[Nucleosides of 1,2,4-triazole: potentialities and restrictions of chemo-enzymatic method for synthesis].

The potentialities and restrictions of chemoenzymatic approach to the synthesis of new structural analogues of antiviral drug Ribavirin (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) have been determined. Syntheses of various amides of 1H-1,2,4-triazole-3-carboxylic acid and its 5-substituted analogues, prospective substrates of purine nucleoside phosphorylase (PNP), have been reported. The comparative effectiveness of the methods for obtaining amides aforementioned and also the methods for introducing functional groups to the C5 position of the heterocyclic system has been studied. New Ribavirin analogues bearing various substituents in the carboxamide group have been synthesized. The biotechnological method for the preparation of 1-beta-D-ribofuranosyl- 1,2,4-triazole-3-carbonitrile used as the intermediate in the synthesis of Viramidine, a contemporary Ribavirin analogue, has been developed.