1,1'-Carbonyldiimidazole → 2-(3-[1,3]dioxolan-2-ylmethylphenyl)-1H-benzimidazole-4-carboxamide

Beteiligte Stoffe

Reaktionsschritte

A solution of 3-(1,3-dioxolan-2-ylmethyl)benzoic acid (1.0 g, 4.80 mmol) in a mixture of pyridine (5 mL) and N,N-dimethylformamide (5 mL) was treated with 1,1′-carbonyldiimidazole (0.856 g, 5.28 mmol) at 45° C. for 2 hours. 2,3-diaminobenzamide dihydrochloride (synthesized as described in U.S. Pat. No. 6,737,421, column 11, EXAMPLE 2, step (e), 1.08 g, 4.80 mmol) was added and the mixture stirred at ambient temperature overnight. The mixture was concentrated and the residue purified by flash chromatography on silica gel with 10% methanol in 2:1 ethyl acetate/hexane. The product was dissolved in acetic acid (20 mL) and the solution heated at 60° C. for 2 hours and at 80° C. for 1.5 hours, cooled and concentrated and the residue partitioned between ethyl acetate and sodium bicarbonate solution. The organic phase was concentrated and the residue purified on silica gel with 10% methanol in 2:1 ethyl acetate/hexane to give 1.13 g of the title compound. MS (APCI) m/z 324 (M+H)+.

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