- Recyclable Heterogeneous Copper(II)-Catalyzed Oxidative Cyclization of 2-Pyridine Ketone Hydrazones towards [1,2,3]Triazolo[1,5-a]pyridines
-
The heterogeneous copper(II)-catalyzed oxidative cyclization of 2-pyridine ketone hydrazones was achieved in ethyl acetate at room temperature in the presence of an MCM-41-anchored bidentate 2-aminoethylamino copper(II) catalyst [MCM-41-2N-Cu(OAc) 2
- Cai, Mingzhong,Jiang, Gan,Lin, Yang,Zhao, Hong
-
p. 4487 - 4497
(2019/11/21)
-
- TBAB-Catalyzed Csp3–N Bond Formation by Coupling Pyridotriazoles with Anilines: A New Route to (2-Pyridyl)alkylamines
-
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
-
supporting information
p. 2602 - 2611
(2019/04/16)
-
- Safe and Facile Access to Nonstabilized Diazoalkanes Using Continuous Flow Technology
-
Despite the high synthetic potential of nonstabilized diazo compounds, their utilization has always been hampered by stability, toxicity, and safety issues. The present method opens up access to the most reactive nonstabilized diazoalkanes. Among diazo compounds, nonstabilized alkyl diazo compounds are the least represented because of their propensity to degrade during preparation. The continuous flow oxidation process of hydrazones on a silver oxide column afforded an output stream of base- and metal-free pure diazo solution in dichloromethane. Starting from innocuous ketones and aldehydes, this methodology allows the production of a broad range of unprecedented diazoalkanes compounds in excellent yields, while highlighting their synthetic potential and the possibility of safe large-scale diazo production.
- Rullière, Pauline,Benoit, Guillaume,Allouche, Emmanuelle M. D.,Charette, André B.
-
supporting information
p. 5777 - 5782
(2018/05/14)
-
- Palladium-Catalyzed Divergent Arylation with Triazolopyridines: One-Pot Synthesis of 6-Aryl-2-α-styrylpyridines
-
We have developed a new strategy for palladium-catalyzed arylation reactions with triazolopyridines, wherein two different chemical transformations (C-3 vs. C-7) are observed by differentiating the substrates using different bases. The reactive palladium carbenoids were directly generated from triazolopyridines and underwent denitrogenative arylations with aryl bromides. Intriguingly, when potassium carbonate was replaced with potassium tert-butoxide, direct C-H arylation occurred at the most acidic position (C-7). Moreover, two different catalytic arylation events were successfully performed in a one-pot sequence, providing a convenient access to 6-aryl-2-α-styrylpyridines.
- Moon, Youngtaek,Kwon, Soonhyung,Kang, Dahye,Im, Honggu,Hong, Sungwoo
-
supporting information
p. 958 - 964
(2016/04/05)
-
- Rhodium-catalyzed NH insertion of pyridyl carbenes derived from pyridotriazoles: A general and efficient approach to 2-picolylamines and imidazo[1,5-a]pyridines
-
A general and efficient NH insertion reaction of rhodium pyridyl carbenes derived from pyridotriazoles was developed. Various NH-containing compounds, including amides, anilines, enamines, and aliphatic amines, smoothly underwent the NH insertion reaction to afford 2-picolylamine derivatives. The developed transformation was further utilized in a facile one-pot synthesis of imidazo[1,5-a]pyridines.
- Shi, Yi,Gulevich, Anton V.,Gevorgyan, Vladimir
-
supporting information
p. 14191 - 14195
(2015/01/09)
-
- 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
-
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
-
supporting information
p. 4156 - 4162
(2014/04/17)
-
- Ni-catalyzed alkenylation of triazolopyridines: Synthesis of 2,6-disubstituted pyridines
-
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.
-
supporting information; experimental part
p. 3744 - 3747
(2012/08/28)
-
- Triazolopyridines. Part 29. Direct arylation reactions with [1,2,3]triazolo[1,5-a]pyridines
-
[1,2,3]Triazolo[1,5-a]pyridine reacts with aryl halides in presence of catalytic amounts of Pd(OAc)2 and PPh3 in DMF to give, in medium or low yield, direct arylations in C3 and pyridyl aryl ketones. Thiazole and benzothiazole have been directly arylated using 7-halotriazolopyridines. These behaviours are unprecedented in the chemistry of [1,2,3]triazolo[1,5-a] pyridines. ARKAT-USA, Inc.
