1H-Benzimidazole,5,6-difluoro-(9CI)

64-18-6

76179-40-3

78581-99-4

The general procedure for the synthesis of 5,6-difluorobenzimidazole from 4,5-difluorophthalimide and formic acid was as follows: 4,5-difluorophthalimide (1.5 g, 10 mmol) was dissolved in formic acid (20 mL) and the reaction was heated for 12 hr at 80 °C. Upon completion of the reaction, the mixture was cooled to 25 °C and subsequently concentrated under reduced pressure to remove the solvent. The resulting residue was purified by recrystallization from a solvent mixture of petroleum ether and ethyl acetate (15:1, v/v) to give the final yellow solid 5,6-difluoro-1H-benzo[d]imidazole (1.4 g, 88% yield). Mass spectrum (ESI) m/z: 155 [M + H]+.