Trifluoroacetic acid → 6-Chloro-4'-(3-chlorophenyl)-2'-(5-fluoro-2-methylphenyl)-2,3-dihydro-1'-methyl-2,6'-dioxo spiro[indole-3,3'-piperidine]-1-ethanol

Participants

Reaction Steps

To a solution of racemic (2′R,3R,4′S)-6-chloro-4′-(3-chlorophenyl)-2′-(5-fluoro-2-methylphenyl)-2,3-dihydro-1′-methyl-2,6′-dioxospiro[indole-3,3′-piperidine]-1-methoxyethyl trimethylsilane (0.16 g, 0.26 mmol) prepared in example 56a in dichloromethane (10 mL) was added trifluoroacetic acid (20 mL). The reaction mixture was stirred at room temperature for 3 h. The reaction mixture was concentrated. The residue was neutralized with saturated NaHCO3 aqueous solution, then extracted with ethyl acetate. The organic layer was separated, dried over MgSO4 and concentrated. The residue was purified by chromatography (EtOAc:CH2Cl2=1:1) to give racemic (2′R,3R,4′S)-6-chloro-4′-(3-chlorophenyl)-2′-(5-fluoro-2-methylphenyl)-2,3-dihydro-1′-methyl-2,6′-dioxospiro[indole-3,3′-piperidine]-1-ethanol (Yield 90 mg, 67.7%).

Provenance & Evidence