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

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Reaction Steps

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.

Provenance & Evidence