Prodrugs of the Phosphoribosylated Forms of Hydroxypyrazinecarboxamide Pseudobase T-705 and Its De-Fluoro Analogue T-1105 as Potent Influenza Virus Inhibitors

J Med Chem. 2018 Jul 26;61(14):6193-6210. doi: 10.1021/acs.jmedchem.8b00617. Epub 2018 Jul 3.

Abstract

We here disclose chemical synthesis of ribonucleoside 5'-monophosphate (RMP), -diphosphate (RDP), and -triphosphate (RTP) and cycloSal-, Di PPro-, and Tri PPPro nucleotide prodrugs of the antiviral pseudobase T-1105. Moreover, we include one nucleoside diphosphate prodrug of the chemically less stable T-705. We demonstrate efficient T-1105-RDP and -RTP release from the Di PPro and Tri PPPro compounds by esterase activation. Using crude enzyme extracts, we saw rapid phosphorylation of T-1105-RDP into T-1105-RTP. In sharp contrast, phosphorylation of T-1105-RMP was not seen, indicating a yet unrecognized bottleneck in T-1105's metabolic activation. Accordingly, Di PPro and Tri PPPro compounds displayed improved cell culture activity against influenza A and B virus, which they retained in a mutant cell line incapable of activating the nucleobase parent. T-1105-RTP had a strong inhibitory effect against isolated influenza polymerase, and Di PPro-T-1105-RDP showed 4-fold higher potency in suppressing one-cycle viral RNA synthesis versus T-1105. Hence, our T-1105-RDP and -RTP prodrugs improve antiviral potency and achieve efficient metabolic bypass.

MeSH terms

  • Amides / chemistry*
  • Amides / metabolism
  • Amides / pharmacology*
  • Animals
  • Antiviral Agents / chemistry
  • Antiviral Agents / metabolism
  • Antiviral Agents / pharmacology
  • Dogs
  • Madin Darby Canine Kidney Cells
  • Orthomyxoviridae / drug effects*
  • Prodrugs / metabolism*
  • Pyrazines / chemistry*
  • Pyrazines / metabolism
  • Pyrazines / pharmacology*
  • Ribonucleotides / chemistry*

Substances

  • Amides
  • Antiviral Agents
  • Prodrugs
  • Pyrazines
  • Ribonucleotides
  • T 1105
  • favipiravir