Synthesis
General procedure for the synthesis of 2-(4-nitrophenyl)-2-oxoacetic acid from p-nitroacetophenone: Selenium dioxide (SeO2, 0.167 g, 1.5 mmol) and p-nitroacetophenone (0.165 g, 1 mmol) were added to a 25 mL round-bottomed flask under nitrogen protection. 10 mL of anhydrous pyridine was added and the reaction mixture was heated to 110 °C in an oil bath and refluxed with stirring. After 1 h of reaction, the reaction progress was monitored by thin layer chromatography (TLC). After completion of the reaction, the mixture was cooled to room temperature and allowed to stand for 4 hours. The precipitate containing SeO2 was removed by filtration through a Brinell funnel and the residue was washed with 50 mL of ethyl acetate. The filtrates were combined and treated with 1 mmol/L hydrochloric acid (20 mL). The aqueous layer was extracted three times with ethyl acetate (50 mL) to obtain aqueous layer 2 and organic layer 2, respectively. organic layer 2 was combined and extracted three times with 25 mL of water to obtain organic layer 3 and aqueous layer 3. aqueous layer 3 was treated with 1 mmol/L NaOH (50 mL) to obtain the reaction solution. The filtrate 4 was diluted and combined into the aqueous layer 2, and the pH was adjusted to 1.5 with 1 mmol/L hydrochloric acid.The mixture was extracted with ethyl acetate (3 × 50 mL). The organic layer was dried overnight in a vacuum desiccator to give the product 4-nitrophenylglyoxalic acid in a yield of 0.154 g in 79.2% yield.
References
[1] Synthetic Communications, 2008, vol. 38, # 24, p. 4434 - 4444
[2] Patent: CN108623611, 2018, A. Location in patent: Paragraph 0041; 0043; 0044; 0045; 0046
[3] Journal of Organic Chemistry, 2018, vol. 83, # 3, p. 1422 - 1430
[4] Journal of the American Chemical Society, 2010, vol. 132, # 34, p. 11898 - 11899
[5] Chemical Communications, 2013, vol. 49, # 35, p. 3640 - 3642
