反応 #82571

反応方程式

NaHCO3

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

SnCl2.2H2O

ethanol

→

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

溶媒

—

hexanes

ethyl acetate

ethyl acetate

反応条件

後処理

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

実験手順

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).

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