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Synthesis of 5-amino-3-(het)aryl-1H-1,2,4-triazoles via Cyclization of(het)aroylaminoguanidines in Aqueous Medium
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1  Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore

Abstract: The effective and clean procedure for the preparation of 5-amino-3-(het)aryl-1,2,4-triazoles (3a-c) via cyclization of (het)aroylaminoguanidines (2a-c) in water was reported. Two tautomeric forms, namely 5-amino-3-(het)aryl-1,2,4-triazoles (A) and 3-amino-5-(het)aryl-1,2,4-triazoles (B) were found to exist in tautomeric equilibrium. Form A was a predominant tautomer in DMSO solution (KT = 9-33).
Keywords: 1,2,4-triazoles; acylaminoguanidines; cyclization; aqueous medium; tautomerism