The general procedure for the synthesis of 5-bromo-2-indanone from 5-bromo-1H-indene was as follows: first, 1.5 L of 30% H2O2 and 300 mL of formic acid were added to a reaction flask, and the temperature of the reaction was controlled at 35 °C. Subsequently, 148 g of 5-bromo-1H-indene was added to the reaction mixture at 40 °C. The reaction mixture was stirred at room temperature for 12 hours. Upon completion of the reaction, a large amount of water was added to the reaction mass to precipitate a white solid, which was subsequently filtered. Next, 3 L of 5% aqueous sulfuric acid solution was added to the flask and heated to boiling. The white solid reactant was added to the flask and connected to a distillation unit to obtain a final 64 g of 5-bromo-2-indanone (white solid).
