2-(Heterocyclylthio)benzonitriles and process for preparing 3-(1-piperazinyl)-1,2-benzisothiazole

2-(Heterocyklylthio)benzonitrily obecn ho vzorce IIa, kde R.sup.1.n.' p°edstavuje skupinu vzorce a nebo b. Zp sob v²roby 3-(1-piperazinyl)-1,2-benzizothiazolu vzorce I, p°i n m se slou enina obecn ho vzorce II, kde R.sup.1.n. p°edstavuje skupinu vzorce a, b nebo c nech reagovat s piperazinem p°i teplot od 80 do 170 .degree.C. 3-(1-Piperazinyl)-1,2-benzizothiazol je kl ov² meziprodukt p°i v²rob ziprasidonu.\ In the present invention there are disclosed 2-(heterocyclylthio)benzonitriles of the general formula IIa, in which Re1' represents the group of the general formula a or b. Disclosed is also process for preparing 3-(1-piperazinyl)-1,2-benzisothiazole of the general formula I, which process is characterized by reacting the compound of the general formula II, in which Re1 represents the group of the general formula a, b or c with piperazine at a temperature ranging from 80 to 170 degC. The 3-(1-piperazinyl)-1,2-benzisothiazole is a key intermediate for preparing ziprasidone.