1-BOC-(2S,6R)-2,6-dimethylpiperazine is a commonly used drug design fragment. It can be obtained by selectively protecting (2S,6R)-2,6-dimethylpiperazine with CbzCl, then protecting the remaining secondary amine with Boc anhydride, and finally removing the Cbz protection to obtain the title compound.
A solution of 4-benzyl-1-tert-butyl(2R,6S)-2,6-dimethylpiperazine-1,4-dicarboxylate (6.350g, 18.224mmol) in ethanol (150mL) was slowly added dropwise to a stirring solution of 10% Pd/C (1g) at room temperature. The reaction mixture was stirred under a hydrogen atmosphere (H2 balloon) at the same temperature for 17 hours. The mixture was filtered through a diatomaceous earth pad to remove solids and concentrated under reduced pressure. tert-butyl (2R,6S)-2,6-dimethylpiperazine-1-carboxylate was obtained without further purification (3.820g, 97.8%, yellow oily substance).
