1,3-Cyclohexanedione → 8-oxo-9-[5-(5-trifluoromethoxy-1H-benzimidazol-2-ylsulfanyl)-furan-2-yl]-4,5,6,7,8,9-hexahydro-2H-pyrrolo[3,4-b]quinoline-3-carboxylic acid ethyl ester

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Reaction Steps

A mixture of 3-amino-2-ethoxycarbonyl-pyrrole (0.235 g, 1.52 mmol), 5-(5-trifluoromethoxy-1H-benzoimidazol-2-ylsulfanyl)-furan-2-carbaldehyde (0.50 g, 1.52 mmol) and 1,3-cyclohexanedione (0.171 g, 1.52 mmol) in 5 ml of 1-butanol is heated at reflux temperature for 4 hours. The reaction mixture is then concentrated under reduced pressure. The residue is then purified on a silica gel column (40 g) eluted successively with cyclohexane/ethyl acetate (7/3, v/v) and cyclohexane/ethyl acetate (1/1, v/v). The fractions containing the expected product are concentrated under reduced pressure. The obtained solid is washed with acetonitrile (100 ml), pentane (50 ml) and dried under vacuum to yield 310 mg of 8-oxo-9-[5-(5-trifluoromethoxy-1H-benzimidazol-2-ylsulfanyl)-furan-2-yl]-4,5,6,7,8,9-hexahydro-2H-pyrrolo[3,4-b]quinoline-3-carboxylic acid ethyl ester as a white powder. Yield=36%. Analytical LC/MS (method C): m/z=559 (positive ion mode [M+H]+), m/z=557 (negative ion mode [M−H]−).

Provenance & Evidence