In a manner similar to the method described in example 60b, (2′R,3R,4′S)-6-chloro-4′-(3-chloro-phenyl)-1′-(3-chloro-propyl)-2′-isopropenyl-2,3-dihydro-2,6′-dioxospiro[indole-3,3′-piperidine]-1-methoxyethyl trimethylsilane prepared in example 123a (0.2 g, 0.20 mmol) was reacted with 1-piperazin-1-yl-ethanone (0.51 g, 4 mmol), trifluoroacetic acid (2 mL) and then N,N′-diisopropylethylamine (2 mL) to give racemic (2′R,3R,4′S)-1′-[3-(4-acetyl-piperazin-1-yl)-propyl]-6-chloro-4′-(3-chlorophenyl)-2′-isopropenylspiro[3H-indole-3,3′ piperidine]-2,6′(1H)-dione as a yellow solid (Yield: 95 mg, 50.8%).
