title: Phenylselenenyl- and phenylthio-substituted pyrimidines as inhibitors of dihydrouracil dehydrogenase and uridine phosphorylase.
abstract: Lithiation of 5-bromo-2,4-bis(benzyloxy)pyrimidine (3) with n-BuLi at -80 degrees C followed by the addition of diphenyl diselenide or diphenyl disulfide as an electrophile furnished the corresponding 5-(phenylhetera)-2,4-bis(benzyloxy)pyrimidine, which on exposure to trimethylsilyl iodide in CH2-Cl2 at room temperature yielded the 5-(phenylhetera)uracils in 70-75% yield. Similarly, the 6-(phenylhetera)uracils were prepared from 6-bromo-2,4-bis(benzyloxy)pyrimidine (10). 1-[(2-Hydroxyethoxy)methyl]-5-(phenylselenenyl)uracil (PSAU, 18) and 1-(ethoxymethyl)-5-(phenylselenenyl)uracil (17) were synthesized by the electrophilic addition of benzeneselenenyl chloride to the acyclic uracils under basic conditions. These compounds were evaluated for their ability to inhibit dihydrouracil dehydrogenase (DHUDase, E.C. 1.3.1.2), orotate phosphoribosyltransferase (OPRTase, E.C. 2.4.2.10), uridine phosphorylase (UrdPase, E.C. 2.4.2.3), and thymidine phosphorylase (dThdPase, E.C. 2.4.2.4). 5-(Phenylselenenyl)uracil (PSU, 6) and 5-(phenylthio)uracil (PTU, 7) inhibited DHUDase with apparent K(i) values of 4.8 and 5.4 microM, respectively. The corresponding 6-analogues, compounds 13 and 14, demonstrated inhibitory activity against OPRTase. PTU as well as PSU and its riboside, 2'-deoxyriboside, and acyclonucleosides were inhibitors of UrdPase, with PSAU (18) being the most potent with an apparent K(i) value of 3.8 microM. None of the compounds evaluated had any effect on dThdPase. Interestingly, most of the compounds showed modest selective anti-human-immunodeficiency-virus activity in acutely infected primary human lymphocytes.
authors.affiliation: Veterans Affairs Medical Center (Atlanta), Decatur, Georgia 30033.
authors.forename: N M
authors.initials: NM
authors.lastname: Goudgaon
authors.forename: F N
authors.initials: FN
authors.lastname: Naguib
authors.forename: M H
authors.initials: MH
authors.lastname: el Kouni
authors.forename: R F
authors.initials: RF
authors.lastname: Schinazi
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D050744:Dihydrouracil Dehydrogenase (NAD+); D004220:Disulfides / Q000737:chemistry; D005260:Female; D015497:HIV-1 / Q000187:drug effects; D006801:Humans; D008099:Liver / Q000201:enzymology; D008214:Lymphocytes / Q000382:microbiology; D051379:Mice; D016566:Organoselenium Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D010088:Oxidoreductases / Q000037:antagonists & inhibitors*; D044925:Oxidoreductases Acting on CH-CH Group Donors; D011743:Pyrimidines / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D012643:Selenium / Q000737:chemistry; D014498:Uracil / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D014543:Uridine Phosphorylase / Q000037:antagonists & inhibitors*
chemical_list: D004220:Disulfides; D016566:Organoselenium Compounds; D011743:Pyrimidines; C085082:1-((2-hydroxyethoxy)methyl)-5-(phenylselenenyl)uracil; D014498:Uracil; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; D050744:Dihydrouracil Dehydrogenase (NAD+); D014543:Uridine Phosphorylase; D012643:Selenium