An aqueous medium synthesis and tautomerism study of 3(5)-amino-1,2,4-triazoles
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A catalyst-free highly efficient synthesis of 3(5)-amino-5(3)-(het)aryl-1,2,4-triazoles in aqueous mediumwas performed using conventional heating and microwave irradiation. The tautomerism in the productswas 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 1H-forms, the 4H-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 theestablished relationship were also identified.
NOTICE: This is the author's version of a work that was accepted for publication in Tetrahedron Letters. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Tetrahedron Letters, 50, 18, 2009. DOI: 10.1016/j.tetlet.2009.02.172
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