Benzyl carbazate → 1H-Benzimidazole-5-carboxylic acid, 1-cyclohexyl-2-(3-furanyl)-, hydrazide

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Reaction Steps

The benzimidazole carboxylic acid of example 2 (0.500 g, 1.61 mmol) was stirred in DMF (10 mL) with N-Cbz-hydrazine (0.268 g, 1.61 mmol), TBTU (0.620 g, 1.93 mmol) and DIEA (0.727 g, 563 mmol) for 3 days. EtOAc was added and the reaction mixture was washed twice with 10% aqueous citric acid, twice with saturated aqueous NaHCO3 and once with brine. The organic layer was dried over anhydrous MgSO4, filtered and concentrated to give a brown foam that was hydrogenolyzed in THF-EtOH (1:1) with 10% Pd/C (70 mg) under an atmosphere of hydrogen for 8 h. The suspension was filtered and concentrated to dryness to give 1-cyclohexyl-2-furan-3-yl-1H-benzoimidazole-5-carboxylic acid hydrazide as a brown foam.

Provenance & Evidence