- Aluminum(III) hydrogensulfate: An efficient solid acid catalyst for the preparation of 5-substituted 1H-tetrazoles
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An efficient method for preparation of 5-substituted 1H-tetrazoles via [2+3] cycloaddition of nitriles and sodium azide is reported using aluminum(III) hydrogensulfate as an effective solid acid. This method has the advantages of good yields, simple methodology, and easy workup. Copyright
- Sajadi, S. Mohammad,Khalaj, Mehdi,Jamkarani, Sayyed Mohammad Hosseini,Maham, Mehdi,Kashefib, Mehrdad
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- Highly efficient synthesis of 1- and 5-substituted 1H-tetrazoles using chitosan derived magnetic ionic liquid as a recyclable biopolymer-supported catalyst
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A general method for the efficient synthesis of 1- and 5-substituted 1H-tetrazoles from nitriles and amines is described using chitosan supported magnetic ionic liquid nanoparticles (CSMIL) as a novel heterogeneous catalyst. The application of this catalyst allows the synthesis of a variety of tetrazoles in high yields at low temperature. This new magnetic catalyst has been prepared from chitosan (the most abundant biopolymer in nature and cheap industrial waste) and methyl imidazole (a widely available backbone of ionic liquids) which was reacted with FeCl3 to obtain the CS-EMImFeCl4 catalyst. This methodology illustrates a very simple procedure, with wide applicability, environmental friendliness and reusability of catalyst. The new catalyst was characterized using some different microscopic and spectroscopic techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), FTIR spectroscopy, and Raman spectroscopy. The novel catalyst has therefore a great potential to be used in green processes. The Royal Society of Chemistry 2013.
- Khalafi-Nezhad, Ali,Mohammadi, Somayeh
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- The microwave-assisted synthesis of 5-substituted 1: H -tetrazoles via [3+2] cycloaddition over a heterogeneous Cu-based catalyst: Application to the preparation of 13N-labelled tetrazoles
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The [3+2] cycloaddition between various nitriles and sodium azide proceeds smoothly in the presence of a new CuII catalyst in N-methyl-2-pyrrolidone (NMP) to give the corresponding 5-substituted 1H-tetrazoles. The desired tetrazoles were obtain
- Joshi, Sameer M.,Mane, Rasika B.,Pulagam, Krishna R.,Gomez-Vallejo, Vanessa,Llop, Jordi,Rode, Chandrashekhar
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- FeCl3-SiO2 as a reusable heterogeneous catalyst for the synthesis of 5-substituted 1H-tetrazoles via [2+3] cycloaddition of nitriles and sodium azide
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An efficient method for the preparation of 5-substituted 1H-tetrazole derivatives is reported using FeCl3-SiO2 as an effective heterogeneous catalyst. This method has the advantages of high yields, simple methodology, and easy work-up. The catalyst can be recovered by simple filtration and reused delivering good yields.
- Nasrollahzadeh, Mahmoud,Bayat, Yadollah,Habibi, Davood,Moshaee, Saeed
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- Amberlyst-15 catalyzed synthesis of 5-substituted 1-H-tetrazole via [3+2] cycloaddition of nitriles and sodium azide
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A mild and efficient method for the preparation of 5-substituted 1-H-tetrazole derivatives is reported using solid acidic resin Amberlyst-15 as an effective heterogeneous catalyst. This method is advantageous because of non-toxicity and stability of catalyst, high product yield, simple methodology, and easy work up. The catalyst was recovered by simple filtration and reused several times delivering moderate to good product yield.
- Shelkar, Radheshyam,Singh, Abhilash,Nagarkar, Jayashree
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- Nanocrystalline ZnO as an efficient heterogeneous catalyst for the synthesis of 5-substituted 1H-tetrazoles
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Nanocrystalline ZnO is an effective heterogeneous catalyst for the [2 + 3]-cycloaddition of sodium azide with nitriles to afford 5-substituted 1H-tetrazoles in good yields.
