In a 100 mL round bottom flask, 12 (0.32 g, 0.76 mmol) was dissolved in C6H6 (50 mL). An ethereal solution of 1.0 M HCl in Et2O (0.76 mL, 0.76 mmol) was added to the stirring solution, and the mixture was allowed to react at RT for 1 h. The volatile components were removed under reduced pressure and the resulting product was recrystallized in heptane to yield the product as a white powder. Yield: 0.23 g, 80%.