4-bromo-1-N-tert-butylbenzene-1,2-diamine

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 4-bromo-N1-tert-butyl-benzene-1,2-diamine (500 mg, 2.06 mmol) in DMF (20 mL) is added 2-formyl-benzonitrile (270 mg, 2.06 mmol) at room temperature. Oxone (758 mg, 1.23 mmol) is added and the solution is stirred at the same temperature for 2 hours. The reaction mixture is poured into 0.5 M K2CO3 solution (30 mL). The product is extracted into EtOAc (3×) and the combined organics are then dried (Na2SO4), filtered, and concentrated. Purification via flash chromatography (25 g silica gel, 0-4% MeOH/CH2Cl2) affords 2-(5-bromo-1-tert-butyl-1H-benzimidazol-2-yl)-benzonitrile (765 mg, 100%). The product is extracted into EtOAc (3×) the combined organics are then dried (Na2SO4) filtered concentrated Purification via flash chromatography (25 g silica gel, 0-4% MeOH/CH2Cl2)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 4-bromo-N1-tert-butyl-benzene-1,2-diamine (700 mg, 2.8 mmol) in DMF (15 mL) is added 2-(3-methyl-1,2,4-oxadiazol-5-yl)benzaldehyde (813 mg, 4.3 mmol) at room temperature. Oxone (1.7 g, 2.8 mmol) in H2O (4 mL) is added and the solution is stirred for 1 hour. Saturated sodium thiosulfate solution (10 mL) is added and the mixture is extracted with EtOAc (3×10 mL) and H2O (10 mL). The combined organic layer is dried, (MgSO4), filtered and concentrated. The residue is purified by silica gel flash column chromatography eluting with 10% MeOH in CH2Cl2 to afford the 5-bromo-1-tert-butyl-2-[2-(3-methyl-1,2,4-oxadiazol-5-yl)-phenyl]-1H-benzimidazole (900 mg, 76%) as a pale brown solid. the mixture is extracted with EtOAc (3×10 mL) and H2O (10 mL) The combined organic layer is dried, (MgSO4), filtered concentrated The residue is purified by silica gel flash column chromatography eluting with 10% MeOH in CH2Cl2