Ethyl 3-furoate → 3-(3-Furoyl)-2-oxindole

Reaction equation

[Na].[NH:2]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH2:4][C:3]1=[O:11].[O:12]1[CH:16]=[CH:15][C:14]([C:17](OCC)=[O:18])=[CH:13]1>C(O)C>[O:12]1[CH:16]=[CH:15][C:14]([C:17]([CH:4]2[C:5]3[C:10](=[CH:9][CH:8]=[CH:7][CH:6]=3)[NH:2][C:3]2=[O:11])=[O:18])=[CH:13]1

Participants

Procedure

To a stirred solution of 2.8 g (0.12 mole) of sodium in 200 ml of ethanol was added 13.3 g (0.10 mole) of 2-oxindole, followed by 16.8 g of ethyl 3furoate. The mixture was heated under reflux for 47 hours, cooled and then the solvent was removed by evaporation in vacuo. The residue was triturated under 200 ml of ether, and the solid was collected by filtration and discarded. The filtrate was evaporated in vacuo, and the residue triturated under diisopropyl ether and recovered by filtration. The solid was suspended in 250 ml of water, which was then acidified with concentrated hydrochloric acid. This mixture was stirred to give a solid, which was recovered by filtration. This latter solid was recrystallized from acetic acid followed by acetonitrile to give 705 mg of the title compound, mp 185°-186° C.