Synthesis and anti-HIV activity of several 2'-fluoro-containing pyrimidine nucleosides

Article abstract of DOI:10.1021/jm00170a017

Several 2'-fluoroarabino-2',3'-dideoxy- and 2'-fluoro-2',3'-unsaturated 2',3'-dideoxy pyrimidine nucleoside analogues are reported. The saturated analogues 1-(2,3-dideoxy-2-fluoro-β-D-threo-pentofuranosyl)thymine (2'-threo-FddT, 33), 1-(2,3-dideoxy-2-fluoro-β-D-threo-pentofuranosyl)uracil (2'-threo-FddU, 22) were readily prepared from the corresponding 2'-deoxy-2'-fluoroarabinosyl nucleoside analogue by radical deoxygenation of the 3'-OH. The unsaturated compounds 1-(2,3-dideoxy-2-fluoro-β-D-glycero-pent-2-enofuranosyl)thymine (2'-Fd4T, 40) and 1-[5-O-(monomethoxytrityl)-2-fluoro-2,3-dideoxy-β-D-glycero -pent-2-enofuranosyl]uracil (39) were synthesized by an elimination reaction of the O-2,3'-anhydro-2'-fluoro-lyxo derivatives under basic conditions. The cytidine analogues 28 and 41 were prepared by amination of the corresponding uridine derivatives; compounds 28 and 41 were deprotected to give 1-(2,3-dideoxy-2-fluoro-β-D-arabinofuranosyl)cytidine (2'-threo-FddC, 29) and 1-(2,3-dideoxy-2-fluoro-β-D-glycero-pent-2-enofuranosyl)cytosine (2'-Fd4C, 42), respectively. All of these novel compounds were evaluated in vitro against human immunodeficiency virus (HIV) (LAV isolate). 2'-threo-FddC (29) was the most active of the newly synthesized substances against HIV with an ID₅₀ of 0.8 μg/mL; ddC had an ID₅₀ of 0.007 μg/mL. Because of its potency in the initial tests, 29 was further evaluated in both T cells and macrophage/monocyte cell lines, with several different isolates of HIV. Although 2'-threo-FddC (29) exhibited good antiviral activity in these systems, it was less active than AZT in these assays. At 1 μM the inhibition of CFU-GM by 29 was found to be 35-40%; this is slightly higher than seen with AZT.