- Elucidating the Importance of Hydrochloric Acid as a Cocatalyst for Resorcinarene-Capsule-Catalyzed Reactions
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This survey of resorcinarene-capsule-catalyzed reactions demonstrates that HCl functions as a crucial cocatalyst by increasing the capsule's inherent Br?nsted acidity to enable or accelerate cationic reactions. The presence of HCl appears to be without consequences for other reactions.
- K?ster, Jesper M.,Tiefenbacher, Konrad
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- Cyanide-Free Synthesis of Air Stable N-Substituted Li and K Cyanamide Salts from Tetrazoles. Applications toward the Synthesis of Primary and Secondary Cyanamides as Precursors to Amidines
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A practical two-step synthesis of N,N′-disubstituted cyanamides consists in the low-temperature metalation of N-substituted 5H-tetrazoles that undergo spontaneous cycloreversion at 0 °C releasing dinitrogen, and forming N-metalated cyanamides that can be reacted in situ with a variety of electrophiles. Remarkably, the N-substituted Li and K cyanamides are air stable white solids at room temperature. Addition of lithium organometallics to the N,N′-disubstituted cyanamides provides a new method for accessing N,N′-disubstituted amidines.
- Duchamp, Edouard,Hanessian, Stephen
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supporting information
p. 8487 - 8491
(2020/11/12)
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- One-pot synthesis of 1- and 5-substituted 1H-tetrazoles using 1,4-dihydroxyanthraquinone–copper(II) supported on superparamagnetic Fe3O4@SiO2 magnetic porous nanospheres as a recyclable catalyst
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An effective one-pot, convenient process for the synthesis of 1- and 5-substituted 1H-tetrazoles from nitriles and amines is described using1,4-dihydroxyanthraquinone–copper(II) supported on Fe3O4@SiO2 magnetic porous nanospheres as a novel recyclable catalyst. The application of this catalyst allows the synthesis of a variety of tetrazoles in good to excellent yields. The preparation of the magnetic nanocatalyst with core–shell structure is presented by using nano-Fe3O4 as the core, tetraethoxysilane as the silica source and poly(vinyl alcohol) as the surfactant, and then Fe3O4@SiO2 was coated with 1,4-dihydroxyanthraquinone–copper(II) nanoparticles. The new catalyst was characterized using Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, dynamic light scattering, thermogravimetric analysis, vibration sample magnetometry, X-ray photoelectron spectroscopy, nitrogen adsorption–desorption isotherm analysis and inductively coupled plasma analysis. This new procedure offers several advantages such as short reaction times, excellent yields, operational simplicity, practicability and applicability to various substrates and absence of any tedious workup or purification. In addition, the excellent catalytic performance, thermal stability and separation of the catalyst make it a good heterogeneous system and a useful alternative to other heterogeneous catalysts. Also, the catalyst could be magnetically separated and reused six times without significant loss of catalytic activity. Copyright
- Esmaeilpour, Mohsen,Javidi, Jaber,Zahmatkesh, Saeed
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p. 897 - 904
(2016/10/18)
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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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p. 4362 - 4371
(2013/05/08)
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- Indium triflate-catalyzed one-pot synthesis of 1-substituted-1H-1,2,3,4-tetrazoles under solvent-free conditions
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A simple, efficient, and general method has been developed for the synthesis of 1-substituted-1H-1,2,3,4-tetrazoles via a three-component condensation of amine, trimethyl orthoformate, and sodium azide in presence of a catalytic amount of indium triflate
- Kundu, Dhiman,Majee, Adinath,Hajra, Alakananda
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experimental part
p. 2668 - 2670
(2009/08/09)
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- Synthesis of 1-substituted tetrazoles via the acid-catalyzed [3+2] cycloaddition between isocyanides and trimethylsilyl azide
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1-Substituted tetrazoles were synthesized via the [3+2] cycloaddition between isocyanides and trimethylsilyl azide in the presence of an acid catalyst and MeOH. Various 1-substituted tetrazoles were obtained in good to high yields. The reaction probably p
- Jin, Tienan,Kamijo, Shin,Yamamoto, Yoshinori
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p. 9435 - 9437
(2007/10/03)
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