 - reaction with a halogen-3, 3, 5, 5 - based reaction, followed by reaction with a pyridine derivative of a hydroxyl group, an amino group 4 - or a dimethylamino group, respectively, by eliminating the reaction with a different kind of basic agent. The method is simple and convenient to operate, mild in condition, short in technological process, low in waste water yield, environment-friendly, low in cost and beneficial to green industrial production of the pyridine derivative. (by machine translation)
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Paragraph 0099-0102
(2019/12/02)
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- Synthesis of N-Heterocycles-Fused Azasilines by Palladium-Catalyzed Si-Si Bond Activation
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Azasilines fused nitrogen heterocycles are prepared in excellent yields (from 74 to 98 % according to the structures) for the first time in one operation with high regio- and stereoselectivities. The key step consists of an intramolecular palladium-cataly
- No?l-Duchesneau, Ludovik,Maddaluno, Jacques,Durandetti, Muriel
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p. 4154 - 4160
(2019/05/21)
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- Synthesis of pyrrolo[1,2-a]naphthyridines by Lewis acid mediated cycloisomerization
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Pyrrolo[1,2-a]naphthyridines were synthesized from 3-alkynyl-2-([1H]-pyrrol-1-yl)pyridines and 3-alkynyl-4-([1H]-pyrrol-1-yl)pyridines by cycloisomerization. The reactions are performed by application of the Lewis acids PtCl2 or Bi(OTf)3 without the need of further additives. With the described methods a number of derivatives containing a variety of functional groups have been synthesized in up to 78% yield.
- Flader, Anika,Parpart, Silvio,Ehlers, Peter,Langer, Peter
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supporting information
p. 3216 - 3231
(2017/04/21)
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- Synthesis and biological evaluation of 4-(2-fluorophenoxy)-3,3′-bipyridine derivatives as potential c-met inhibitors
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Six series of novel 4-(2-fluorophenoxy)-3,3′-bipyridine derivatives conjugated with aza-aryl formamide/amine scaffords were designed and synthesized through a structure-based molecular hybridization approach. The target compounds were evaluated for c-Met kinase inhibitory activities and cytotoxicity against four cancer cell lines (HT-29, A549, MKN-45 and MDA-MB-231) in vitro. Most compounds exhibited moderate to excellent potency, and the most promising candidate 26c (c-Met kinase IC50 = 8.2 nM) showed a 4.7-fold increase in cytotoxicity against c-Met-addicted MKN-45 cell line in vitro (IC50 = 3 nM), superior to that of Foretinib (IC50 = 23 nM). The preliminary structure-activity relationship indicated that a 1H-benzo [e] [1,3,4]thiadiazine-3-carboxamide-4,4-dioxide moiety as linker contributed to the antitumor potency.
- Zhao, Sijia,Zhang, Yu,Zhou, Hongyang,Xi, Shuancheng,Zou, Bin,Bao, Guanglong,Wang, Limei,Wang, Jiao,Zeng, Tianfang,Gong, Ping,Zhai, Xin
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- Enantioselective halocyclization using reagents tailored for chiral anion phase-transfer catalysis
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A chiral anion phase-transfer system for enantioselective halogenation is described. Highly insoluble, ionic reagents were developed as electrophilic bromine and iodine sources, and application of this system to o-anilidostyrenes afforded halogenated 4H-3,1-benzoxazines with excellent yield and enantioselectivity.
- Wang, Yi-Ming,Wu, Jeffrey,Hoong, Christina,Rauniyar, Vivek,Toste, F. Dean
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supporting information; experimental part
p. 12928 - 12931
(2012/10/08)
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- Compounds and their use
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This invention relates to compounds, pharmaceutical compositions, and methods of using the disclosed compounds for inhibiting PARP.
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- Mild regioselective halogenation of activated pyridines with N-bromosuccinimide
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Regioselective mono and dihalogenations of amino, hydroxy and methoxy pyridines (2-, 3-, and 4-substituted) as well as 2,6-dimethoxy pyridine with N-bromosuccinimide in different solvents have been studied. Reactivity of the substrates decreases in the order amino>hydroxy>methoxy and regioselectivity depends on the position of the substituent (2-substituted > 3-substituted). In most of the cases we obtained monobrominated derivatives regioselectively and in high yields. Hydroxy and amino pyridines can also be dibrominated in almost quantitative yield with 2 equivalents of NBS.
