Trifluoroacetic acid → racemic (2'R,3R,4'S)-6-chloro-4'-(3-chlorophenyl)-1'-methyl-2'-(2-methylphenyl)spiro[3H-indole-3,3'-piperidine]-2,6'(1H)-dione

Participants

Reaction Steps

Trifluoroacetic acid (5 mL) was added to a solution of racemic (2′R,3R,4′S)-6-chloro-4′-(3-chlorophenyl)-2,3-dihydro-1′-methyl-2′-(2-methylphenyl)-2,6′-dioxospiro[indole-3,3′-piperidine]-1-carboxylic acid tert-butyl ester (0.20 g, 0.35 mmol) prepared in example 24c in dichloromethane (10 mL). The mixture was stirred at room temperature for 1 h. The solvent was evaporated in vacuo. To this residue was added saturated NaHCO3 solution, and extracted with ethyl acetate. The organic layers were combined, washed with water and brine, dried over MgSO4. The solvent was removed and the residue was purified by chromatography (EtOAc:CH2Cl2=1:4) to give racemic (2′R,3R,4′S)-6-chloro-4′-(3-chlorophenyl)-1′-methyl-2′-(2-methylphenyl)spiro[3H-indole-3,3′-piperidine]-2,6′(1H)-dione as a white solid (Yield: 0.075 g, 46%).

Provenance & Evidence