Stannous Chloride → 3-Chloro-4,5-difluoro-1,2-diaminobenzene

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3-Chloro-4,5-difluoro-1,2-diaminobenzene 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-3,4-difluoro-6-nitroaniline (160 mg, 0.767 mmol) and SnCl2 2H2O (0.863 g, 3.84 mmol) was dissolved in 5 mL ethyl acetate and 2 mL absolute ethanol under N2 and heated at 75° C. for 5 h. The reaction was allowed to cool to room temperature and poured into 50 mL H2O. Sufficient sat'd NaHCO3 solution was added (foaming!) to bring the pH to 7. The resulting mixture was extracted with 3×20 mL ethyl acetate and the combined organic extracts washed with 20 mL sat'd NaCl solution. The organic phase was dried (MgSO4), vacuum filtered and the solvent rotary evaporated to yield a brown solid, 124 mg (91%). 1H NMR (CDCl3) δ3.52 (br s, 4H, 2(NH2)); 6.49 (dd, 1H, JHF =7.5, 10.8 Hz, H-6). There was 13% 4,5-difluoro-1,2-diaminobenzene present by NMR.

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