title: Synthesis and anti-HIV-1 activity of a series of 1-alkoxy-5-alkyl-6-(arylthio)uracils.
abstract: A series of 1-alkoxy-5-alkyl-6-(arylthio)uracils was synthesized and tested for their ability to inhibit HIV-1 replication. Treatment of 2-alkyl-3,3-bis(methylthio)acryloyl chlorides (5a-e) with AgOCN in benzene followed by reaction of the resulting isocyanates 6a-e with an appropriate alkoxyamine gave N-alkoxy-N'-((2-alkyl-3,3-bis(methylthio)acryloyl)ureas (10a-z) in good to excellent yields. Cyclization of 10a-z in AcOH containing a catalytic amount of p-TsOH produced 1-alkoxy-5-alkyl-6-(methylthio)uracils (11a-z). Oxidation of 11a-z with 3-chloroperoxybenzoic acid in CH2Cl2 resulted in high yields of 1-alkoxy-5-alkyl-6-(methylsulfonyl)uracils (12a-x and 12z) and 1-(benzyloxy)-6-(methylsulfinyl)thymine (12y), which were subsequently reacted with an appropriate arenethiol in ethanolic NaOH solution to afford 1-alkoxy-5-alkyl-6-(arylthio)uracils (14-49). Substitution at the 3- and 5-positions of the C-6-(phenylthio) ring by two methyl groups significantly increased its original anti-HIV-1 activity (EC50: 6-((3,5-dimethylphenyl)thio)-5-isopropyl-1-propoxyuracil (18), 0.064 microM; 6-((3,5-dimethylphenyl)thio)-1-(3-hydroxypropoxy)-5-isopropyluracil++ + (23), 0.19 microM). Among the various alkoxy substituents at the N-1, the propoxy group was the most beneficial for improving the anti-HIV-1 activity. The 1-propoxy derivative 18 proved to be the most potent inhibitor of HIV-1 replication, followed by the 1-(3-hydroxypropoxy) derivative 23. Introduction of an isopropyl group at C-5 of the uracil base also remarkably enhanced the activity. When compound 18 was incubated with a rat liver homogenate preparation, no metabolite was observed, thus confirming the metabolic stability of the N-O bond in these 1-alkoxyuracils.
authors.affiliation: Life Science Research Center, Sunkyong Industries, Kyunghi-Do, Korea.
authors.forename: D K
authors.initials: DK
authors.lastname: Kim
authors.forename: J
authors.initials: J
authors.lastname: Gam
authors.forename: Y W
authors.initials: YW
authors.lastname: Kim
authors.forename: J
authors.initials: J
authors.lastname: Lim
authors.forename: H T
authors.initials: HT
authors.lastname: Kim
authors.forename: K H
authors.initials: KH
authors.lastname: Kim
mesh_terms: D000818:Animals; D019380:Anti-HIV Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors; D015497:HIV-1 / Q000187:drug effects*; D008099:Liver / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013058:Mass Spectrometry; D051381:Rats; D017207:Rats, Sprague-Dawley; D013055:Spectrophotometry, Infrared; D013329:Structure-Activity Relationship; D014498:Uracil / Q000031:analogs & derivatives / Q000494:pharmacology*
chemical_list: D019380:Anti-HIV Agents; D014498:Uracil; D054303:HIV Reverse Transcriptase