6′-Methyl-5′-homoaristeromycin: A structural variation of the anti-orthopox virus candidate 5′-homoaristeromycin

The synthesis of 6′-methyl-5′-homoaristeromycin is described from a known 6′-ethyl ester. Antiviral analysis showed the (S)-6′ stereoisomer retained the vaccinia activity of the parent 5′-homoaristeromycin (1) while the (R)-6′ isomer was less active. Both were weaker than 1 towards cowpox. The diastereomers were equally active versus Epstein Barr virus while (S)-6′ was three times more active toward vesicular stomatitis virus than (R)-6′. The diastereomers were inactive towards numerous other viruses. The CC₅₀ for both diastereomers was >300 μM.