Hydrochloric Acid → 7-bromo-2-methyl-3H-benzo[d]imidazol-5-amine

Temperature

65 °C

To a solution of 4-bromo-2-methyl-6-nitro-1H-benzo[d]imidazole (35 g, 137 mmol) and Tin(II) chloride dihydrate (185 g, 822 mmol) in methanol (800 mL) was added conc. HCl (10 mL), and the mixture was stirred at 65° C. for 2 h. Then the solvent was removed in vacuo, and the residue was diluted with 1N Na2CO3 solution (600 mL) and extracted with ethyl acetate (500 mL×3). The combined organic layers were washed with brine, dried over sodium sulphate and evaporated to give the crude product (30.2 g, 97%) as a brown solid; LC/MS: MS (ES+) m/e 226 [M+H]+; 1H NMR (300 MHz, DMSO-d6) δ ppm 2.38 (s, 3H), 4.98 (s, 2H), 6.52 (d, J=1.5 Hz, 1H), 6.66 (d, J=1.5 Hz, 1H), 11.86 (s, br, 1H).

1. customThen the solvent was removed in vacuo
2. additionthe residue was diluted with 1N Na2CO3 solution (600 mL)
3. extractionextracted with ethyl acetate (500 mL×3)
4. washThe combined organic layers were washed with brine
5. dry with materialdried over sodium sulphate
6. customevaporated

ORD record

ord-c5f8509a470347b780a3ba6e991d1202

Source dataset

uspto-grants-2014_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08778937B2