Hydrochloric Acid → 7-Iodo-1H-benzimidazol-5-amine

Participants

Reaction Steps

A solution of 10 g of SnCl2.2H2O and 20 ml of HCl was added into 2,4-dinitro-6-iodoaniline (4.1 g, 13 mmol) and resulting reaction mixture was stirred at reflux for 48 h. The reaction mixture was then basified by adding 15% aq. NaOH and extracted with CHCl3 several times. Combined extracts were dried over MgSO4 and concentrated in vacuo, yielding oily residue which was subjected to column chromatography (5% MeOH/EtOAc) to yield 1.1 g (4.4 mmol, 33%) of the amine. The amine was stirred at reflux in 10 ml of formic acid and 10 ml of acetic anhydride for 12 h. The reaction mixture was concentrated in vacuo to yield an oily residue which was stirred in 30 ml of HCl sat'd EtOH for 2 h. The oily reaction mixture after concentration was subjected to column chromatography (5% NH3 sat'd MeOH/EtOAc) to provide 0.69 g (2.7 mmol,60%) of the desired product.

Provenance & Evidence