Cyanogen Bromide → HCID 178507355, compound

Temperature

60 °C

Alternate synthesis of a substituted 2-aminobenzimidazole. A mixture of 5-fluoro-2-nitro-phenylamine (1 mmol), an amine (2 mmol) in THF (20 mL) is heated at about 60° C. overnight. After cooling the mixture to room temperature, the reaction mixture is concentrated. The crude material is purified on a silica gel column to yield a 5-amino-2-nitro-phenylamine. The 5-amino-2-nitro-phenylamine (1.0 mmol) is dissolved in an ethyl acetate-methanol mixture (about 1:1, 10 mL) in a round-bottom flask. To this solution Pd—C is added, and the mixture is stirred under a hydrogen atmosphere, while monitoring the reaction with thin-layer chromatography (TLC). After TLC shows completion of the reaction, the solution is filtered on celite and then washed with methanol and concentrated to obtain a 4-amino-benzene-1,2-diamine. The 4-amino-benzene-1,2-diamine (1 mmol) is dissolved in ethanol and CNBr (1.5 mmol) is added. The resulting dark brown solution is heated at 60° C. for 30 minutes. Thereafter, the mixture is cooled to room temperature, and the solvent is evaporated. Then, the mixture is co-evaporated with toluene about two times to obtain a 5-amino-1H-benzoimidazol-2-ylamine as a hydrobromide salt. The reaction scheme below provides an illustration that accompanies this textual description.

1. temperatureThereafter, the mixture is cooled to room temperature
2. customthe solvent is evaporated

ORD record

ord-8b5ac3c6b96649c396ade4f760938aa5

Source dataset

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08350039B2