Synthesis 2012; 44(21): 3378-3386
DOI: 10.1055/s-0032-1317504
paper
© Georg Thieme Verlag Stuttgart · New York

A Diversified Assembly of 1,2,4-Oxadiazol-3-amines: Metallic Thiophile Catalyzed Chemoselective One-Pot Reaction of Aryl Isothiocyanates, Amidines/Guanidines, and Hydroxylamine

Hitesh B. Jalani
Department of Medicinal Chemistry, B.V. Patel Pharmaceutical Education and Research Development (PERD) Centre, Sarkhej-Gandhinagar Highway, Thaltej, Ahmedabad 380 054, Gujarat, India   Fax: +91(79)27450449   eMail: kamkva@gmail.com
,
V. Sudarsanam
Department of Medicinal Chemistry, B.V. Patel Pharmaceutical Education and Research Development (PERD) Centre, Sarkhej-Gandhinagar Highway, Thaltej, Ahmedabad 380 054, Gujarat, India   Fax: +91(79)27450449   eMail: kamkva@gmail.com
,
Kamala K. Vasu*
Department of Medicinal Chemistry, B.V. Patel Pharmaceutical Education and Research Development (PERD) Centre, Sarkhej-Gandhinagar Highway, Thaltej, Ahmedabad 380 054, Gujarat, India   Fax: +91(79)27450449   eMail: kamkva@gmail.com
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Publikationsverlauf

Received: 05. Juni 2012

Accepted after revision: 07. September 2012

Publikationsdatum:
09. Oktober 2012 (online)


In loving memory of my grandfather, S. J. Jalani

Abstract

An efficient one-pot synthesis of 1,2,4-oxadiazol-3-amines from simple starting materials, isothiocyanates, amidines/guanidines, and hydroxylamine, is described. The reaction is facilitated by metallic-thiophile-assisted desulfurization of in situ formed amidino- or guanidinothiourea to give chemoselectively N-hydroxyguanidine intermediates that give exclusively various 1,2,4-oxadiazol-3-amines in good to excellent yields. The reaction mechanistic pathway may proceed through an intramolecular 5-exo-trig cyclization.