9-(Hydroxyethyloxymethyl)guanine (acyclovir) phosphite and fluorophosphate were synthesized by the reactions of acyclovir with phosphorus trichloride in triethyl phosphate and with fluorophosphoric acid in the presence of 2,4,6-triisopropylbenzenesulfonyl chloride, respectively, and characterized by the data of 1H and 31P NMR and mass spectra. These products selectively inhibit reproduction of the herpes simplex virus type 1 in the Vero cell culture, the phosphite being also substantially active against a herpes virus strain resistant to acyclovir.
