title: Phosphoramidate prodrugs of (-)-β-D-(2R,4R)-dioxolane-thymine (DOT) as potent anti-HIV agents.
abstract: BACKGROUND
  Nucleoside reverse transcriptase inhibitors (NRTIs) are an effective class of agents that has played a vital role in the treatment of HIV infections. (-)-β-D-(2R,4R)-dioxolane-thymine (DOT) is a thymidine analogue that is active against wild-type and NRTI-resistant HIV-1 mutants. It has been shown that the anti-HIV activity of DOT is limited due to poor monophosphorylation.
  
  
  METHODS
  To further enhance the anti-HIV activity of DOT, an extensive structure-activity relationship analysis of phosphoramidate prodrugs of DOT monophosphate was undertaken. These prodrugs were evaluated for anti-HIV activity using Hela CD4 β-gal reporter cells (P4-CCR5 luc cells).
  
  
  RESULTS
  Among the synthesized prodrugs, the 4-bromophenyl benzyloxy l-alanyl phosphate derivative of DOT was the most potent, with a 50% effective concentration of 0.089 μM corresponding to a 75-fold increase in activity relative to the parent nucleoside DOT with no increased cytotoxicity. The metabolic stability of a selected number of potent DOT phosphoramidates was also evaluated in simulated gastric fluid, simulated intestinal fluid, human plasma and liver S9 fractions.
  
  
  CONCLUSIONS
  A series of new phosphoramidate prodrugs of DOT were prepared and evaluated as inhibitors of HIV replication in vitro. Metabolic stability studies indicated that these DOT phosphoramidate derivatives have the potential to show acceptable stability in the gastrointestinal tract, but they metabolize rapidly in the liver.
authors.affiliation: Pharmasset, Inc., Princeton, NJ, USA. peiyuan.wang@pharmasset.com
authors.forename: Peiyuan
authors.initials: P
authors.lastname: Wang
authors.forename: Suguna
authors.initials: S
authors.lastname: Rachakonda
authors.forename: Veronique
authors.initials: V
authors.lastname: Zennou
authors.forename: Meg
authors.initials: M
authors.lastname: Keilman
authors.forename: Congrong
authors.initials: C
authors.lastname: Niu
authors.forename: Donghui
authors.initials: D
authors.lastname: Bao
authors.forename: Bruce S
authors.initials: BS
authors.lastname: Ross
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Furman
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Otto
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sofia
mesh_terms: D000577:Amides / Q000494:pharmacology*; D019380:Anti-HIV Agents / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D004148:Dioxolanes / Q000737:chemistry / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010756:Phosphoric Acids / Q000494:pharmacology*; D011355:Prodrugs / Q000494:pharmacology*; D013056:Spectrophotometry, Ultraviolet; D013941:Thymine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000577:Amides; D019380:Anti-HIV Agents; D004148:Dioxolanes; D010756:Phosphoric Acids; D011355:Prodrugs; C511146:dioxolane-thymine; C011067:phosphoramidic acid; D013941:Thymine