- Canibano,Rodriguez,Santos,Sanz-Tejedor,Carreno,Gonzalez,Garcia-Ruano
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p. 2175 - 2179
(2007/10/03)
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- Novel synthetic strategy of carbolines via palladium-catalyzed amination and arylation reaction
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Four parent carbolines and the corresponding 5- or 9-methylsulfonyl derivatives were synthesized by the palladium-catalyzed intramolecular arylation reaction of ortho-bromo-substituted anilinopyridines which were prepared by the palladium-catalyzed amination reaction of iodobenzenes with aminopyridines. Carbazole and its 9-methylsulfonyl derivative were also synthesized by the same method.
- Iwaki, Takehiko,Yasuhara, Akito,Sakamoto, Takao
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p. 1505 - 1510
(2007/10/03)
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- Rate-Determining Steps in Michael-Type Additions and E1cb Reactions in Aqueous Solution
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Rates of equilibration of a series of 10 substituted pyridines and five Michael acceptors (CH2=CHZ, Z = CHO, COCH3, SO2CH3, CN and CONH2) with the corresponding N(ZCH2CH2) pyridinium cations have been measured in aqueous solution at ionic strength 0.1 and 25 deg C.Analysis of the dependence of the pseudo-first-order rate constants for equilibration as a function of acceptor concentration and of pH allows the evaluation of the second-order rate constants (kNu) for the nucleophilic attack of each of these pyridines upon each of these acceptors and also the second-order rate constants (kOH) for the hydroxide ion catalyzed E1cb elimination reaction which is the microscopic reverse of each of these Michael-type addition reactions.Broensted-type plots for each of these processes as a function of the basicity of the substituted pyridine are concave down for each of Z = CHO, COCH3, and CN and are consistent with a change from rate-determining nucleophilic attack for the more basic pyridines to rate-determining protonation of the carbanionic intermediate by a water molecule for less basic pyridines and the corresponding microscopic reverse processes in the elimination reactions.The "break" in these Broensted-type plots is shown to occur at a pyridine basicity that is a function of the Z-activating substituent.Broensted β1g and βnuc are evaluated for each rate-determining step (wherever accessible); these two parameters are shown to pass through minima as a function of reactivity. βeq is shown to be a simple linear function of reactivity (as log kNu) for nucleophilic addition to the acceptor species, although Keq is relatively insensitive to the nature of the Z-activating substituent.
- Heo, Christina K. M.,Bunting, John W.
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p. 3570 - 3578
(2007/10/02)
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- CONDENSED HETEROAROMATIC RING SYSTEMS. XXII. SIMPLE AND GENERAL SYNTHESIS OF 1H-PYRROLOPYRIDINES
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Four kinds of 1H-pyrrolopyridines having no substituent were simply and easily synthesized by the palladium-catalyzed reaction of easily available nitropyridine derivatives with (Z)-1-ethoxy-2-tributylstannylethene as a key reaction.
- Sakamoto, Takao,Satoh, Chisato,Kondo, Yoshinori,Yamanaka, Hiroshi
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p. 2379 - 2384
(2007/10/02)
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- A Change in the Rate-Determining Step in the E1cB Reactions of N-(2-(4-Nitrophenyl)ethyl)pyridinium Cations
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Second-order rate constants have been measured (aqueous solution, I = 1.0, 25 deg C) for the hydroxide ion catalyzed elimination reactions of 12 N-(2-(4-nitrophenyl)ethyl)pyridinium cations (3) bearing a variety of substituents in the pyridine ring.Broensted plots as a function of the basicity of the pyridine leaving group are concave-down, which is consistent with a change in rate-determining step within an E1cB mechanism.These plots are characterized by βlg = -0.17 for the rate-determining deprotonation for pKBH lg = -0.39 for the rate-determining expulsion of the pyridine nucleofuge from the carbanionic intermediate for pKBH > 6.5.Elimination reactions in basic D2O occur without any significant incorporation of deuterium into the 4-nitrostyrene product, and require the presence of a hydrogen-bonded carbanionic intermediate in which nucleofuge expulsion occurs faster than exchange of hydrogen-bonding water molecules.Rate-determining deprotonation in these elimination reactions occurs 50-fold more slowly than for the corresponding reactions of the N-quinuclidinium cations that have also been reported to have βlg = -0.17, but which do not show an analogous change in the rate-determining step upon variation of the nucleofuge basicity.The analogous elimination of the 1-methyl-3-imidazolium cation occurs a further 30-fold more slowly than that predicted for 3 having a pyridine leaving group of the same basicity as 1-methylimidazole.The E1cB reactions of 3 are similar to the analogous reactions of N-(2-cyanoethyl)pyridinium cations (1) in displaying a change in the rate-determining step with nucleofuge basicity; however, theβlg values for 1 and 3 are quite different for both k1 and k2/k-1.
- Bunting, John W.,Kanter, James P.
