a 500 mL 2-neck round-bottomed flask was equipped with a reflux condenser and replaced by nitrogen. 70 mL of THF that was dried with 0.11 mol of Mg metal was added to the above flask and then, 0.10 mol of 1-bromo-4-(trifluoromethyl)benzene was added in a dropwise fashion. The reaction was significantly exodermic and thus a cooling bath was equipped to reduce the temperature inside the reactor less than 50° C. It was agitated for 2 hours at room temperature, 0.11 mol of zinc chloride was added with 100 mL of THF, and further agitated for 2 hours to obtain a slurry-phase reaction mixture. Another flask was replaced by nitrogen and then 4-chlorobenzothiazole derivative (0.10 mol), Pd (0.10 mol), and Pd(PPh3)4 (3 mol %) were dissolved in 100 mL of THF. The prepared solution was added to the reaction mixture and then agitated at 60° C. for 24 hours. After the reaction is complete, the resulting product was placed on a silica gel column to remove an inorganic slurry, and then a THF solution was concentrated under vacuum to obtain 4-(4-(trifluoromethyl)phenyl)benzo[d]thiazole at a yield of 91% using column chromatography.
