Trifluoroacetic acid → racemic (2'S,3S,4'R)-6-chloro-2'-(3-chlorophenyl)-4'-(5-fluoro-2-methyl-phenyl)-1'-hydroxycarbonylmethyl-spiro[3H-indole-3,3'-piperidine]-2,6'(1H)-dione

Participants

Reaction Steps

To a solution of racemic (2′S,3S,4′R)-6-chloro-2′-(3-chlorophenyl)-4′-(5-fluoro-2-methyl-phenyl)-2,3-dihydro-1′-[(tert-butoxycarbonyl)methyl]-2,6′-dioxospiro[indole-3,3′-piperidine]-1-methoxyethyl trimethylsilane (0.85 g, 1.19 mmol) prepared in example 146d in dichloromethane (10 mL) was added trifluoroacetic acid (20 mL). The reaction mixture was stirred at room temperature for 18 h. The reaction mixture was concentrated. The residue was redissolved in methanol (10 mL). To the resulting solution was added N,N′-diisopropylethylamine (1.57 mL, 8.70 mmol) and the crude was refluxed for 1 h. The reaction mixture was concentrated and the residue was partitioned between ethyl acetate and HCl aqueous solution (1N). The organic layer was separated, dried over MgSO4 and concentrated. The residue was triturated with ethyl acetate and hexane to give racemic (2′S,3S,4′R)-6-chloro-2′-(3-chlorophenyl)-4′-(5-fluoro-2-methyl-phenyl)-1′-hydroxycarbonylmethyl-spiro[3H-indole-3,3′-piperidine]-2,6′(1H)-dione as a yellow solid (Yield 440 mg, 70%).

Provenance & Evidence