Hydrochloric Acid → 4-bromo-1-(3-chloro-2-methylbenzyl)-2-(trifluoromethyl)-1H-benzo[d]imidazol-6-amine

To a 100 mL round-bottom flask containing MeOH (25 mL) was added 4-bromo-1-(3-chloro-2-methylbenzyl)-6-nitro-2-(trifluoromethyl)-1H-benzo[d]imidazole (5.3 g, 11.81 mmol), tin(II) chloride dihydrate (8.00 g, 35.4 mmol) and hydrochloric acid (4.92 mL, 59.1 mmol). The resultant suspension was heated to 50° C. and monitored by LC/MS. By LC/MS the reaction was complete in 30 minutes. After the reaction had cooled to room temperature, the majority of the MeOH was removed in-vacuo and 6N aqueous sodium hydroxide solution was added to adjust the pH to pH>10 and the mixture was extracted with ethyl acetate (50 mL). The organic layer was washed with H2O and brine then dried over MgSO4 and filtered. The solvent was removed in vacuo and the crude solid was purified by chromatography on silica gel eluted with chloroform/(solution of 2N ammonia in methanol) [95:5]. The fractions corresponding to product were combined, then concentrated in vacuo to provide 4-bromo-1-(3-chloro-2-methylbenzyl)-2-(trifluoromethyl)-1H-benzo[d]imidazol-6-amine (3.78 g, 9.03 mmol, 76% yield) as a light yellow solid. MS (ES+) m/e: 419.0, 420.0 [M+H]+; 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 7.34 (d, J=8.08 Hz, 1H) 6.95-7.05 (m, 2H) 6.21-6.32 (m, 2H) 5.39 (s, 2H) 3.84 (s, 2H) 2.49 (s, 3H)