ChemInform Abstract: Synthesis of a Novel Triheterocyclic Framework via 1,3-Dipolar Cycloaddition of a Nitrile Oxide with Imidazo[2,1-b][1,3]thiazole-3(2H)-ones

A novel series of (9Z)-9-arylmethylidene-3-(2,6-dichlorophenyl)-5,6-dihydro[1,3]thiazolo[2′,3′:2,3]imidazo [1,2-d][1,2,4]oxadiazol-8(9H)-one derivatives were prepared in moderate yields by the 1,3-dipolar cycloaddition reaction of a nitrile oxide with (2Z)-2-arylmethylidene-5,6-dihydroimidazo [2,1-b][1,3]thiazol-3(2H)-ones. The reaction site of the dipolarphile is the C═N of imidazo[2,1-b][1,3]thiazole rather than the expected C═C of the arylmethylidene. The product structures were characterized thoroughly by IR, MS, NMR spectroscopy, and elemental analysis. The results indicate that this reaction proceeds with chemoselectivity and regioselectivity.