Ethanol → 3,5-Dibromo-1,2-benzenediamine

Participants

Reaction Steps

3,5-Dibromo-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 2,4-dibromo-6-nitroaniline (500 mg, 1.69 mmol) and SnCl2 ·2H2O (1.90 g, 8.45 mmol) dissolved in 5 mL ethyl acetate and 2 mL absolute ethanol under N2 was heated at 70° C. for 1 h. All the starting material had reacted as evidenced by TLC (silica gel, 3:1 hexanes:ethyl acetate). The reaction was allowed to cool to room temperature and poured into 20 mL crushed ice. Sufficient sat'd NaHCO3 solution was added (foaming ) to bring the pH to 5. The thick yellow white emulsion was vacuum filtered and the filtrate 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 pale yellow oil which crystallized on standing to yield 400 mg (89%). 1H NMR (CDCl3) δ3.62 (br s, 4H, 2(NH2)); 6.78 (d, J=1.8, 1H, H-6); 7.01 (d, J=1.8, 1H, H-4).

Provenance & Evidence