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 CN of imidazo[2,1-b][1,3]thiazole rather than the expected CC 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.