Biological active polycycloalkanes. 4. Phosphoric esters of trimethylenenorbornyl alcohols

Secondary (6) and tertiary (8) phosphates of exo-5,6-trimethylenenorborn-exo-2-yl alcohol (exo-tricyclo-[5.2.1.0(2,6)]dec-exo-8-yl alcohol, 3) and a secondary ester (9) of a mixture of exo-tricyclo[5.2.1.0(2,6)]dec-3-en-8- and -9-yl alcohol (2) were prepared. The most convenient route to 6 was direct esterification of phosphoric acid with 3. 9 was obtainable by the addition of phosphoric acid to endo-dicyclopentadiene (1). These phosphates were tested in vitro for antiviral activity against Newcastle disease virus using a monolayer culture of chick embryo fibroblasts. 6 was found ca. twice more potent than, while 8 was as active as, amantadine hydrochloride under the present test conditions.