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p. 6950 - 6954
(2007/10/02)
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- Equilibration of N-(2-cyanoethyl)pyridinium cations with substituted pyridines and acrylonitrile. A change in rate-determining step in an E1cb reaction
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The rates of equilibration of N-(2-cyanoethyl)pyridinium cations (1) with the corresponding pyridines and acrylonitrile have been measured in aqueous solutions of ionic strength 0.1 at 25 °C. Second-order rate constants (kOH) have been obtained for the hydroxide ion catalyzed elimination reactions of 16 ring-substituted 1 having pyridine leaving groups of pKBH in the range 1.5-9.7. Bronsted plots of log kOH vs pKBH are "concave down" with two distinct linear regions having β1g = -0.30 (for pKBH 1g = -0.93 (for pKBH > 5.8). This observation is consistent with a change in rate-determining step within an E1cb reaction mechanism from rate-determining deprotonation of 1 (i.e., (E1cb)irrev) for pKBH rev) for pKBH > 5.8. This interpretation is supported by 1H NMR spectral observations in basic D2O, which show no incorporation of deuterium into the acrylonitrile product for pKBH BH > 5.8. Rates of nucleophilic attack of pyridines and pyridinone anions (pKBH > 6) upon acrylonitrile have also been measured. These display a linear Br?nsted plot of βnuc = 0.20. Combination of β1g and βnuc gives βeq = 0.13 for the Michael-type addition of pyridinium cations to acrylonitrile to produce 1. Although the rates of the addition of pyridines of pKBH nuc = 0.20 for pyridines of pKBH > 5.8 to rate-determining protonation of the carbanionic intermediate with βnuc = 0.83 for pyridine nucleophiles of pKBH irrev region but is extremely weak under the current experimental conditions.
- Bunting, John W.,Toth, Andrea,Heo, Christina K. M.,Moors, Rodney G.
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p. 8878 - 8885
(2007/10/02)
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- Directed Lithiation of 4-Halopyridines: Chemoselectivity, Regioselectivity and Application to Synthesis
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4-Chloro and 4-fluoropyridines were ortho-lithiated by n-butyllithium-TMEDA chelate or lithium diisopropylamide at low temperature.The resulting 3-lithio 4-halopyridines were reacted with electrophiles which led to various 3,4-disubstituted pyridines.The versatility of this functionalization is enhanced by the 4-halogen reactivity towards nucleophiles such as water, methylate and amines.Some of the 3,4-disubstituted synthons were annelated to naphthyridine, xanthone and coumarin or condensed to Hantzsch-ester or to "chlotrimazol" analogues.Lithiation of 4-fluoropyridine led in one step to 3,4-pyridyne, which was trapped by cycloaddition with furans.
- Marsais, F.,Trecourt, F.,Breant, P.,Queguiner, G.
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- Bromination of Some Pyridine and Diazine N-Oxides
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Selected monosubstituted pyridines, pyrazines, pyrimidines, and their N-oxides, having an electron-donating substituent, were successfully brominated under very mild conditions.The N-oxide function itself is not sufficient to cause these ?-deficient systems to undergo electrophilic aromatic halogenation.Only strongly electron-donating substituents (amino groups) activate the heterocyclic nucleus toward bromination.These substituents direct the electrophilic substitution ortho/para to them with or without the N-oxide group present.Pyridine and diazines with moderately activating substituents such as alkoxy groups are brominated only when their ortho/para activation is augmented by the activation of the N-oxide funtion.Failure to brominate 5-methoxypyrimidine 1-oxide may well reflect the greater ? deficiency of the pyrimidine ring.
- Paudler, William W.,Jovanovic, Misa V.
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p. 1064 - 1069
(2007/10/02)
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- Kinetics and mechanism of the bromination of 4-pyridone and related derivatives in aqueous solution
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The kinetics of bromination of 4-pyridone and selected derivatives have been measured in aqueous solutions in the pH range 0-9, at 25 deg C.The tautomeric system 4-pyridone 4-hydroxypyridine (1a 2a) reacts with bromine via the predominant (pyridone) tautomer at pH 6. 3-Bromo-4-pyridone behaves similary.The kinetics also reveal that the facile dibromination of 4-pyridone occurs because at most pH's the monobromo derivative is actually more reactive towards bromine by virtue of its lower pKa values.From the point of view of reactivity the 4-pyridones and their anions behave as substituted phenoxide ions. 4-Methoxypyridine does not undergo bromination under comparable conditions, but rather forms a complex with bromine.
- Tee, Oswald S.,Paventi, Martino
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p. 2556 - 2562
(2007/10/02)
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