Synthesis
To a 500 mL three-necked flask was added 4-nitrophenol (15 g, 108 mmol), 3-chloropropionic acid (11.6 g, 108 mmol), an aqueous ethanol solution (150 mL) and a 20% aqueous potassium hydroxide solution (150 mL). The reaction mixture was heated to reflux for 6 hours. After completion of the reaction, the mixture was cooled to room temperature and the pH was adjusted to 1-3 with dilute hydrochloric acid. the reaction mixture was extracted with ethyl acetate (300 mL x 3), the organic phases were combined and washed with saturated aqueous sodium chloride solution (300 mL x 2). The organic phase was dried over anhydrous sodium sulfate, filtered and concentrated. The crude product was purified by silica gel column chromatography (eluent: ethyl acetate/petroleum ether=1:4, v/v) to afford 3-(4-nitrophenoxy)propionic acid (8.8 g, yield 38.6%) as a white solid.
References
[1] Patent: CN108440404, 2018, A. Location in patent: Paragraph 0075; 0076; 0077; 0078
[2] Patent: WO2005/37830, 2005, A1. Location in patent: Page/Page column 18
[3] Patent: WO2012/119559, 2012, A1. Location in patent: Page/Page column 96-97
[4] Patent: WO2014/418, 2014, A1. Location in patent: Page/Page column 96; 97
[5] Patent: US2015/197511, 2015, A1. Location in patent: Paragraph 0448; 0449
