Title of article :
Tandem synthesis of [1,2,4]-triazoles mediated by iodine—a regioselective approach
Author/Authors :
Srimanta Guin، نويسنده , , Saroj Kumar Rout، نويسنده , , Nilufa Khatun، نويسنده , , Tuhin Ghosh، نويسنده , , Bhisma K. Patel، نويسنده ,
Issue Information :
هفته نامه با شماره پیاپی سال 2012
Pages :
9
From page :
5066
To page :
5074
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.
Keywords :
Tandem reaction , Triazole , Regioselective , Iodine
Journal title :
Tetrahedron
Serial Year :
2012
Journal title :
Tetrahedron
Record number :
1104607
Link To Document :
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