- Aerial oxidation of some 2-pyridyl ketone hydrazones catalyzed by Cu2+. Physical properties of reaction products
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Some 2-pyridyl ketone hydrazones were subjected to aerial oxidation catalyzed by Cu2+. The oxidation product of di-2-pyridyl ketone hydrazone had the structure of a derivative of [1,2,3]-triazolo[1,5-a]pyridine, and this structure is different from that previously proposed by other investigators. The fluorescence spectra of the oxidation products were measured in solutions of a wide pH range. In contrast to the oxidation products of other 2-pyridyl ketone hydrazones, that of di-2-pyridyl ketone hydrazone showed very strong fluorescence in acidic media. The characteristic nature of this compound was also apparent in the ultraviolet spectrum. The generation of hydroxyl radical was demonstrated in the aerial oxidation of di-2-pyridyl ketone hydrazone catalyzed by Cu2+, suggesting the formation of hydrogen peroxide as another oxidation product.
- Mori,Sakamoto,Mashito,Matsuoka,Matsubayashi,Sakai
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- Synthesis of novel triazolopyridylboronic acids and esters. Study of potential application to Suzuki-type reactions
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This paper describes a general method for the synthesis of novel [1,2,3]triazolo[1,5-a]pyridylboronic acids and esters, and the first results on Suzuki cross-coupling reactions with these new compounds and [1,2,3]triazolo[5,1-a]isoquinolylboronic acid, re
- Abarca, Belén,Ballesteros, Rafael,Blanco, Fernando,Bouillon, Alexandre,Collot, Valérie,Domínguez, José-Reynaldo,Lancelot, Jean-Charles,Rault, Sylvain
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- Transannulation of Pyridotriazoles with Naphthoquinones and Indoles: Synthesis of Benzo[f]Pyrido[1,2-a]Indoles and Indolizino[3,2-b]indoles
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Ruthenium catalysed denitrogenative transannulation of pyridotriazoles with naphthoquinones provided the transannulated benzo[f]pyrido[1,2-a]indoles derivatives in good to excellent yields. While pyridotriazoles with indoles in presence of PivOH and oxone yield indolizino[3,2-b]indoles under metal-free conditions. Quinone annulation proceeds through ruthenium-carbenoid intermediate while indole annulation may proceed via a diazo-pyridinium intermediate. Control experiments suggest that both the transformations follow the ionic mechanism. (Figure presented.).
- Rawat, Deepa,Adimurthy, Subbarayappa
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- Nitrous oxide as a diazo transfer reagent: The synthesis of triazolopyridines
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Nitrous oxide is a potential diazo transfer reagent, but its applications in organic chemistry are scarce. Here, we show that triazolopyridines and triazoloquinolines are formed in the reactions of metallated 2-alkylpyridines or 2-alkylquinolines with N2O. The reactions can be performed under mild conditions and give synthetically interesting triazoles in moderate to good yields.
- Landman, Iris R.,Fadaei-Tirani, Farzaneh,Severin, Kay
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supporting information
p. 11537 - 11540
(2021/11/16)
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- Visible-Light-Catalyzed in Situ Denitrogenative Sulfonylation of Sulfonylhydrazones
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A photocatalyzed in situ denitrogenative sulfonylation of N-arylsulfonyl hydrazones has been developed. This transformation provides a low-carbon strategy to assemble arylalkyl sulfones in a stepwise denitrogenation/sulfonylation manner.
- Huang, Xiang,Chen, Xing,Xie, Haisheng,Tan, Zheng,Jiang, Huanfeng,Zeng, Wei
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supporting information
p. 6784 - 6788
(2021/09/08)
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- Triazolopyridazine derivative as well as preparation method, pharmaceutical composition and application thereof
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The invention relates to triazolopyridazine derivatives as well as a preparation method, a pharmaceutical composition and application thereof. The invention provides a compound shown in a general formula (I), cis-trans isomers, enantiomers, diastereoisomers, racemes, solvates, hydrates or pharmaceutically acceptable salts or prodrugs of the compound, and a preparation method of the compound, the cis-trans isomers, the enantiomers, the diastereoisomers, the racemes, the solvates, the hydrates or the pharmaceutically acceptable salts or the prodrugs of the compound; preparation method thereof; pharmaceutical compositions containing the compounds, and the use of the compounds as alpha 5-GABAA receptor modulators, wherein R 1, R 2, and Z are as defined in the specification. pharmaceutical compositions containing the compounds and application of the compounds as alpha-5-GABAA receptor modulators, wherein R1, R2 and Z are as defined in the specification.
