N-Iodosuccinimide-Promoted [3 + 2] Annulation Reaction of Aryldiazonium Salts with Guanidines To Construct Aminotetrazoles
Yi-Lin Yang, Shen Li, Fa-Guang Zhang* and Jun-An Ma*
*Department of Chemistry, Tianjin University, Tianjin 300072, P. R. of China, Email: zhangfg1987tju.edu.cn, majun_an68tju.edu.cn
Y.-L. Yang, S. Li, F.-G. Zhang, J.-A. Ma, Org. Lett., 2021, 23, 8894-8898.
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N-Iodosuccinimide promotes a [3 + 2] annulation reaction of aryldiazonium salts with guanidines for the construction of previously elusive 2-aryl-5-amino-2H-tetrazoles. This transformation takes advantage of readily available starting materials, proceeds under metal-free, mild, and robust conditions, and offers broad functional group compatibility.
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General procedure for the synthesis of aminotetrazoles from aryldiazonium salts and guanidines
A 25 mL tube equipped with a magnetic stir bar was charged with aryl diazonium salt (0.2 mmol), guanidine hydrochloride (0.4 mmol, 2 equiv), and NIS (45 mg, 0.2 mmol, 1 equiv), then MeOH (3 mL) was added as the solvent. After the aryl diazonium salt was dissolved, DBU (0.15 mL, 1 mmol, 5 equiv) was added slowly as the base. The mixture reacted 1 hour at room temperature. After the reaction was completed (monitored by TLC), removal of the solvent is operated under reduced pressure. The residue was further purified by a silica gel column chromatography (petroleum ether / EtOAc = 5:1, v/v) to obtain the corresponding product.