119-84-6

20921-00-0

The general procedure for the synthesis of 6-bromochroman-2-one from hydrogenated cinnamic acid lactone is as follows: a solution of bromine (155 mL) in dichloromethane (500 mL) was slowly added dropwise to a solution of 3,4-dihydrocoumarin (450 g, 0.3 mol) in dichloromethane (2000 mL) over a period of 30 minutes. The reaction mixture was stirred overnight at 15 °C. After completion of the reaction, the reaction solution was diluted with dichloromethane (2000 mL) and washed sequentially with aqueous sodium bicarbonate (2 x 1000 mL) and water (1000 mL). The organic phase was dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was washed with petroleum ether (2 x 500 mL), the filtrates were combined and concentrated. Finally, the target compound 6-bromochroman-2-one (BM1490) was obtained as white thick crystals (471 g, 74% yield) by recrystallization from a solvent mixture of dichloromethane/petroleum ether.