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Paragraph 1058-1061
(2021/06/22)
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- Method for synthesizing [1,2,3]triazole[1,5-a]pyridines compound through non-catalyst N-N coupling reaction
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The invention relates to a method for synthesizing [1,2,3]triazole[1,5-a]pyridines compound through non-catalyst N-N coupling reaction. The invention discloses an efficient method for synthesizing a product at one step without using a catalyst under a mild condition from a 2-pyridylamine compound and nitroso tert-butyl ester as a mild nitrogen atom source. The method is free from the catalyst, thereaction step is reduced, the condition is extremely mild, the efficiency is high, and the later modification can be performed on the biological active molecular, thereby facilitating the industrialproduction of [1,2,3]triazole[1,5-a]pyridines compound.
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Paragraph 0032-0037; 0048-0056
(2019/04/04)
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- TBAB-Catalyzed Csp3–N Bond Formation by Coupling Pyridotriazoles with Anilines: A New Route to (2-Pyridyl)alkylamines
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A new metal-free procedure allowing Csp3–N bond formation through coupling of pyridotriazoles and weakly nucleophilic anilines has been developed. This sustainable reaction shows high tolerance towards functional groups (ketones, free alcohols) leading to 2-picolylamine derivatives. The key to our success is the use of a catalytic amount of TBAB and water as a co-solvent leading to the formation of pyridylalkylamine derivatives. As this coupling tolerates the presence of Csp2–Br bond on both partners of the reaction, we performed a sequential one-pot reaction between functionalized triazolopyridines and anilines followed by a second coupling with N-tosylhydrazones leading to the formation of Csp3–N and Csp2–Csp2 bonds.
- Lamaa, Diana,Lin, Hsin-Ping,Bzeih, Tourin,Retailleau, Pascal,Alami, Mouad,Hamze, Abdallah
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supporting information
p. 2602 - 2611
(2019/04/16)
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- Cobalt(II)-based Metalloradical Activation of 2-(Diazomethyl)pyridines for Radical Transannulation and Cyclopropanation
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A new catalytic method for the denitrogenative transannulation/cyclopropanation of in-situ-generated 2-(diazomethyl)pyridines is described using a cobalt-catalyzed radical-activation mechanism. The method takes advantage of the inherent properties of a CoIII-carbene radical intermediate and is the first report of denitrogenative transannulation/cyclopropanation by a radical-activation mechanism, which is supported by various control experiments. The synthetic benefits of the metalloradical approach are showcased with a short total synthesis of (±)-monomorine.
- Roy, Satyajit,Das, Sandip Kumar,Chattopadhyay, Buddhadeb
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supporting information
p. 2238 - 2243
(2018/02/19)
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- Impact and importance of electrostatic potential calculations for predicting structural patterns of hydrogen and halogen bonding
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The way in which differences in electrostatic potential values can govern how ditopic hydrogen/halogen-bond acceptors form supramolecular interactions in the solid state has been examined using two heterocycles, [1,2,3]triazalo-[3,5-α]quinoline and, [1,2,3]triazalo-[3,5-α]pyridine. In general, the better donor (as ranked by electrostatic potential values) preferentially binds to the acceptor atom that carries the higher electrostatic potential value but the outcome is crucially dependent on the magnitude of the potential-energy differences, and structural selectivity can be fine-tuned to generate specifically targeted supramolecular architectures. DFT calculations on [1,2,3]triazalo-[3,5-α]quinoline and [1,2,3]triazalo-[3,5-α]pyridine indicate that the differences in electrostatic potential between the competing sites on the molecules are 38 kJ mol-1 and 26 kJ mol-1, respectively. In order to establish how the nature of the electrostatic potential differences impact the structural landscape around these molecules both heterocycles were co-crystallized with twelve hydrogen-bond (HB) donors, five halogen-bond (XB) donors, and four mixed HB/XB donors. A total of 42 new co-crystals were obtained (as determined by IR spectroscopy), eight of which yielded crystals suitable for single-crystal X-ray diffraction. Results indicate that an electrostatic potential difference greater than 38 kJ mol-1 leads to a pronounced intermolecular preference for the best acceptor but no selectivity is obtained with a smaller difference. This study shows that electrostatic factors play important roles for defining the structural landscape around molecules capable of engaging in a numerous and competing intermolecular interactions as long as the difference between potentially competing sites is large enough.
