(S)-1,5-dimethylpiperazin-2-one

To a stirred solution of (S)-1,5-dimethyl-4-((trimethyl-oxidaneyl)carbonyl)piperazin-2-one (1.50 g, 6.5 mmol) in 1,4-dioxane (15 mL), HC1(ol,3-dimethyl-4-[2-t4-tpiperidin-4-vnphenoxy) ethyl piperazine-2-one) in 1,4-dioxane (15 mL) was charged dropwise at 0 °C and stirred for 16 h at room temperature. TLC indicated the reaction. After the completion, the reaction mixture was concentrated to afford (S)-1,5-dimethylpiperazin-2-one as a gummy solid.