One-pot regioselective synthesis of new 5-(arylsulfonylamino)imidazo(2,1-b)thiazoles

N-(2,2-Dichloro-2-phenylethylidene)-4-chlorobenzenesulfonamide reacts with 2-aminothiazoles to give products of nucleophilic addition in good yields. The adducts are cyclized into the unexpected 5-(arylsulfonyl)amino-6-phenylimidazo(2,1-b)thiazoles in 70-75% yield; whereas the anticipated isomeric 6-(arylsulfonyl)amino-5-phenylimidazo(2,1-b)thiazoles were not observed.