To a solution of 6-piperazin-1-yl-2-(2-trifluoromethylphenylamino)-1H-benzimidazole-5-carboxylic acid (1H-indazol-6-yl)-amide trihydrochloride (0.25 mmol; see Example 88) in methanol (1 mL) was added glyoxylic acid (0.5 mmol), and the resulting mixture was stirred at RT for 60 min. The reaction mixture was then charged with solid sodium cyanoborohydride (0.6 mmol), and the stirring was continued at RT for 10 h. To the reaction mixture was then added a few drops of glacial acetic acid, and the mixture was stirred for 30 min. The volatiles were then removed in vacuo, and the residue was suspended in water (10 mL) with vigorous stirring. After 30 min, the solid was filtered, washed with water, and dried under vacuum to afford {4-[6-(1H-indazol-6-ylcarbamoyl)-2-(2-trifluoromethyl-phenylamino)-3H-benzoimidazol-5-yl]-piperazin-1-yl}acetic acid as a white solid. MS: m/z 579 (M+H)+.
