反应 #82571

反应方程式

NaHCO3

2-bromo-3,4-difluoro-6-nitroaniline

SnCl2.2H2O

ethanol

→

3-Bromo-4,5-difluoro-1,2-diaminobenzene

溶剂

—

hexanes

ethyl acetate

ethyl acetate

反应条件

后处理

1. 1
   其他All the starting material had reacted
2. 2
   workup.ADDITIONpoured into 20 mL
3. 3
   其他crushed ice
4. 4
   workup.ADDITIONwas added (foaming!)
5. 5
   萃取The thick yellow white emulsion was then extracted with 3×25 mL ethyl acetate
6. 6
   洗涤the combined organic extracts washed with sat'd NaCl solution
7. 7
   干燥The organic phase was dried (MgSO4), vacuum
8. 8
   过滤filtered
9. 9
   其他the solvent rotary evaporated
10. 10
    其他to yield a dark brown oil which
11. 11
    其他crystallized
12. 12
    其他to yield 410 mg (66%)

实验过程

3-Bromo-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-bromo-3,4-difluoro-6-nitroaniline (700 mg, 2.78 mmol) and SnCl2.2H2O (3.14 g, 13.9 mmol) dissolved in 7 mL ethyl acetate and 3 mL absolute ethanol under N2 was heated at 75° C. for 2 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 sat'd NaHCO3 solution was added (foaming!) to bring the pH to 5. 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 410 mg (66%). 1H NMR (CDCl3) δ3.59 (br s, 4H, 2(NH2)); 6.52 (m, 1H, H-6).

来源