Asymmetric total syntheses of both enantiomers of plymuthipyranone b and its unnatural analogues: Evaluation of anti-mrsa activity and its chiral discrimination

Mizuki Moriyama, Xiaoxi Liu, Yuki Enoki, Kazuaki Matsumoto, Yoo Tanabe

Research output: Contribution to journalArticlepeer-review

Abstract

Chiral total syntheses of both enantiomers of the anti-MRSA active plymuthipyranone B and all of the both enantiomers of three unnatural and synthetic analogues were performed. These two pairs of four chiral compounds are composed of the same 3-acyl-5,6-dihydro-2H-pyran-2-one structure. The starting synthetic step utilized a privileged asymmetric Mukaiyama aldol addition using Ti(OiPr)4/(S)-BINOL or Ti(OiPr)4/(R)-BINOL catalysis to afford the corresponding (R)-and (S)-δ-hydroxy-β-ketoesters, respectively, with highly enantiomeric excess (> 98%). Conventional lactone formation and successive EDCI-mediated C-acylation produced the desired products, (R)-and (S)-plymuthipyranones B and three (R)-and (S)-synthetic analogues, with an overall yield of 42–56% with a highly enantiomeric excess (95–99%). A bioassay of the anti-MRSA activity against ATCC 43300 and 33591 revealed that (i) the MICs of the synthetic analogues against ATCC 43300 and ATCC 33591 were between 2 and 16 and 4 and 16 μg/mL, respectively, and those of vancomycin (reference) were 1 μg/mL. (ii) The natural (S)-plymuthipyranone B exhibited significantly higher activity than the unnatural (R)-antipode against both AACCs. (iii) The natural (R)-plymuthipyra-none B and (R)-undecyl synthetic analogue at the C6 position exhibited the highest activity. The present work is the first investigation of the SAR between chiral R and S forms of this chemical class.

Original languageEnglish
Article number938
JournalPharmaceuticals
Volume14
Issue number9
DOIs
Publication statusPublished - 2021 Sep

Keywords

  • Anti-MRSA activity
  • Asymmetric total syntheses
  • Chiral discrimination
  • Enantiomers
  • Plymuthipyranone B

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmaceutical Science
  • Drug Discovery

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