Synthesis
(1) A bromine solution was prepared by dissolving 7.8 g of bromine in 30 mL of dichloromethane. In another reaction flask, 13 g of 5-acetyl-8-benzyloxy-1H-quinolin-2-one and 7.56 g of boron trifluoride ether compound were dissolved in 170 ml of dichloromethane and heated to reflux. Subsequently, the bromine solution was slowly added dropwise to the refluxed solution and the reflux reaction was continued for 30 minutes. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was adjusted to alkaline by adding 10% aqueous potassium carbonate solution and the resulting precipitate was collected by filtration. The resulting crude product was purified by recrystallization from a solvent mixture of chloroform and methanol, resulting in 12.51 g of 5-bromoacetyl-8-benzyloxy-1H-quinolin-2-one as light yellow acicular crystals in 75.7% yield.
References
[1] Patent: US4579854, 1986, A
[2] Patent: WO2012/168349, 2012, A1. Location in patent: Page/Page column 30-31
[3] Patent: WO2012/168359, 2012, A1. Location in patent: Page/Page column 56; 57
[4] Patent: US2013/34504, 2013, A1. Location in patent: Paragraph 0120; 0121; 0122
[5] Patent: US2014/163066, 2014, A1. Location in patent: Paragraph 0209-0211
