Реакция #9062

Уравнение реакции

(2-nitrophenyl)-terephthalamic acid methyl ester

acetic acid

→

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

Выход 86.0%

Условия реакции

Обработка

1. 1
   Температураat reflux for 1 h
2. 2
   ТемператураThe mixture was cooled
3. 3
   workup.STIRRINGstirred at room temperature for 2 h
4. 4
   Концентрированиеconcentrated under reduced pressure
5. 5
   ДругоеThe residue was partitioned between saturated sodium bicarbonate (10 mL) and ethyl acetate (10 mL)
6. 6
   Другоеthe phases separated
7. 7
   Промывкаthe organic layer washed with saturated NaHCO3 (10 mL)
8. 8
   ЭкстракцияThe organic extract
9. 9
   Сушкаwas dried (MgSO4)
10. 10
    Фильтрацияfiltered
11. 11
    Концентрированиеconcentrated

Методика

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)).

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