[Synthesis, conformation analysis, and antiviral activity of benzimidazole ribofuranosides].

To study the structure-biological effect correlation in the series of nucleoside analogues containing deazapurines, a number of 2-R-benzimidazole 1-beta-D-ribofuranosides (R = H, CF3, SCF3, CH2SCF3, CH2Ph, CH2CN) have been prepared by the modified silyl method. On the basis of CD and PMR data it was shown that the compounds exist in solution mainly as syn-conformers. Calculation of the furanose ring pseudorotation parameters in terms of N-S model indicates the predominance of S-population. In contrast to acyclonucleosides, the ribofuranosides obtained are nonactive against entheroviruses and more cytotoxic.