Hydrochloric Acid → 4-(1h-Imidazol-2-ylcarbamoyl)-1h-benzoimidazole-2-carboxylic acid

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Reaction Steps

To a stirring solution of 200 mg (0.92 mmol) of 2,3-diamino-N-(1H-imidazol-2-yl)-benzamide (synthesized as described in Intermediate-B) in 2.0 mL of acetic acid was added 200 mg (1.15 mmol) of 2,2,2-trichloroacetamide and stirring continued for 30 min at r.t. Then 0.5 mL of 1% HCl in methanol was added and stirred for another 45 min at r.t. Evaporation of the solvent gave the crude ester, which was dissolved in 4:1 THF and methanol (5 mL) and then 1.0 mL of 2N LiOH was added at r.t. The reaction mixture was stirred at r.t. for 30 min, the pH was adjusted to 3.0 and then extracted with ethyl acetate twice (2×25 mL). The combined organic solvents were dried, evaporated to provide 100 mg (40%) of 4-(1H-imidazol-2-ylcarbamoyl)-1H-benzoimidazole-2-carboxylic acid, which was used, for the next step without further purification. LCMS: 272 (M+1)+.

Provenance & Evidence