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

関与物質

反応手順

1,2-Diamino-3-chloro-5-fluorobenzene was prepared using an adaptation of the method of Bellamy, et al., (Bellamy, F. D. et al., Tetrahedron Lett. 25:839 (1984)). A mixture of 2-chloro-4-fluoro-6-nitroaniline (424 mg, 2.22 mmol) and SnCl2 2H2O (2.50 g, 11.1 mmol) dissolved in 7 mL ethyl acetate and 3 mL absolute ethanol under N2 was heated at 70° C. for 2.5 h. 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 (foaming ) to bring the pH to 6. The thick yellow white emulsion was then extracted with 3×25 mL ethyl acetate and the combined organic extracts washed with sat'd NaCl solution. The organic phase was dried (MgSO4), vacuum filtered and the solvent rotary evaporated to yield a dark brown oil which crystallized on standing to yield 290 mg (82%). 1H NMR (CDCl3) δ3.59 (br s, 4H, 2(NH2)); 6.37 (dd, 1H, H5, J4-5 =2.7, JH-F =9.3); 6.55 (dd, 1H, H4, J4-5 =2.7, JHF =8.4).

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