The reaction of benzoisothiazole-3(2H)-one-1,1-dioxide (I) with 1,4-dibromobutane (II) by means of NaH in DMF gives 2-(4-bromobutyl)benzoisothiazole-3(2H)-one-1,1-dioxide (III), which is then condensed with 1-(2 pyrimidinyl)piperazine (IV) by means of K2CO3 in refluxing chlorobenzene.