Sodium Hydroxide → racemic (2'R,3R,4'S)-6-chloro-2',4'-bis(3-chlorophenyl)spiro[3H-indole-3,3'-piperidine]-2,6'-dione

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Reaction Steps

To a solution of racemic (2′R,3R,4′S)-6-chloro-2′,4′-bis(3-chlorophenyl)-2,3-dihydro-2,6′-dioxospiro[indole-3,3′-piperidine]-1-carboxylic acid ethyl ester prepared in example 4c (0.45 g, 0.92 mmol) in methanol (30 mL) was added NaOH (66 mg, 1.65 mmol). The mixture was stirred at room temperature for 0.5 h. The solvent was removed and the residue was partitioned between ethyl acetate and aqueous HCl solution (1 N). The aqueous layer was extracted with ethyl acetate. The organic layers were combined and then concentrated. The residue was purified with chromatography (EtOAc:CH2Cl2=1:3) to give racemic (2′R,3R,4′S)-6-chloro-2′,4′-bis(3-chlorophenyl)spiro[3H-indole-3,3′-piperidine]-2,6′-dione as a white solid (Yield 0.2 g, 51%).

Provenance & Evidence