A stirred solution of 8.0 g 3-fluoro-8-isopropyldibenzo(b,f)thiepin-10(11H)-one in 55 ml benzene is treated with a solution of 2.8 g titanium tetrachloride in 14 ml benzene added dropwise. 14 g of 1-methylpiperazine are then slowly added and the mixture refluxed for 16 hours. After cooling, it is decomposed with 80 ml water, added dropwise. 100 ml benzene are then added and the separated solid is filtered. The benzene layer of the filtrate is washed with water, dried with potassium carbonate and evaporated. There are obtained 9.2 g (89%) crude oily base which is neutralized with maleic acid in ethanol. Addition of ether separates the crystalline maleate of 3-fluoro-8-isopropyl-10-(4-methylpiperazino)dibenzo(b,f)thiepin melting at 183°-184° C. with decomposition (ethanol-ether).