- Lakshmi Kantam,Shiva Kumar,Sridhar
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- An experimental and computational assessment of acid-catalyzed azide-nitrile cycloadditions
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The mechanism of the azidea-nitrile cycloaddition mediated by different Bronsted and Lewis acids has been addressed through DFT calculations. In all cases activation of the nitrile substrate by the Bronsted or Lewis acid catalyst was found to be responsib
- Cantillo, David,Gutmann, Bernhard,Kappe, C. Oliver
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- Lithiation Substitution of Unprotected Benzyltetrazoles
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1H-Tetrazoles occupy an important role in modern medicinal chemistry, but few methods for their modification exist. Many extant protocols require the use of a difficult to remove N-alkyl-protecting group, precluding the products from use as carboxylate bioisosteres, the major role of tetrazoles in pharmaceuticals. We herein report a convenient, protecting-group-free lithiation-substitution protocol for benzylic tetrazoles. Metalation with n-BuLi at 0 °C followed by electrophilic trapping gave a range of α-functionalized benzyltetrazoles in up to 91% yield.
- Wong, Jeff Y. F.,Lewandowska, Agnieszka,Trowse, Benjamin R.,Barker, Graeme
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p. 7069 - 7072
(2019/09/30)
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- Synthesis, molecular docking and xanthine oxidase inhibitory activity of 5-aryl-1H-tetrazoles
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5-Aryl-1H-tetrazoles (1–24) were synthesized and screened for their xanthine oxidase (XO) inhibitory activity using allopurinol as standard inhibitor (IC50 = 2.0 ± 0.01 μM). Six compounds 3, 4, 5, 9, 21, and 24 exhibited significant to weak act
- Fatima, Itrat,Zafar, Humaira,Khan, Khalid Mohammed,Saad, Syed Muhammad,Javaid, Sumaira,Perveen, Shahnaz,Choudhary, M. Iqbal
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p. 201 - 211
(2018/05/24)
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- L -Proline: An Efficient Organocatalyst for the Synthesis of 5-Substituted 1 H -Tetrazoles via [3+2] Cycloaddition of Nitriles and Sodium Azide
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A simple and efficient route for the synthesis of a series of 5-substituted 1 H -tetrazoles using l -proline as a catalyst from structurally diverse organic nitriles and sodium azide is reported. The prominent features of this environmentally benign, cost effective, and high-yielding l -proline-catalyzed protocol includes simple experimental procedure, short reaction time, simple workup, and excellent yields making it a safer and economical alternative to hazardous Lewis acid catalyzed methods. The protocol was successfully applied to a broad range of substrates, including aliphatic and aryl nitriles, organic thiocyanates, and cyanamides.
- Bhagat, Saket B.,Telvekar, Vikas N.
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supporting information
p. 874 - 879
(2018/02/16)
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- Choline chloride–ZnCl2: Recyclable and efficient deep eutectic solvent for the [2+3] cycloaddition reaction of organic nitriles with sodium azide
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Herein we report first time choline chloride–zinc chloride based deep eutectic solvent is a green and efficient reaction medium for the [2+3] cycloaddition reaction of organic nitriles with sodium azide to afford the corresponding 5-substituted 1H-tetrazo
- Padvi, Swapnil A.,Dalal, Dipak S.
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supporting information
p. 779 - 787
(2017/04/06)
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- A comparative study between heterogeneous stannous chloride loaded silica nanoparticles and a homogeneous stannous chloride catalyst in the synthesis of 5-substituted 1: H -tetrazole
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Heterogeneous SnCl2-nano-SiO2 efficiently catalyzed 5-substituted 1H-tetrazole synthesis with excellent yield. The catalyst was characterized by using FT-IR, TGA, TEM, and EDX. It is widely applicable on aliphatic, aromatic, heteroaromatic and sterically hindered nitriles with five time recyclability. Being simple and an economically viable approach for the synthesis of SnCl2-nano-SiO2 are additional advantages.
- Kumar, Arvind,Kumar, Satyanand,Khajuria, Yugal,Awasthi, Satish Kumar
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p. 75227 - 75233
(2016/08/24)
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- An efficient and economical synthesis of 5-substituted 1 H -tetrazoles via Pb(II) salt catalyzed [3+2] cycloaddition of nitriles and sodium azide
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A simple, mild and efficient method is developed for the synthesis of 5-substituted 1H-tetrazoles. Out of three used Pb(II) catalysts, lead chloride (PbCl2) has been found to be an efficient catalyst for [3+2] cycloaddition of NaN3 with aromatic and aliphatic nitriles to afford 5-substituted 1H-tetrazoles. The catalyst is reusable up to four cycles with consistent activity. The cost effectiveness and easy availability of the catalyst, simple methodology, excellent yield and easy work-up are the additional advantages.
