title: Lipophilic phosphoramidates as antiviral pronucleotides.
abstract: In order to overcome restrictions imposed by activation (phosphorylation) mechanism of antiviral and antitumor nucleoside analogues several prodrug approaches have been designed. Lipophilic pronucleotides are capable of intracellular delivery of monophosphates of nucleoside analogues, thus circumventing the limitations of enzymic phosphorylation. One of the successful approaches employs lipophilic amino acid ester (alanine) phenyl phosphoramidates as pronucleotides. This approach was applied to AIDS drugs such as AZT, d4T and related analogues but also to nonclassical nucleoside analogues based on allenic and methylenecyclopropane structure. Antiviral effects of the parent analogues were in many cases increased by conversion to phenyl phosphoralaninate (PPA) pronucleotides. Although cytotoxicity increase frequently accompanies antiviral effects of these pronucleotides, a favorable selectivity index can be obtained by manipulation of the parent structure as shown, e.g., for 2,6-diaminopurine methylenecyclopropane pronucleotide 15c. A lack of in vivo toxicity was demonstrated for 2-amino-6-methoxypurine methylenecyclopropane pronucleotide 15e in mice. The PPA pronucleotides can overcome deficiency of phosphorylating enzymes and offer favorable cross-resistance patterns when compared with other antiviral drugs.
authors.affiliation: Department of Chemistry, Developmental Therapeutics Program, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, 110 E. Warren Ave., Detroit, MI 48201-1379, USA. zemlicka@kci.wayne.edu
authors.forename: Jiri
authors.initials: J
authors.lastname: Zemlicka
mesh_terms: D000577:Amides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D019380:Anti-HIV Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000998:Antiviral Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D015195:Drug Design; D006678:HIV / Q000187:drug effects; D006801:Humans; D015394:Molecular Structure; D009711:Nucleotides / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D010756:Phosphoric Acids / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D010766:Phosphorylation; D011355:Prodrugs / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D000577:Amides; D019380:Anti-HIV Agents; D000998:Antiviral Agents; D009711:Nucleotides; D010756:Phosphoric Acids; D011355:Prodrugs