An aqueous medium synthesis and tautomerism study of 3(5)-amino-1,2,4-triazoles

A catalyst-free highly efficient synthesis of 3(5)-amino-5(3)-(het)aryl-1,2,4-triazoles in aqueous medium was performed using conventional heating and microwave irradiation. The tautomerism in the products was investigated using NMR spectroscopy and X-ray crystallography. The effects of the substitu...

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Bibliographic Details
Published in:Tetrahedron letters 2009-05, Vol.50 (18), p.2124-2128
Main Authors: Dolzhenko, Anton V., Pastorin, Giorgia, Dolzhenko, Anna V., Chui, Wai Keung
Format: Article
Language:English
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Summary:A catalyst-free highly efficient synthesis of 3(5)-amino-5(3)-(het)aryl-1,2,4-triazoles in aqueous medium was performed using conventional heating and microwave irradiation. The tautomerism in the products was investigated using NMR spectroscopy and X-ray crystallography. The effects of the substitution, temperature, solvents, and concentration on the tautomerism were studied. The triazoles were found to exist in 1 H-forms, the 4 H-form was not observed either in solid state or in solution. In general, 5-amino-1,2,4-triazoles were electronically preferred in the tautomeric equilibrium, but some exceptions from the established relationship were also identified.
ISSN:0040-4039
1873-3581
DOI:10.1016/j.tetlet.2009.02.172