Fluorinated methylenecyclopropane analogues of nucleosides. Synthesis and antiviral activity of (Z)- and (E)-9-{[(2-fluoromethyl-2-hydroxymethyl)-cyclopropylidene]methyl}adenine and -guanine

Article abstract of DOI:10.1016/j.bmc.2007.11.082

Synthesis and antiviral activity of the title fluoromethylenecyclopropane analogues 15a, 15b, 16a, and 16b is described. Methylenecyclopropane carboxylate was first transformed to 2,2-bis-hydroxymethylmethylenecyclopropane. Selective monoacetylation followed by introduction of fluorine gave 2-acetoxymethyl-2-fluoromethylmethylenecyclopropane as the key intermediate. The synthesis of analogues 15a, 15b, 16a, and 16b then followed alkylation-elimination procedure as described previously for other methylenecyclopropane analogues. The adenine Z-isomer 15a was found to be a potent inhibitor of Epstein-Barr virus (EBV) in vitro with EC₅₀/CC₅₀ (μM) 0.5/55.7. Compounds 15b, 16a, and 16b were also active but at higher concentrations, EC₅₀/CC₅₀ (μM) 3.2-7.5/53.6-64.1. Analogue 15a inhibited hepatitis C virus by virtue of its cytotoxicity and it moderately inhibited replication of the Towne strain of human cytomegalovirus (HCMV). The E-isomer 16a was a substrate for adenosine deaminase, whereas the Z-isomer 15a was not deaminated.