399-97-3

White to brown solid

The general procedure for the synthesis of 2-amino-4-fluorophenol from 2-nitro-4-fluorophenol was as follows: tin(II) chloride (12.1 g, 63.6 mmol) was added to a solution of 4-fluoro-2-nitrophenol (2.00 g, 12.7 mmol) in ethanol (45 mL). The reaction mixture was heated to 70 °C and maintained at this temperature for 2 hours. Upon completion of the reaction, the mixture was cooled to room temperature and subsequently poured into ice water (~200 mL). After the mixture was warmed to room temperature, the pH was adjusted with 2N NaOH aqueous solution to about 9. The reaction mixture was filtered and the filtrate was extracted with ethyl acetate (3×). The organic phases were combined, dried with anhydrous sodium sulfate, filtered and the organic phase was concentrated under reduced pressure. 1.21 g (75% yield) of 2-amino-4-fluorophenol was finally obtained.Results of LC-MS analysis: retention time (RT) = 4.48 min, [M + H]+ = 128.0.

[1] Patent: EP1346982, 2003, A1
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[3] Patent: WO2007/146066, 2007, A2. Location in patent: Page/Page column 80
[4] Journal of Organic Chemistry, 1951, vol. 16, p. 1345,1348
[5] J. Gen. Chem. USSR (Engl. Transl.), 1975, vol. 45, p. 2372 - 2379