Chlorosuccinimide → 1-(Thiophen-3-yl)-1,3-dihydro-2H-indol-2-one

Participants

Reaction Conditions

Reaction Steps

A solution of the above 1-(thien-3-yl)-1H-indole (6.10 g, 30.6 mmol), N-chlorosuccinimide (4.30 g, 32.2 mmol) and dichloromethane (230 mL) is stirred for 2 hr at room temperature. The solvent is then removed, the residue is dissolved in acetic acid (127 mL) and heated to 70° C. Then 85% phosphoric acid is added and the reaction mixture is heated at gentle reflux for 24 hr. After cooling to room temperature, the reaction is concentrated to about its volume, poured onto ice and water and extracted with ethyl acetate. The combined extract is washed with water, with brine, dried, filtered and concentrated. The black residue is purified by chromatography eluting with dichloromethane-0 to 5% methanol. Product containing fractions are combined and concentrated to afford 1-(thien-3-yl)-1H-indol-2-one (4.12 g, 63% yield) as a brown solid.

Provenance & Evidence