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General procedure for the synthesis of 6-bromo-8-aminoquinoline from 6-bromo-8-nitroquinoline: to a mixed solution of 6-bromo-8-nitroquinoline (4 g, 1.58 mmol) in ethanol/acetic acid/water (50 mL/50 mL/25 mL) was added iron powder (3.18 g, 5.69 mmol). The reaction mixture was heated to reflux for 3 hours. Upon completion of the reaction, it was cooled to room temperature, neutralized with 2.5 N sodium hydroxide solution, filtered through diatomaceous earth to remove the iron powder residue, and the filter cake was washed with ethyl acetate. The filtrate was extracted with ethyl acetate (3 x 200 mL), the organic phases were combined, dried with anhydrous sodium sulfate and concentrated under reduced pressure. The oil obtained was purified by column chromatography (40% ethyl acetate/hexane) to give 3.19 g (91% yield) of yellow solid with a melting point of 142-145 °C. The residue was extracted with ethyl acetate (3 x 200 mL) and dried with anhydrous sodium sulfate.

[1] Patent: EP1147083, 2004, B1. Location in patent: Page 46
[2] Monatshefte fuer Chemie, 1994, vol. 125, # 6/7, p. 723 - 730
[3] Journal fuer Praktische Chemie (Leipzig), 1894, vol. <2> 49, p. 534,539