Ethanol → 3-Bromo-5-fluorobenzene-1,2-diamine

関与物質

反応手順

1,2-Diamino-3-bromo-5-fluorobenzene was prepared using an adaptation of the method of Bellamy et al., Tetrahedron Lett. 25:839 (1984). A mixture of 6-bromo-4-fluoro-2-nitroaniline (673 mg, 2.87 mmol) and SnCl2 2H2O (3.23 g, 14.3 mmol) dissolved in 6 mL ethyl acetate and 3 mL absolute ethanol was heated at 70° C. for 30 min. All the starting material had reacted as evidenced by TLC (silica gel, 2:1 hexanes:ethyl acetate). The reaction was allowed to cool to room temperature and poured into 20 mL crushed ice. Sufficient solid NaHCO3 was added to bring the pH to 7.5. The reaction mixture was then extracted with 3×20 mL ethyl acetate and the combined organic phases washed with sat'd NaCl solution. The organic phase was dried (MgSO4), vacuum filtered and the solvent rotary evaporated to yield a dark brown liquid 510 mg (86.7%). 1H NMR (CDCl3) δ3.64 (br s, 4H, 2(NH2)), 6.44 (dd, 1H, H5, J4-5 =2.7, JH-F =9.8), 6.72 (dd, 1H, H4, J4-5 =2.7, JH-F =8.4).

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