Reaktion #9055

Reaktionsgleichung

2,3-diaminotoluene

trimethylorthoformate

trifluoroacetic acid

→

4-methyl-1H-benzimidazole

Lösungsmittel

CH2Cl2

CH2Cl2

Reaktionsbedingungen

Aufarbeitung

1. 1
   Waschenwashed consecutively with saturated aqueous NaHCO3 (40 mL) and H2O (40 mL)
2. 2
   TrocknenThe combined organic extracts were dried over MgSO4
3. 3
   Einengenconcentrated to a rusty brown solid (1.07 g, 97%)

Vorschrift

To a stirred solution of 2,3-diaminotoluene (1.00 g, 8.2 mmol) in CH2Cl2 (82 mL) was added trimethylorthoformate (4.5 mL, 41 mmol) and trifluoroacetic acid (0.32 mL, 4.1 mmol) and the mixture stirred at room temperature for 24 h after which the reaction mixture was diluted with CH2Cl2 (200 mL), and washed consecutively with saturated aqueous NaHCO3 (40 mL) and H2O (40 mL). The aqueous layers were reextracted with CH2Cl2 (2×100 mL). The combined organic extracts were dried over MgSO4 and concentrated to a rusty brown solid (1.07 g, 97%). 1H NMR (300 MHz, CDCl3) δ 8.08 (s, 1H), 7.49 (d, 1H, J=8.1 Hz), 7.23–7.18 (m, 1H), 7.10 (d, 1H, J=7.5 Hz), 2.64 (s, 3H).

Quelle