- Kant, Rama,Singh, Vishal,Agarwal, Alka
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p. 305 - 312
(2016/04/20)
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- OSU-6: A highly efficient, metal-free, heterogeneous catalyst for the click synthesis of 5-benzyl and 5-aryl-1H-tetrazoles
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OSU-6, an MCM-41 type hexagonal mesoporous silica with mild Br?nsted acid properties, has been used as an efficient, metal-free, heterogeneous catalyst for the click synthesis of 5-benzyl and 5-aryl-1H-tetrazoles from nitriles in DMF at 90 °C. This catalyst offers advantages including ease of operation, milder conditions, high yields, and reusability. Studies are presented that demonstrate the robust nature of the catalyst under the optimized reaction conditions. OSU-6 promotes the 1,3-dipolar addition of azides to nitriles without significant degradation or clogging of the nanoporous structure. The catalyst can be reused up to five times without a significant reduction in yield, and it does not require treatment with acid between reactions.
- Nammalwar, Baskar,Muddala, Nagendra Prasad,Pitchimani, Rajasekar,Bunce, Richard A.
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p. 22757 - 22766
(2016/01/25)
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- Synthetic application of gold nanoparticles and auric chloride for the synthesis of 5-substituted 1H-tetrazoles
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An effective one-pot, convenient gold catalyzed synthesis of 5-substituted 1H-tetrazoles has been discussed. The study demonstrated the comparative overview for utilization of gold(iii) and gold nano-particles (spheres) as a catalyst. Detailed understandi
- Kumar, Satyanand,Kumar, Arvind,Agarwal, Alka,Awasthi, Satish Kumar
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p. 21651 - 21658
(2015/03/30)
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- (NH4)2Ce(NO3)6 as an inexpensive, eco-friendly, efficient catalyst for the synthesis of 5-substituted 1-H tetrazoles from nitriles
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Ceric ammonium nitrate (CAN) is found to be a suitable, inexpensive, and effective non-toxic catalyst for a smooth (3+2) cycloaddition of organic nitriles with NaN3 to afford 5-substituted 1H-tetrazoles in excellent yields. Shorter reaction times, easy work-up, and substantial and pure product formation are the key advantages of the present method.
- Kumar, Satyanand,Dubey, Shristy,Saxena, Nisha,Awasthi, Satish Kumar
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p. 6034 - 6038
(2015/01/08)
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- Synthesis of 5-substituted 1H-tetrazoles catalyzed by ceric ammonium nitrate supported HY-zeolite
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In this Letter we wish to report a simple and efficient synthetic protocol for the synthesis of 5-substituted 1H-tetrazole derivatives through the [2+3] cycloaddition of nitriles with sodium azide using ceric ammonium nitrate supported HY-zeolite as a novel catalyst. Excellent yields of the corresponding tetrazoles were obtained through this cost-effective protocol under aerobic conditions with shorter reaction time under mild reaction conditions.
- Sivaguru, Paramasivam,Bhuvaneswari, Kaliyan,Ramkumar, Rangasamy,Lalitha, Appaswami
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supporting information
p. 5683 - 5686
(2014/12/12)
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- β-Cyclodextrin-mediated highly efficient [2+3] cycloaddition reactions for the synthesis of 5-substituted 1H-tetrazoles
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A β-cyclodextrin-promoted [2+3] cycloaddition reaction between nitriles and sodium azide in the presence of ammonium chloride in DMF at 120 °C is reported, affording various 5-substituted 1H-tetrazoles in good to excellent yields in short reaction times. The presence of β-CD renders the formation of a precipitate-like gel in the reaction media when heated. No precipitation occurs in the absence of NaN3 and NH4Cl. The precipitation responses with other salts such as LiCl and NiCl2 were weaker than with NH4Cl. In the present paper the application of supramolecular aggregates is reported for the [2+3] cycloaddition reaction. β-Cyclodextrin can be recovered and reused without any significant loss of activity.
