反応 #9062

反応方程式

(2-nitrophenyl)-terephthalamic acid methyl ester

acetic acid

→

methyl 4-(benzimidazol-2-yl)-benzoate

収率 86.0%

反応条件

後処理

1. 1
   温度at reflux for 1 h
2. 2
   温度The mixture was cooled
3. 3
   workup.STIRRINGstirred at room temperature for 2 h
4. 4
   濃縮concentrated under reduced pressure
5. 5
   その他The residue was partitioned between saturated sodium bicarbonate (10 mL) and ethyl acetate (10 mL)
6. 6
   その他the phases separated
7. 7
   洗浄the organic layer washed with saturated NaHCO3 (10 mL)
8. 8
   抽出The organic extract
9. 9
   乾燥was dried (MgSO4)
10. 10
    ろ過filtered
11. 11
    濃縮concentrated

実験手順

To a solution of (2-nitrophenyl)-terephthalamic acid methyl ester (0.23 g, 0.76 mmol) in glacial acetic acid (2.5 mL) was added iron powder (<5 μm mesh, 0.12 g, 2.1 mmol) and the mixture stirred at reflux for 1 h. The mixture was cooled, stirred at room temperature for 2 h and concentrated under reduced pressure. The residue was partitioned between saturated sodium bicarbonate (10 mL) and ethyl acetate (10 mL), the phases separated and the organic layer washed with saturated NaHCO3 (10 mL). The organic extract was dried (MgSO4), filtered and concentrated to give cyclized methyl 4-(benzimidazol-2-yl)-benzoate (0.163 g, 86%). 1H NMR (CDCl3) δ 3.96 (s, 3H), 7.32 (m, 2H), 7.53 (br, 1H), 7.84 (br, 1H), 8.17 (m, 4H), 9.65 (br, 1H (NH)).

出典