1,3-Cyclohexanedione → 8-oxo-9-[5-(4,5,6-trifluoro-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

Participants

Reaction Steps

A suspension of 190 mg (1.23 mmol) of 3-amino-2-ethoxycarbonylpyrrole and 367 mg (1.23 mmol) of 5-(4,5,6-trifluoro-1H-benzimidazol-2-ylsulfanyl)-furan-2-carbaldehyde (obtained from step 2) in 6.5 mL of n-butanol under argon is stirred at room temperature for 15 minutes. 1,3-Cyclohexanedione (138 mg, 1.23 mmol) is then added and the reaction mixture is heated at reflux temperature for 2 h. The mixture is then cooled to room temperature and concentrated under reduced pressure. The residue is taken up in 5 mL of ethanol, cooled to 0° C. and triturated. The solid is filtered, washed with 1 mL of ethanol and 3 times with 5 mL of diisopropylether and dried under reduced pressure. 144 mg of 8-oxo-9-[5-(4,5,6-trifluoro-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 are obtained as a yellow crystalline powder. mp: 186° C. LCMS-DAD-ELSD: 527(−): [M−H]−; 529(+): [M+H]+.

Provenance & Evidence