- Patil, Dipak R.,Wagh, Yogesh B.,Ingole, Pravin G.,Singh, Kripal,Dalal, Dipak S.
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p. 3261 - 3266
(2013/10/01)
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- Ammonium acetate mediated synthesis of 5-substituted 1H-tetrazoles
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Synthesis of 5-substituted 1H-tetrazoles was achieved by [3+2] cycloaddition of nitriles and sodium azide in the presence of ammonium acetate. The reaction proceeds in situ formation of ammonium azide. Present protocol has advantage of good to excellent yields, short reaction times and simple isolation of products than reported methods. Iranian Chemical Society 2012.
- Patil, Dipak R.,Deshmukh, Mukesh B.,Dalal, Dipak S.
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p. 799 - 803
(2013/02/22)
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- Mechanistic insights on azide-nitrile cycloadditions: On the dialkyltin oxide-trimethylsilyl azide route and a new vilsmeier-haack-type organocatalyst
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The mechanism of the azide-nitrile cycloaddition mediated by the known dialkylltin oxide-trimethylsilyl azide catalyst system has been addressed through DFT calculations. The catalytic cycle for this tin/silicon complex-based mechanism has been thoroughly examined, disclosing the most plausible intermediates and the energetics involved in the rate enhancement. In addition, a new catalyst, 5-azido-1-methyl-3,4-dihydro-2H-pyrrolium azide, is presented for the formation of tetrazoles by cycloaddition of sodium azide with organic nitriles under neutral conditions. The efficiency of this organocatalyst, generated in situ from N-methyl-2-pyrrolidone (NMP), sodium azide, and trimethylsilyl chloride under reaction conditions, has been examined by preparation of a series of 5-substituted-1H-tetrazoles. The desired target structures were obtained in high yields within 15-25 min employing controlled microwave heating. An in depth computational analysis of the proposed catalytic cycle has also been addressed to understand the nature of the rate acceleration. The computed energy barriers have been compared to the dialkylltin oxide-trimethylsilyl azide metal-based catalyst system. Both the tin/silicon species and the new organocatalyst accelerate the azide-nitrile coupling by activating the nitrile substrate. As compared to the dialkylltin oxide-trimethylsilyl azide method, the organocatalytic system presented herein has the advantage of higher reactivity, in situ generation from inexpensive materials, and low toxicity.
- Cantillo, David,Gutmann, Bernhard,Kappe, C. Oliver
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experimental part
p. 4465 - 4475
(2011/05/14)
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- Montmorillonite K-10 clay as an efficient reusable heterogeneous catalyst for the solvent-free microwave mediated synthesis of 5-substituted 1H-tetrazoles
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Various 5-substituted 1H-tetrazole derivatives were synthesized in a simple and environmentally benign method from the reaction of aryl and benzyl nitriles with sodium azide in solvent-free media using montmorillonite K-10 clay as solid recyclable heterogeneous acidic catalyst and microwave irradiation in good yields and short reaction times. Copyright
- Marvi, Omid,Alizadeh, Abdolhamid,Zarrabi, Saeid
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experimental part
p. 4001 - 4004
(2012/04/10)
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- Synthesis of 5-substituted lH-tetrazoles from nitriles and hydrazoic acid by using a safe and scalable high-temperature microreactor approach
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Harnessing hydrazoic acid in a microreactor! Tetrazoles have been synthesized in a very efficient manner by using a high-temperature/high-pressure process intensification regime. Despite the toxic and explosive nature of hydrazoic acid, the synthesis was conducted safely in continuous flow format with residence times as short as 2.5 minutes at 260□°C (see picture).
- Gutmann, Bernhard,Roduit, Jean-Paul,Kappe, C. Oliver,Roberge, Dominique
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supporting information; experimental part
p. 7101 - 7105
(2010/11/05)
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- Antimony trioxide as an efficient Lewis acid catalyst for the synthesis of 5-substituted 1H-tetrazoles
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Sb2O3 was found to be effective as a catalyst for a smooth (2 + 3) cycloaddition of sodium azide with nitriles to afford 5-substituted 1H-tetrazoles in good yields. Copyright Taylor & Francis Group, LLC.
- Venkateshwarlu,Rajanna,Saiprakash
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experimental part
p. 426 - 432
(2009/05/30)
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