- Abarca, Belen,Adam, Rosa,Ballesteros, Rafael,Chiassai, Leonardo,Gamon, Cristina
-
p. 229 - 241
(2013/02/25)
-
- Synthesis of novel triazolopyridylboronic acids and esters. Study of potential application to Suzuki-type reactions
-
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
-
p. 4887 - 4893
(2007/10/03)
-
- Regiospecific solid-phase synthesis of substituted 1,2,3-triazoles
-
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
-
p. 6129 - 6132
(2007/10/03)
-
- Hydroperoxide oxidation of azomethines and alkylarenes catalyzed by ebselen
-
2-Phenyl-1,2-benzisoselenazol-3(2H)-one (ebselen), known as glutathione peroxidase mimic, is found as an efficient catalyst for hydrogen peroxide and tert-butyl hydroperoxide oxidation of the azomethine group in azines, aldoximes, and methyl or methylene group in alkylarenes. Depending on the substrate used and the reaction conditions, the major products are aldehydes, ketones, carboxylic acids or their derivatives. It is postulated that ebselen is involved in the free-radical oxidation mechanism.
- Giurg,Wojtowicz,Mlochowski
-
p. 537 - 542
(2007/10/03)
-
- Hypervalent iodine oxidation of hydrazones of some nitrogen heterocyclic ketones and aldehydes: An efficient synthesis of fused 1,2,3- triazoloheterocycles
-
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.
-
p. 417 - 425
(2007/10/03)
-
- Synthesis and reactions of 1-azo-2-azoniaallene salts derived from pyridine derivatives
-
The 1-aza-2-azonia-allene salts prepared from 3-acetyl- or 3-benzoyl-pyridine via the corresponding hydrazone and α-chloroaryl-azo derivatives react with propionitrile to afford the corresponding 3-(3-pyridyl)-1,2,4-triazolium salts. The intramolecular cy
- Amer, Atef M.
-
p. 1293 - 1303
(2007/10/03)
-
- Aerial oxidation of some 2-pyridyl ketone hydrazones catalyzed by Cu2+. Physical properties of reaction products
-
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
-
p. 1944 - 1947
(2007/10/02)
-
- TRIAZOLOPYRIDINES. 15. REACTIONS BETWEEN TRIAZOLO-PYRIDINIUM YLIDES AND ALKENES
-
The triazolopyridine ylides (1) react with acrylates (2) to give 3-(2-pyridyl)acrylates (4a) and (4b), the 2-pyridylcyclobutanes (5a)-(5g), the pyridylpent-1-ene (8) and the zwitterion (3.) The mechanism of reaction between the ylides (1) and acrylates or alkynes is discussed.
- Abacra, Belen,Ballesteros, Rafael
-
p. 851 - 862
(2007/10/02)
-
- Triazolopyridines. Part 11. Ylides derived from 2-acylmethyltriazolopyridinium salts
-
Ylides derived from 2-acylmethyltriazolopyridinium salts (2a) -(2c) react with methyl or ethyl propiolate and with dimethyl acetylenedicarboxylate to give ylides (3a)-(3e), (6) or (7). In some cases 1:2 adducts are formed, shown to be the novel ylides (8a)-(8d); an X-ray diffraction confirms structure (8a).
- Abarca, Belen,Ballesteros, Rafael,Mojarrad, Fatemeh,Metni, Mohamed R.,Garcia-Granda, Santiago,Perez-Carreno, Enrique,Jones, Gumos
-
p. 5277 - 5286
(2007/10/02)
-
- Triazolopyridines. Part 7. Preparation of Bromo-triazolopyridines and-triazoloisoquinolines
-
Bromination of the 7-lithiotriazolopyridines (7) and (10) gave small yields of the 7-bromotriazolopyridines (8) and (11).Some ring opening was observed with the lithium derivative (7); ring opening was a major reaction when bromine reacted with 5-lithiotriazoloisoquinoline (15) or with the 7-trimethylsilyltriazolopyridine (20).Good yields of 7-bromotriazolopyridines (8) and (18) and of 5-bromotriazoloisoquinoline (19) were obtained from the appropriate lithio derivative and dibromotetrachloroethane.The properties of 5-trimethylsilyltriazoloisoquinoline and its lithium derivative are reported; protodesilylation has been achieved with compounds (25)-(28).
- Abarca, Belen,Ballesteros, Rafael,Mojarred, Fatemeh,Jones, Gurnos,Mouat, Deborah J.
-
p. 1865 - 1868
(2007/10/02)
-