In a three-neck round bottom flask, dissolve 2.86 g (10 mmol) of Intermediate-1 in 40 mL of CCl4. Dropped in a round bottom flask 4.00 g (25 mol) of Br 2 and 30 mL of CCl 4 were added to the funnel, and the mixture was slowly dropped into a round bottom flask over 4 hours N2 is injected to remove HBr generated. When dropping is completed, stirring is carried out under N2 air flow for 1 hour When the reaction was terminated, the resulting precipitate was filtered as it was, and the precipitate was recrystallized using toluene to give (2.8 g, 58%).
