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Two approaches for the synthesis of levo-praziquantel.

Haowen ShouZhaoting HeGang PengWei-Ke SuJingbo Yu
Published in: Organic & biomolecular chemistry (2022)
We report herein the development of two pathways for the preparation of levo-praziquantel (R-PZQ), which involves three-/four-step processes of a mechanochemical (asymmetric) aza-Henry/acylation reaction, a hydrogenation reaction, (chiral resolution) and a solvent-free acylation-ring closing reaction. The key intermediate (R)-1-aminomethyl tetrahydroisoquinoline could be obtained either by chiral resolution with a rational reuse of the S-isomer or by mechanochemical enantioselective synthesis that refrained from using a bulky toxic solvent. The efficiency and scalability of both the developed routes were demonstrated and desired target product was obtained in a satisfactory yield with excellent enantiopurity (>99%), offering practical, concise and environmentally friendly alternatives to access R-PZQ.
Keyphrases
  • ionic liquid
  • single molecule
  • capillary electrophoresis
  • electron transfer
  • wastewater treatment
  • mass spectrometry
  • low cost