p-Toluenesulfonic acid → HCID 66874385, compound

Participants

Reaction Steps

The crude (S)-methyl 2-((S)-1-(methylamino)propan-2-ylamino)propanoate was dissolved in ethanol (30 mL) and p-toluenesulfonic acid (175 mg) was added. The reaction mixture was heated to reflux for 18 h and then concentrated under reduced pressure. The residue was partitioned between CH2Cl2 (40 mL) and saturated NaHCO3 (20 mL). The aqueous layer was separated and extracted again with CH2Cl2 (20 mL). The combined organic layers were dried (Na2SO4) and concentrated under reduced pressure to give (3S,5S)-1,3,5-trimethylpiperazin-2-one (230 mg, 43% which contains 2,6-lutidine, ca 2:1 product:2,6-lutidine) as an amber oil. 1H NMR consistent.

Provenance & Evidence