5-Nitrobenzimidazole → HCID 178437240, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-nitro-benzimidazole (2.8 g, 17 mmol) in THF was added 16 ml of EtMgBr solution (48 mmol) and reaction mixture was stirred for 2 h at −15° C. A solution of tetrachloro-1,4-benzoquinone (8.8 g, 36 mmol) in THF was added dropwise into reaction mixture, which was allowed to warm up to 25° C. over 1 h. Silica gel(20 g) was added into reaction mixture and solvent was removed in vacuo to provide a brown silica gel powder which was subjected to column chromatography (EtOAc, neat) to provide 1.7 g (8.9 mmol, 52%) of 4-ethyl-5-nitrobenzimidazole, which was subsequently subjected to hydrogenation (H2, Pd/C) to yield 1.32 g (8.2 mmol) of 4-ethyl-5-aminobenzimidazole.

Provenance & Evidence