934192-22-0

(1) 5.04 g of 2,3-dihydro-1H-quinolin-4-one was dissolved in 20 mL of tetrahydrofuran at 25 °C. Subsequently, 5.6 mL of benzyl chloroformate, 15 mL of water and 4.73 g of potassium carbonate were sequentially added to this solution. The reaction mixture was stirred continuously at 25°C for 24 hours under cooling in an ice bath. Upon completion of the reaction, ethyl acetate was added to the mixture for extraction, and the organic layer was separated and dried with anhydrous magnesium sulfate. The dried organic phase was filtered and the filtrate was concentrated and the residue was dissolved in 35 mL of isopropanol by heating. The solution was slowly cooled and filtered under ice bath cooling to collect the precipitated crystals. The resulting crystals were washed with 25 mL of cold isopropanol and dried at 50 °C for 16 h. 8.98 g (yield: 93%) of benzyl 4-oxo-3,4-dihydroquinoline-1(2H)-carboxylate was finally obtained. Mass spectrum (APCI) m/z: 282 [M + H]+; infrared spectrum (ATR) ν: 1708, 1683 cm-1.

[1] Patent: WO2007/40240, 2007, A1. Location in patent: Page/Page column 20-21
[2] Patent: EP1941881, 2008, A1. Location in patent: Page/Page column 14
[3] Patent: WO2009/61596, 2009, A1. Location in patent: Page/Page column 319