Formic Acid → 4-Methylbenzimidazole

A solution of 3-methylbenzene-1,2-diamine (500 mg, 4.1 mmol) in formic acid (4.5 mL, 120 mmol) was irradiated in a microwave oven for 15 min at 135° C. The reaction mixture was cooled to ambient temperature and the formic acid was removed under reduced pressure. The residue was dissolved in ethyl acetate (20 mL) and extracted with saturated aqueous NaHCO3 (2×10 mL), water (10 mL) and brine (10 mL). The organic phase was dried over anhydrous Na2SO4 and the solvent was removed in vacuum yielding 4-methyl-1H-benzoimidazole (519 mg, 96%). Calculated for C8H8N2 m/z: 132.07, found 133.13 [M+H]+. 1H NMR (400 MHz, DMSO-d6) δ ppm 2.50 (s, 3H), 6.96 (m, 1H), 7.06 (m, 1H), 7.38 (d, J=7.6 Hz, 1H), 8.15 (s, 1H), 12.41 (s, 1H).

1. customthe formic acid was removed under reduced pressure
2. dissolutionThe residue was dissolved in ethyl acetate (20 mL)
3. extractionextracted with saturated aqueous NaHCO3 (2×10 mL), water (10 mL) and brine (10 mL)
4. dry with materialThe organic phase was dried over anhydrous Na2SO4
5. customthe solvent was removed in vacuum

ORD record

ord-5007e90cd4344c0c8fe46eccfafba4f8

Source dataset

uspto-grants-2010_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07645784B2