Tandem synthesis of [1,2,4]-triazoles mediated by iodine—a regioselective approach

Guin, Srimanta ; Rout, Saroj Kumar ; Khatun, Nilufa ; Ghosh, Tuhin ; Patel, Bhisma K. (2012) Tandem synthesis of [1,2,4]-triazoles mediated by iodine—a regioselective approach Tetrahedron, 68 (25). pp. 5066-5074. ISSN 0040-4020

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Official URL: https://www.sciencedirect.com/science/article/pii/...

Related URL: http://dx.doi.org/10.1016/j.tet.2012.04.042

Abstract

A tandem regioselective one-pot synthesis of 3-amino-[1,2,4]-triazoles has been achieved from 1,3-disubstituted thioureas using molecular iodine. In this one-pot strategy, the intermediate carbodiimide generated in situ from thiourea upon reaction with HCONHNH2 gives diaryl/alkylhydrazinecarboximidamide or acylureidrazone, which then undergoes an intramolecular cyclodehydration to afford the corresponding 3-amino-[1,2,4]-triazole. The product regioselectivity for unsymmetrical 1,3-disubstituted thioureas correlate well with the pKas of the parent amines attached, in which the amine having higher pKa goes to the ring nitrogen while the other nitrogen remains flanked as an exocyclic nitrogen of the triazole core. This method is milder and environmentally sustainable giving good to excellent yields of the desired products.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Tandem Reaction;Triazole; Iodine; Regioselective
ID Code:113907
Deposited On:02 May 2018 04:49
Last Modified:02 May 2018 04:49

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