77896-39-0Relevant articles and documents
Molybdenum-Catalyzed Deoxygenation of Heteroaromatic N-Oxides and Hydroxides using Pinacol as Reducing Agent
Rubio-Presa, Rubén,Fernández-Rodríguez, Manuel A.,Pedrosa, María R.,Arnáiz, Francisco J.,Sanz, Roberto
, p. 1752 - 1757 (2017/05/22)
A molybdenum-catalyzed deoxygenation of pyridine N-oxides and N-hydroxybenzotriazoles, as well as other azole N-oxides, has been developed using pinacol as an environmentally friendly oxo-acceptor. The only by-products are acetone and water making the process a convenient alternative to established protocols in terms of waste generation. The reaction is highly chemoselective and a variety of functional groups are tolerated. The processes are usually very clean allowing the isolation of the pure deoxygenated products after a simple extraction in most cases. (Figure presented.).
Room-temperature oxidative Suzuki coupling reaction of 1,2,3-triazole N-oxides
Liu, Wei,Yu, Yanyan,Fan, Boyi,Kuang, Chunxiang
, p. 2969 - 2971 (2017/07/10)
This study develops a new efficient pathway for synthesis of 2,4-disubstituted 1,2,3-triazoles through regioselective direct arylation between 2-aryl-1,2,3-triazole N-oxides and Ar-B(OH)2. The reaction proceeds smoothly at room temperature and exhibits good yield and high C5 position selectivity. The possible pathway of oxidative Suzuki coupling is also discussed. This simple methodology can be used to construct 2,4-disubstituted 1,2,3-triazole moiety.
2,2′-Homocoupled Azine N,N′-Dioxides or Azine N-Oxides: CDC- or SNAr-Controlled Chemoselectivity
Jha, Abadh Kishor,Jain, Nidhi
, p. 4765 - 4772 (2017/09/07)
An unprecedented Cu(OAc)2- and LiOtBu-mediated homocoupling of azine N-oxides to yield 2,2′-azine N,N′-dioxides is reported. This is the first instance in which copper has been used to catalyze the homodimerization reaction, especially of 2-phenylpyridine N-oxides. In the absence of catalytic copper, the reaction follows an alternative pathway, and instead of dioxides it yields 2,2′-azine N-monoxides. This latter protocol works efficiently with a range of N-heterocyclic oxides of pyridine, 2-phenylpyridine, quinoline and N-aryl-1,2,3-triazole. It is scalable, offers high regioselectivity and gives the products in moderate to high yields. The observed chemoselectivity between the copper-assisted and copper-free protocols is routed through oxidative cross-dehydrogenative coupling (CDC) and nucleophilic aromatic substitution of hydrogen (SNAr) pathways, respectively.
Iridium(III)-Catalyzed Direct C-H Sulfonamidation of 2-Aryl-1,2,3-triazole N-Oxides with Sulfonyl Azides
Zhu, Bingfeng,Cui, Xiuling,Pi, Chao,Chen, Dong,Wu, Yangjie
, p. 326 - 332 (2016/02/14)
We have developed a method for the direct sulfonamidation of 2-aryl-1,2,3-triazole N-oxides using sulfonyl azides as the amino source to release molecular nitrogen as the sole by-product. This protocol exhibits excellent functional group tolerance and proceeds efficiently under external oxidant-free conditions. Various 2-(2-sulfonamidoaryl)-1,2,3-triazoles were prepared in up to 97% yields for 25 examples with excellent regioselectivity.
Site-selective direct arylation of 1,2,3-triazole N-oxides
Liu, Wei,Li, Yahui,Wang, Yue,Kuang, Chunxiang
, p. 5272 - 5275 (2013/09/02)
An efficient route for the synthesis of 2,4-disubstituted 1,2,3-triazoles by the regioselective direct arylation of 2-aryl-1,2,3-triazole N-oxides with Ar-X [X = Br, I and B(OH)2] is demonstrated. The reaction proceeds through Pd-catalyzed C-H bond activation, and the influence of the aryl halides on the reactivity is investigated. An efficient route for the synthesis of 2,4-disubstituted 1,2,3-triazoles by the regioselective direct arylation of 2-aryl-1,2,3-triazole N-oxides with Ar-X [X = Br, I and B(OH)2] is demonstrated. The reaction proceeds through Pd-catalyzed C-H bond activation, and the influence of the aryl halides on the reactivity is investigated. Copyright
Addition of Nitrite Ions to 1-Methoxy-1,2,3-triazolium Salts. Formation of Nitro and Hydroxy Substituted Triazoles
Begtrup, Mikael,Knudsen, Niels Ole
, p. 97 - 100 (2007/10/02)
Potassium and silver nitrite add to 1-methoxy-2-phenyltriazolium salts as ambident nucleophiles to give 4-nitro- and 4-hydroxytriazoles.If unsubstituted, the latter, via nitrosation and oxidation, affords 4-hydroxy-5-nitro-2-phenyltriazole.The hydroxytriazoles add to unchanged starting material producing bistriazolyl ethers.A nitro-substituted derivative of the latter displays photochromic properties.
Electrophilic and Nucleophilic Substitution in the Triazole N-Oxides and N-Methoxytriazolium Salts: Preparation of Substituted 1,2,3-Triazoles
Begtrup, Mikael,Holm, John
, p. 503 - 513 (2007/10/02)
2-Phenyltriazole 1-oxides are activated at C-5 towards both electrophilic and nucleophilic attack.The N-oxides can be selectively halogenated and, in turn, the halogen replaced by strong nucleophiles.On subsequent deoxygenation, the N-oxides yield halogeno-, methylthio-, and methoxy-triazoles.Methylation produces N-methoxytriazolium salts in which H-5 can be replaced by weak nucleophiles, e.g. fluoride ions.Thus fluoro-, chloro-, hydroxy-, alkoxy-, acyloxy-, amino-, substituted amino-, azido-, nitro-, mercapto-, alkylthio-, acylthio-, and cyano-substituents can be introduced in the triazole nucleus.Alternatively deprotonated N-methoxytriazolium salts react with electrophiles producing substituted triazole N-oxides.The reactions of triazole N-oxides with hydrogen chloride to give chlorotriazoles, and with acetyl chloride to give acetoxytriazoles, are explained.
