- Iron-promoted sulfur sequestration for the substituent-dependent regioselective synthesis of tetrazoles and guanidines
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We have established a facile and versatile synthetic methodology for the construction of tetrazoles and guanidines in the presence of an eco-friendly, inexpensive, easily available iron reagent. Aromatic thioureas with electron-donating substituents produced their respective target products in quantitative yield. In contrast, when electron-withdrawing substituted aromatic thioureas were used, the expected products were obtained in reduced yield. However, the desired products were obtained in good yield at moderate temperature. In addition, mechanistic studies revealed that the synthetic route involved iron-based subsequent reactions of addition and removal of sulfur.
- Pendem, Venkata Bhavanarushi,Tamminana, Ramana,Nannapaneni, Madhavi
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p. 499 - 509
(2021/04/09)
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- Selective Gold-Catalysed Synthesis of Cyanamides and 1-Substituted 1H-Tetrazol-5-Amines from Isocyanides
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The newly discovered gold-catalysed reaction of isocyanides with hydrazoic acid generated in situ from trimethylsilyl azide and methanol (or, alternatively, from NaN3/AcOH) produces either cyanamides or 1-substituted 1H-tetrazol-5-amines, depending on the amount of available HN3. The reaction proceeds selectively and in generally high yields of either product, thus providing a particularly convenient access to a wide range of substituted 1H-tetrazol-5-amines that are rather difficult to access otherwise.
- ?koch, Karel,Císa?ová, Ivana,?těpni?ka, Petr
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supporting information
p. 13788 - 13791
(2018/09/14)
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- Cobalt-promoted one-pot reaction of isothiocyanates toward the synthesis of aryl/alkylcyanamides and substituted tetrazoles
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[Figure not available: see fulltext.] The synthesis of cyanamides and tetrazoles from isothiocyanates through tandem reaction using cobalt catalyst has been demonstrated. In the case of tetrazole preparation, the reaction involved addition/desulfurization/nucleophilic addition/electrocyclization, whereas aromatic cyanamides were constructed from isothiocyanates through addition/desulfurization. Cheap cobalt sulfate was used for the synthesis of various cyanamides and tetrazoles. In addition, cobalt catalyst was found to be desulfurization reagent that has not been previously reported. The final products have been obtained from starting precursors in good to high yield.
- Seelam, Mohan,Kammela, Prasada Rao,Shaikh, Bajivali,Tamminana, Ramana,Bogiri, Sujatha
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p. 535 - 544
(2018/07/05)
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