Linker and Head-Group Exploration of Anti-MRSA Triaromatic Pleuromutilins

J Med Chem. 2025 May 8;68(9):9479-9500. doi: 10.1021/acs.jmedchem.5c00152. Epub 2025 Apr 17.

Abstract

Based on hit 6, a triaromatic pleuromutilin (TAP) and potent bacterial protein synthesis inhibitor, we explored the chemical space surrounding its pharmacophore by synthesizing 45 new conjugates. Herein, the adenine head was exchanged for new heterocycles, and the benzyl linker exchanged for aniline-, ether-, amide-, and hydroxybenzyl linkages, with all of them successfully engaging the pharmacophore, a result which was mirrored in a strict 3D pharmacophore model. The aniline- and amide-linked conjugates moreover demonstrated greater stability in liver microsomes, while especially conjugate 21, but also 31, 43, 45, and 55 displayed excellent potency, with MRSA activities on par with 6 or better. Docking to the ribosome suggested a shifted engagement with C2469 for 21 over 6, resulting in greater multivalency, while 43/45 likely coordinates Mg2+. Lastly, conjugate 21 displayed efficacy equal to commercial Fucidin LEO (5) in a mouse Staphylococcus aureus skin infection model, highlighting its potential as a topical antibiotic lead.

MeSH terms

  • Animals
  • Anti-Bacterial Agents* / chemical synthesis
  • Anti-Bacterial Agents* / chemistry
  • Anti-Bacterial Agents* / pharmacology
  • Anti-Bacterial Agents* / therapeutic use
  • Diterpenes* / chemistry
  • Diterpenes* / pharmacology
  • Diterpenes* / therapeutic use
  • Humans
  • Methicillin-Resistant Staphylococcus aureus* / drug effects
  • Mice
  • Microbial Sensitivity Tests
  • Microsomes, Liver / metabolism
  • Molecular Docking Simulation
  • Pleuromutilins
  • Polycyclic Compounds / chemistry
  • Polycyclic Compounds / pharmacology
  • Staphylococcal Infections / drug therapy
  • Structure-Activity Relationship

Substances

  • Pleuromutilins
  • Anti-Bacterial Agents
  • Polycyclic Compounds
  • Diterpenes