DDQ/Fe(NO3)3-Catalyzed Aerobic Synthesis of 3-Acyl Indoles and an In Silico Study for the Binding Affinity of N-Tosyl-3-acyl Indoles toward RdRp against SARS-CoV-2

J Org Chem. 2023 Jan 20;88(2):838-851. doi: 10.1021/acs.joc.2c02009. Epub 2023 Jan 9.

Abstract

In the present study, we herein report a DDQ-catalyzed new protocol for the synthesis of substituted 3-acylindoles. Being a potential system for virtual hydrogen storage, introduction of catalytic DDQ in combination with Fe(NO3)3·9H2O and molecular oxygen as co-catalysts offers a regioselective oxo-functionalization of C-3 alkyl-/aryllidine indolines even with scale-up investigations. Intermediate isolation, their spectroscopic characterization, and the density functional theory calculations indicate that the method involves dehydrogenative allylic hydroxylation and 1,3-functional group isomerization/aromatization followed by terminal oxidation to afford 3-acylindoles quantitatively with very high regioselectivity. This method is very general for a large number of substrates with varieties of functional groups tolerance emerging high-yield outcome. Moreover, molecular docking studies were performed for some selected ligands with an RNA-dependent RNA polymerase complex (RdRp complex) of SARS-CoV-2 to illustrate the binding potential of those ligands. The docking results revealed that few of the ligands possess the potential to inhibit the RdRp of SARS-Cov-2 with binding energies (-6.7 to -8.19 kcal/mol), which are comparably higher with respect to the reported binding energies of the conventional re-purposed drugs such as Remdesivir, Ribavirin, and so forth (-4 to -7 kcal/mol).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antiviral Agents / chemistry
  • Antiviral Agents / pharmacology
  • COVID-19*
  • Humans
  • Indoles / pharmacology
  • Ligands
  • Molecular Docking Simulation
  • RNA-Dependent RNA Polymerase / chemistry
  • RNA-Dependent RNA Polymerase / genetics
  • RNA-Dependent RNA Polymerase / metabolism
  • SARS-CoV-2*

Substances

  • Ligands
  • Antiviral Agents
  • RNA-Dependent RNA Polymerase
  • Indoles