O-Phenylenediamine → 2-(6-hydroxyheptyl)-1H-benzimidazole

3.28 g of methyl 6-hydroxyheptanoate and 2.16 g of phenylenediamine were dissolved in a mixed solvent of 10 ml of concentrated hydrochloric acid and 20 ml of water, and the mixture was refluxed with stirring under heating for 24 hours. After cooling to room temperature, the reaction mixture was adjusted to pH 8 with about 100 ml of 1 N sodium hydroxide solution and saturated aqueous sodium hydrogencarbonate. The reaction mixture was extracted three times with 150 ml of ethyl acetate, and the organic layer was washed with saturated brine and dried over sodium sulfate. After the solvent was evaporated under reduced pressure, the residue was purified by silica gel column chromatography (ethyl acetate—ethyl acetate:methanol=95:5) to obtain 3.03 g of the title compound as pale brown solid (yield: 70%).

1. temperaturethe mixture was refluxed
2. temperatureunder heating for 24 hours
3. extractionThe reaction mixture was extracted three times with 150 ml of ethyl acetate
4. washthe organic layer was washed with saturated brine
5. dry with materialdried over sodium sulfate
6. customAfter the solvent was evaporated under reduced pressure
7. customthe residue was purified by silica gel column chromatography (ethyl acetate—ethyl acetate:methanol=95:5)

ORD record

ord-ee688e649acc4f45a02be7b9f5f62125

Source dataset

uspto-grants-2004_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06815455B1