Ammonium Chloride → 1-(diphenylmethyl)-3-hydroxy-3-(5-hydroxy-1-benzothiophen-6-yl)-1,3-dihydro-2H-indol-2-one

Participants

Reaction Conditions

Reaction Steps

To a solution of benzo[b]thiophen-5-ol (1.39 g, 9.25 mmol) in tetrahydrofuran (50 mL) at 5° C. was added a 2 M solution of isopropylmagnesium chloride in tetrahydrofuran (5.0 mL, 10 mmol). The reaction mixture was stirred at 5° C. for 15 min and concentrated in vacuo. To the residue were added 1,2-dichloroethane (100 mL) and 1-(diphenylmethyl)-1H-indole-2,3-dione (2.5 g, 8.0 mmol). The reaction mixture was heated at reflux for 3 h, allowed to cool to ambient temperature and stirred for 48 h. Saturated aqueous ammonium chloride (10 mL) was added and the phases were separated. The organic phase was dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was purified by column chromatography and eluted with a 0% to 20% gradient of ethyl acetate in dichloromethane to afford 1-(diphenylmethyl)-3-hydroxy-3-(5-hydroxy-1-benzothiophen-6-yl)-1,3-dihydro-2H-indol-2-one (2.2 g, 59%) as an off-white solid: MS (ES+) m/z 486.0 (M+23).

Provenance & Evidence