Ethanol → 5-methoxy-1H-benzimidazole

Beteiligte Stoffe

Reaktionsschritte

4-Methoxy-1,2-phenylenediamine (5.00 g, 36 mmol) was dissolved in formic acid (10 ml) and heated at reflux for 2 hours. The solution was allowed to cool to room temperature overnight then treated with calcium carbonate (5.0 g). After dilution with ethanol (150 ml) the mixture was heated at reflux for 1 h then filtered, the residue being washed with hot ethanol (50 ml). The combined filtrates were evaporated at reduced pressure to give an oil from which a solid crystallised. The material was slurried with diethyl ether (50 ml) then filtered to give an orange solid which was recrystallised from ethyl acetate to give 5-methoxybenzimidazole (5.33 g, 99%) as a yellow crystalline solid.

Herkunft & Nachweise