反应详情

温度

110 °C

5-(3-furanyl)-1-(3-(ethoxycarbonyl)phenyl)benzimidazole(6c1) To a solution of 1d (2.07 g, 10 mmol) in NMP (2 ml) was added ethyl 3-aminobenzoate (1.82 g, 11 mmol) and triethylamine and the mixture was heated to 110° C. in a nitrogen atmosphere overnight. The mixture was diluted with ice-water and extracted with ethyl acetate. The concentrated extract was purified by column-chromatography on silica gel using a mixture of petroleum ether and ethyl acetate (9:1 v/v) to yield ethyl 3-(N-(4-(3-furanyl)-2-nitrophenyl))aminobenzoate (1.18 g, 34%). This ester was hydrogenated in ethanol at ambient pressure using Pd (5% on activated carbon) as the catalyst. The resulting diamine (1.07 g) was treated with triethyl orthoformate (1.11 ml, 6.64 mmol) and a catalytic amount of pTSA in refluxing THF (10 ml). Column-chromatographic work-up of the concentrated reaction mixture using ethyl acetate as the eluent afforded 6c1 (0.66 g, 56%). M.p. 87-89° C.

1. extractionextracted with ethyl acetate
2. extractionThe concentrated extract
3. customwas purified by column-chromatography on silica gel using
4. additiona mixture of petroleum ether and ethyl acetate (9:1 v/v)