4.8 g of iodine-activated magnesium are covered with a layer of 60 cc of anhydrous tetrahydrofuran and cauterized with a few drops of ethylene bromide. A solution of 25.0 g of 4-chloro-1-methylpiperidine in 160 cc of anhydrous tetrahydrofuran is then added dropwise at such a rate that the solvent boils continually, and stirring is subsequently effected at the boil for 2 hours. The reaction mixture is cooled to 10°, and a solution of 20.0 g of 9,10-dihydro-10-methyl-4H-benzo[4,5]cyclohepta-[1,2-b]thiophen-4-one in 100 cc of anhydrous tetrahydrofuran is added dropwise at this temperature. After stirring at room temperature for 11/2 hours and at the boil for 30 minutes, the reaction mixture is cooled, poured on 300 cc of a 20% ammonium chloride solution, and the organic phase is separated. The aqueous solution is extracted with methylene chloride, the combined organic solutions are washed with water, dried over sodium sulphate and concentrated by evaporation. The 9,10-dihydro-10-methyl-4-(1-methyl-4-piperidyl)-4H-benzo[4,5]cyclohepta-[1,2-b]thiophen-4-ol, obtained as residue, is recrystallized twice from isopropanol. M.P. 177°-178°.
