A 1 liter round bottom flask equipped with stirring rod, thermo pocket, reflux condenser and nitrogen inlet was charged with 10 gm (0.04 moles) of 11-chlorodibenzo[b,f][1,4]-thiazepine (I), 100 cc toluene and the mixture was stirred for 15 min. at room temperature. The resulting solution was combined with 7.7 gm (0.044 mole) of 1-(2-hydroxyethoxy)ethylpiperazine (II), 8.5 gm (0.08 mole) of sodium carbonate carbonate and 7.7 gm (0.24 mole) of tetra butyl ammonium bromide. The reaction mixture was heated at gentle reflux for 22 hrs and a sample of the reaction mixture was analyzed by HPLC. The analysis revealed that less than 2% of the starting material remained. The reaction mixture was cooled to room temperature and combined with 300 cc 1N hydrochloric acid solution to get a pH in between 1 to 2. The layers were separated and the aqueous layer was diluted with 100 cc toluene and pH was adjusted between 8 to 9 by addition of sodium carbonate. The layers (aqueous and nonaqueous reaction solvent toluene) were separated and the aqueous layer was extracted with 100 cc toluene. The organic (toluene) layers were combined and washed with 2×100 cc of water. The reaction solvent (toluene) was distilled-off under vacuum at 70 to 80° C. to afford 12 gm oil. HPLC area %: 98.87
