Bromine → 7-bromo-3,4-dihydro-2H-1-benzopyran-4-one

Participants

Reaction Steps

Into a round bottom flask kept at 0° C., AlCl3 (0.533 g, 3.99 mmol) and, 5 mL of CH2Cl2 was added. The reaction system was put under nitrogen and stirred for about 7 minutes before adding 10 mL of a CH2Cl2 solution of 4-chromanone (0.296 g, 1.99 mmol). After the reaction mixture was stirred for 10 minutes, 10 mL of Br2 (0.352 g, 2.20 mmol) was added and, the reaction mixture was stirred at room temperature for an hour. At the end of this period of time, the reaction mixture was poured into 30 mL of ice-water and, the product was extracted 3 times from the aqueous phase with EtOAc. The resultant organic phase was washed once with brine and dried under Na2SO4. After the solvent was evaporated, the solid formed was filtered and dried to obtain 0.361 g (1.51 mmol) of the product (93% pure) in a 74% yield.

Provenance & Evidence