- Bu4NI-Catalyzed, Radical-Induced Regioselective N-Alkylations and Arylations of Tetrazoles Using Organic Peroxides/Peresters
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Bu4NI-catalyzed regioselective N2-methylation, N2-Alkylation, and N2-Arylation of tetrazoles have been achieved using tert-butyl hydroperoxide (TBHP) as the methyl source, alkyl diacyl peroxides as the primary alkyl source, alkyl peresters as the secondary and tertiary alkyl sources, and aryl diacyl peroxides as the arylating source. These reactions proceed without pre-functionalization of tetrazole and in the absence of any metal catalysts. Here, peroxides serve the dual role of oxidants as well as alkylating or arylating agents. Based on DFT calculations, it was found that spin density, transition-state barriers (kinetic control), and thermodynamic stability of the products (thermodynamic control) play essential roles in the observed regioselectivity during N-Alkylation. This radical-mediated process is amenable to a broad range of substrates and provides products in moderate to good yields.
- Ghosh, Subhendu,Mir, Bilal Ahmad,Patel, Bhisma K.,Rajamanickam, Suresh,Sah, Chitranjan,Sethi, Garima,Venkataramani, Sugumar,Yadav, Vinita
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p. 2118 - 2141
(2020/03/13)
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- Light-Induced Tetrazole-Quinone 1,3-Dipolar Cycloadditions
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Quinones were firstly used as dipolarophiles in a photoclick 1,3-cycloaddition with 2,5-diaryltetrazoles, as photoactivatable predipoles, providing a novel and efficient access to three types of pyrazole-fused quinones (indazoledione derivatives). Distinc
- Ortiz-Rojano, Laura,Rojas-Martín, Jaime,Rodríguez-Diaz, Ciro,Carre?o, M. Carmen,Ribagorda, Maria
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p. 15050 - 15054
(2019/11/13)
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- 5-substituted-2-2H-tetrazoleamine manufacturing method
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The present invention is a method for producing a 5-substituted-2-aryl-2H-tetrazole that is useful as an intermediate for producing a pharmaceutical compound, and relates to a method which selectively introduces an aryl group in the 2 position.
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Paragraph 0041-0043; 0057
(2021/09/18)
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- The development of copper-catalyzed aerobic oxidative coupling of h-tetrazoles with boronic acids and an insight into the reaction mechanism
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The development of a highly efficient and practical protocol for the direct C-N coupling of H-tetrazole and boronic acid was presented. A careful and patient optimization of a variety of reaction parameters revealed that this conventionally challenge reaction could indeed proceed efficiently in a very simple system, that is, just by stirring the tetrazoles and boronic acids under oxygen in the presence of different CuI or CuII salts with only 5 mol % loading in DMSO at 100 °C. Most significantly, the reaction could proceed very smoothly in a regiospecific manner to afford the 2,5-disubstituted tetrazoles in high to excellent yields. A mechanistic study revealed that both tetrazole and DMSO are crucial for the generation of catalytically active copper species in the reaction process in addition to their role as reactant and solvent, respectively. It is demonstrated that in the reaction cycle, the CuI catalyst could be oxidized to CuII by oxygen to form a [CuT2D] complex (T=tetrazole anion; D=DMSO) through an oxidative copper amination reaction. The CuII complex thus formed was confirmed to be the real catalytically active copper species. Namely, the CuII complex disproportionates to aryl CuIII and CuI in the presence of boronic acid. Facile elimination of the CuIII species delivers the C-N-coupled product. The results presented herein not only provide a reliable and efficient protocol for the synthesis of 2,5-disubstituted tetrazoles, but most importantly, the mechanistic results would have broad implications for the de novo design and development of new methods for Cu-catalyzed coupling reactions. Copyright
- Liu, Chao-You,Li, Yu,Ding, Jin-Ying,Dong, De-Wen,Han, Fu-She
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supporting information
p. 2373 - 2381
(2014/03/21)
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- Efficient synthesis of 2,5-disubstituted tetrazoles via the Cu 2O-catalyzed aerobic oxidative direct cross-coupling of N-H free tetrazoles with boronic acids
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We present a new protocol that allows for the synthesis of 2,5-disubstituted tetrazoles via the direct coupling of N-H free tetrazoles and low toxic boronic acids in the presence of only a catalytic amount of Cu 2O (5 mol%) as catalyst and 1 atm of environmentally benign O 2 as oxidant, without the need for other additives. This method represents a simple, green, and atom-efficient synthesis of 2,5-disubstituted tetrazoles. The Royal Society of Chemistry 2012.
- Li, Yu,Gao, Lian-Xun,Han, Fu-She
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supporting information; experimental part
p. 2719 - 2721
(2012/03/27)
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- A ceric ammonium nitrate N-dearylation of N-p-anisylazoles applied to pyrazole, triazole, tetrazole, and pentazole rings: Release of parent azoles. Generation of unstable pentazole, HN5/N5-, in solution
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(Chemical Equation Presented) The reaction of cerium(IV) ammonium nitrate (CAN) with a range of N-(p-anisyl)azoles in acetonitrile or methanol solvents leads to N-dearylation releasing the parent NH-azole and p-benzoquinone in comparable yields. The scope and limitations of the reaction are explored. It was successful with 1-(p-anisyl)pyrazoles, 2-(p-anisyl)-1,2,3-triazoles, 2-(p-anisyl)-2H-tetrazoles, and 1-(p-anisyl)pentazole. The dearylation renders the p-anisyl group as a potentially useful N-protecting group in azole chemistry. The azole released in solution from 1-(p-anisyl)pentazole is unstable HN5, the long-sought parent pentazolic acid. p-Anisylpentazole samples were synthesized with combinations of one, two, and three 15N atoms at all positions of the pentazole ring. The unstable HN 5/N5- produced at -40°C did not build up in the solution but degraded to azide ion and nitrogen gas with a short lifetime. The 15N-labeling of the N3- ion obtained from all samples proved unequivocally that it came from the degradation of HN 5 (tautomeric forms) and/or its anion N5- in the solution.
- Butler, Richard N.,Hanniffy, John M.,Stephens, John C.,Burke, Luke A.
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p. 1354 - 1364
(2008/04/12)
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- Heterocyclic derivatives of fullerene C60. 1. Synthesis of new fulleropyrazolines by the 1,3-dipolar cycloaddition of nitrile imines
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New stable [6,6]-closed cycloadducts, fulleropyrazolines containing aryl, hetaryl, trifluoromethyl, and other substituents in the five-membered ring, have been obtained by the 1,3-dipolar cycloaddition of nitrile imines to C 60. Two methods of generating nitrile imines in situ have been used, the dehydrohalogenation of the corresponding hydrazonoyl halides by the action of triethylamine and the thermal decomposition of 2,5-diaryltetrazoles.
- Reinov,Yurovskaya,Davydov,Streletskii
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p. 188 - 193
(2007/10/03)
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- Palladium- and copper-catalyzed selective arylation of 5-aryltetrazoles by diaryliodonium salts
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Palladium(0)-catalyzed arylation of 5-aryltetrazoles in t-BuOH at 80°C with diaryliodonium salts proceeds in the presence of copper(II) phenylcyclopropyl carboxylate regioselectively at the N2 position.
- Beletskaya, Irina P.,Davydov, Dmitri V.,Gorovoy, Matvey S.
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p. 6221 - 6223
(2007/10/03)
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