4-propionyl-3-(4-substitutedphenylamino) isoxazol- 5(2H)-one, substituted on nitrogen with a 2-chlorobenzothiazole group, reacts with triethylamine (TEA) in ethanol under reflux conditions to provide a convenient synthesis of 1-(2-(4- substitutedphenyl amino) -imidazo [2,1-b] benzothiazole-3-yl) propan-1-one.