Synthesis 2003(7): 1079-1082
DOI: 10.1055/s-2003-39179
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Novel Chemoselective Annulation of Imidazole and 1,2,4-Thiadiazine Rings on Azoles Involving Acid Labile Methanesulfinyl Group

Lal Dhar S. Yadav*, Ritu Kapoor
Department of Chemistry, University of Allahabad, Allahabad 211 002, India
Fax: +9(532)2545021; e-Mail: lds-yadav@hclinfinet.com;
Further Information

Publication History

Received 3 February 2003
Publication Date:
09 May 2003 (online)

Abstract

Oxa(thia)diazole adducts 2a-d, DMSO and azole Schiff bases 1a-d are chemoselectively annulated with sulfuric acid, acetic acid, and thionyl chloride to yield imidazo[2,1-b]-1,3,4-oxa(thia)diazoles 3a-d. Their 5-methylsulfenyl analogues 4a-d and 1,3,4-oxa(thia)diazolo[3,2-b]-1,2,4-thiadiazines 5a-d, respectively, 3-5 are formed via demethylsulfinylation, the Pummerer rearrangement, and deoxygenative demethylation, in a one-pot procedure.