Synthesis
The general procedure for the synthesis of 6-fluoro-2-aminophenol from 2-fluoro-6-nitrophenol was as follows: 2-fluoro-6-nitrophenol (6.37 mmol, 1.00 g) was dissolved in methanol (100 mL), and 10% activated charcoal-loaded palladium catalyst (10% by weight of 2-fluoro-6-nitrophenol, 0.10 g) was added. The reaction system was displaced first with argon and then with hydrogen, each displacement lasting 15 min, during which magnetic stirring was maintained. Subsequently, the reaction was carried out at atmospheric pressure (using a hydrogen balloon) and under hydrogen atmosphere for 1 hour. Upon completion of the reaction, the gas in the reaction vessel was again replaced with argon for 15 minutes. The reaction mixture was filtered through a diatomaceous earth pad and washed with methanol (50 mL). The filtrate was concentrated under vacuum to give a red solid product. Purification by silica gel column chromatography (eluent ratio 1:1 hexane/chloroform) gave a white crystalline solid in 87% yield.
References
[1] Bioorganic and Medicinal Chemistry Letters, 2014, vol. 24, # 15, p. 3521 - 3525
[2] Patent: JP2016/124812, 2016, A. Location in patent: Paragraph 0115
[3] Patent: US2010/298334, 2010, A1. Location in patent: Page/Page column 46
[4] Patent: WO2005/118561, 2005, A1. Location in patent: Page/Page column 25
[5] Patent: US2005/124667, 2005, A1. Location in patent: Page/Page column 17
