General procedure for the synthesis of 8-benzyloxy-5-((R)-2-bromo-1-hydroxyethyl)-1H-quinolin-2-one from 1-(8-(benzyloxy)-2-hydroxyquinolin-5-yl)-2-bromoacetophenone: Under nitrogen protection, the tetrahydrofuran (1400 mL) and 1-(8-(benzyloxy)-2-hydroxyquinolin-5-yl)-2-bromoacetophenone (100 g) were The mixture was cooled to 0-5°C. Subsequently, R-methyl CBS (7.5 g) was slowly added and boron dimethyl sulfide complex (24.3 g) was added at 0-10°C. The reaction was carried out at 0-10°C. The reaction was carried out at 0-10°C. The reaction mixture was stirred at 0-10°C for 1-2 h. The reaction progress was monitored by HPLC. Upon completion of the reaction, methanol (100 mL) was slowly added and stirring was continued at 0-10°C for 15 min. Subsequently, the reaction mixture was distilled under vacuum at 40-45°C and then cooled to 25-30°C. The cooled reaction mixture was slowly added to hydrochloric acid solution and stirred for 1-2 h at 25-30°C. The reaction mixture was then purified by HPLC. The resulting solid was filtered, washed with water (300 mL) and dried at 65-70°C for 8 hours. The product yield was 95%.
[1] Patent: US2016/326118, 2016, A1. Location in patent: Paragraph 0067; 0068
[2] Patent: US2004/224982, 2004, A1. Location in patent: Page 3; 10
[3] Patent: US2004/242622, 2004, A1. Location in patent: Page 30
[4] Patent: US2004/167167, 2004, A1. Location in patent: Page/Page column 34
[5] Patent: US2006/35933, 2006, A1. Location in patent: Page/Page column 25