Sodium triacetoxyborohydride (168 mg, 0.794 mmol, 3 equiv) was added to a suspension of 8-(2,6-dichloro-3,5-dimethoxy-phenyl)-quinoxaline-5-carboxylic acid (4-formyl-1H-imidazol-2-yl)-amide (125 mg, 0.265 mmol) (Example 179) and N,N,N′-trimethylethylenediamine (81 mg, 0.792 mmol, 3 equiv) in DCM (4 mL) at rt, under an argon atmosphere. The reaction mixture was stirred for 18 h at rt, diluted in DCM/H2O and extracted with DCM. The organic phase was washed with H2O and brine, dried (Na2SO4), filtered and concentrated. The residue was purified by silica gel column chromatography (DCM/MeOH/NH3aq, 94:5:1) followed by trituration in Et2O to afford 88 mg of the title compound as a yellow solid: ES-MS: 558 [M+H]+; tR=3.14 min (System 1); TLC: Rf=0.05 (DCM/MeOH/NH3aq, 94:5:1).
