Potent and selective inhibition of human immunodeficiency virus type 1 (HIV-1) by 5-ethyl-6-phenylthiouracil derivatives through their interaction with the HIV-1 reverse transcriptase

Proc Natl Acad Sci U S A. 1991 Mar 15;88(6):2356-60. doi: 10.1073/pnas.88.6.2356.


In the search for 1-[(2-hydroxyethoxy)-methyl]-6-(phenylthio)thymine (HEPT) derivatives, we have found several 5-ethyl-6-(phenylthio)uracil analogues to be highly potent and selective inhibitors of human immunodeficiency virus (HIV) type 1. 1-Benzyloxymethyl-5-ethyl-6-phenylthiouracil, the most potent congener of the series, inhibits HIV-1 replication in a variety of cell systems, including peripheral blood lymphocytes, at a concentration of 1.5-7.0 nM, which is lower by a factor of 10(3) than the 50% antivirally effective concentration of the parent compound HEPT. The 5-ethyl-6-(phenylthio)uracil analogues, like HEPT itself, do not inhibit HIV-2 replication but do inhibit replication of 3'-azido-3'-deoxythymidine-resistant mutants of HIV-1. 1-Benzyloxy-methyl-5-ethyl-6-phenylthiouracil and its congeners are targeted at the HIV-1 reverse transcriptase (RT). They do not inhibit HIV-2 RT. They do not need to be metabolized to exert their inhibitory effect on HIV-1 RT. Yet this inhibitory effect is competitive with the natural substrate dTTP. The HEPT derivatives represent a group of RT inhibitors with a unique mode of interaction with HIV-1 RT.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antiviral Agents / pharmacology*
  • Cell Line
  • Cells, Cultured
  • HIV-1 / drug effects*
  • HIV-1 / enzymology
  • HIV-2 / drug effects
  • Humans
  • Kinetics
  • Recombinant Proteins / antagonists & inhibitors
  • Reverse Transcriptase Inhibitors*
  • Structure-Activity Relationship
  • Thymine / analogs & derivatives*
  • Triazoles / pharmacology*


  • Antiviral Agents
  • Recombinant Proteins
  • Reverse Transcriptase Inhibitors
  • Triazoles
  • 4-(hydroxy-3-piperidylpropyl)-5-methyl-2-phenyltriazole
  • Thymine