- Perera,Desper,Sinha,Aaker?y
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p. 8631 - 8636
(2016/11/19)
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- Copper-catalyzed aerobic carboxygenation and N-arylation of [1,2,3]triazolo[1,5-a]pyridines towards pyridinium triazolinone ylides
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Copper-catalyzed aerobic oxyarylation of [1,2,3]triazolo[1,5-a]pyridines is developed. Notably molecular oxygen was utilized as one of the reagents and the transformation resulted in the formation of novel pyridinium triazolinone ylides. A basic mechanism for the one-pot process is proposed and further functionalization of the ylidic products were also presented.
- Pankajakshan, Sreekumar,Chng, Zhi Guang,Ganguly, Rakesh,Loh, Teck Peng
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supporting information
p. 5929 - 5931
(2015/03/30)
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- Facile one-pot synthesis of [1,2,3]triazolo[1,5-a]pyridines from 2-acylpyridines by copper(II)-catalyzed oxidative N-N bond formation
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An efficient and simple method for the synthesis of various [1,2,3]triazolo[1,5-a]pyridines has been established. The method involves a copper(II)-catalyzed oxidative N-N bond formation that uses atmospheric oxygen as the terminal oxidant following hydrazonation in one pot. The use of ethyl acetate as the solvent dramatically promotes the oxidative N-N bond-formation reaction and enables the application of oxidative cyclization in the efficient one-pot reaction. A mechanism for the reaction was proposed on the basis of the results of a spectroscopic study. In the same pot: [1,2,3]Triazolo[1,5-a] pyridines are synthesized from the corresponding 2-acylpyridines by a one-pot method, consisting of hydrazonation followed by oxidative cyclization through copper(II)-catalyzed N-N bond formation (see scheme).
- Hirayama, Tasuku,Ueda, Satoshi,Okada, Takahiro,Tsurue, Norihiko,Okuda, Kensuke,Nagasawa, Hideko
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supporting information
p. 4156 - 4162
(2014/04/17)
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- Ni-catalyzed alkenylation of triazolopyridines: Synthesis of 2,6-disubstituted pyridines
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A synthetic strategy to access 2,6-disubstituted pyridines from triazolopyridines through a regioselective nickel-catalyzed alkenylation reaction of the C7-H bond is described. The N2 fragment embedded in the resulting C-H functionalized triazolopyridine can be readily excised using acidic or oxidative conditions to unmask the pyridine.
- Liu, Sheng,Sawicki, James,Driver, Tom G.
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supporting information; experimental part
p. 3744 - 3747
(2012/08/28)
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- Triazolopyridines. Part 27.1 the preparation of novel 6,7-dihydro[1,2,3] triazolo[1,5-a]pyridines
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A very efficient synthesis of the unknown family of 6,7-dihydro[1,2,3] triazolo[1,5-α]pyridines from [1,2,3]triazolo[1,5-α]pyridines have been developed, and a mechanism for their formation has been proposed. Their behaviour with NBS to give 4,5-dibromo substituted-4,5,6,7-tetrahydro-[1,2,3] triazolo[1,5-α]pyridines is studied.
- Abarca, Belen,Adam, Rosa,Ballesteros, Rafael
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body text
p. 319 - 327
(2010/08/19)
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- Regiospecific solid-phase synthesis of substituted 1,2,3-triazoles
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A traceless and regiospecific solid-phase synthesis of substituted 1,2,3-triazoles is developed using polystyrene-sulfonyl hydrazide resin. The chemistry is applicable to combinatorial library synthesis.
- Raghavendra, Makam S.,Lam, Yulin
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p. 6129 - 6132
(2007/10/03)
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- Hypervalent iodine oxidation of hydrazones of some nitrogen heterocyclic ketones and aldehydes: An efficient synthesis of fused 1,2,3- triazoloheterocycles
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Fused 1,2,3-triazoloheterocycles have been prepared by iodobenzene diacetate mediated oxidation of hydrazones of nitrogen heterocyclic ketones and aldehydes.
- Prakash, Om,Gujral, Harpreet K.,Rani, Neena,Singh, Shiv P.
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p. 417 - 425
(2007/10/03)
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- The Reactions of 1,2,3-Triazolopyridine with Electrophiles
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On treatment with chlorine, bromine, or mercuric acetate triazolopyridine (1) gives dichloromethyl-, dibromomethyl-, and alkoxy(alkoxymercurio)methyl-pyridines (3), (4), (5), and (8) with loss of nitrogen.Nitration gives 3-nitrotriazolopyridine (9), which on reduction gives 3-(2-pyridyl)imidazopyridine (11).The mechanism of formation of these compounds is discussed.
- Jones, Gurnos,Sliskovic, D. Robert,Foster, Beverley,Rogers, John,Smith, Anthony K.,et al.
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