Methyl iodide → 1-methyl-1H-1,3-benzodiazol-5-amine

Participants

Reaction Steps

A solution of 5-nitrobenzimidazole (3.0 g, 18.4 mmol) in 100 ml of THF was stirred with NaH (2.7 g, 36.8 mmol) for 0.5 h at 25° C. To the solution was added methyl iodide (2.0 ml, 20.3 mmol) and resulting mixture was stirred for 12 h. The reaction mixture was concentrated in vacuo to provide an oil, which was dissolved in 200 ml of MeOH and stirred with 0.3 g of 10% Pd/C under H2 for 12 h. The reaction mixture was filtered and concentrated in vacuo, yielding a dark oily residue which was subjected to column chromatography (3% MeOH/CHCl,) to provide 0.69 g (3.9 mmol, 21%) of 1-methyl-5-aminobenzimidazole and 0.36 g (2.0 mmol, 11%) of 3-methyl-5-aminobenzimidazole.

Provenance & Evidence