Synthesis of a new series of phosphonylated 1,2,3-triazoles as acyclic analogs of ribavirin.

A novel series of phosphonylated 1,2,3-triazoles as structural acyclic analogs of ribavirin, in which the 1,2,3-triazole ring was substituted at C4' with COOMe, CONH2, CONHOH, and CH2 NHBoc groups, were synthesized from diethyl azidomethyl-, 2-azidoethyl-, 3-azidopropyl-, 4-azidobutyl-, 2-azido-1-hydroxyethyl-, 3-azido-2-hydroxypropyl-, 2-azidoethoxymethyl- and 2-azidoethoxyethylphosphonate. The efficient synthesis of diethyl azidomethylphosphonate from diethyl 4-nitrobenzenesulfonylmethylphosphonate employing the in situ formed azides is described. All synthesized compounds were evaluated in vitro for their inhibitory activity against a broad variety of RNA and DNA viruses. No antiviral activity was observed at 100 µM. Only compound 13g exhibited inhibitory effects on the proliferation of HeLa cells (IC50=169±45 µM).