1. -Chlorophenyl)thio)methyl)-1-methylpiperidine-2,6-dione (17b);Eluent: chloroform/Methanol gradient from 99:1 to 95:5. White powder; mp 91?93 �C
2. The organic phase was washed with water (3�20 mL), brine (2�20 mL), dried over Na 2 SO 4 and then concentrated under reduced pressure. The residue was purified by column chromatography. Eluent: n-hexane/EtOAc gradient from 95:5 to 50:50. Yield: 114 mg (40 %);Brown solid; mp 97?101 �C. 1 H NMR (400 MHz