Heating of 2,5-dichloroacetophenone with 2-thiophenethiol, potassium carbonate and copper gave 5-chloro-2-(2-thienylthio)acetophenone (V) which was subjected to the Willgerodt reaction with sulphur and morpholine. The product was a mixture of the thiomorpholide VI and oxothiomorpholide VII. After a partial separation the predominanting product VI was hydrolyzed without characterization with ethanolic potassium hydroxide to give the acid VIII. Cyclization by treatment with phosphorus pentoxide in boiling toluene gave 7-chlorothieno[2,3-b]-1-benzothiepin-4(5H)-one (X) which was reduced with sodium borohydride to the alcohol XII. A reaction with hydrogen chloride in benzene led to the chloro derivative XIII whose substitution reaction with 1-(2-hydroxyethyl)piperazine afforded the title compound IV. The product has strong central depressant and discoordinating activity, a low cataleptic efficity but in a relatively high dose it does not influence the dopamine metabolism in the rat brain.