Hydrochloric Acid → 3-(5-Amino-2-benzofuran-1(3H)-ylidene)-1,3-dihydro-2H-indol-2-one

Participants

Reaction Steps

To a solution containing oxindole (0.5 g, 3.76 mmol) in 7.5 mL DMF was added 7.51 mL of sodium hexamethyldisilazane (1.0 M in THF) over 3 min. After stirring 10 min at room temperature, a solution of 5-aminophthalide (0.672 g, 4.51 mmol) in 4.0 mL DMF was added over 3 min. The reaction was stirred for 30 min at room temperature and then poured into 4% aqueous HCl solution to give a yellow cloudy solution. After stirring the mixture 3 min, the solution was made basic by adding saturated NaHCO3. The yellow solid was filtered, washed with H2O, and then dissolved in CHCl3/MeOH. The solvent was removed in vacuo and the solid purified by chromatography (silica gel, CHCl3/MeOH, 95:5) to give the title compound (345 mg, 35%) as a yellow solid.

Provenance & Evidence