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DOI: 10.1055/s-0032-1317782
Chemo-Enzymatic Synthesis and Biological Evaluation of 5,6-Disubstituted Benzimidazole Ribo- and 2′-Deoxyribonucleosides
Publication History
Received: 11 October 2012
Accepted after revision: 16 November 2012
Publication Date:
07 December 2012 (online)
Abstract
A number of new 5,6-disubstituted benzimidazoles have been prepared and their substrate properties for recombinant E. coli purine nucleoside phosphorylase (PNP; the product of the deoD gene) in the transglycosylation reaction were investigated. The heterocyclic bases showed good substrate activity for PNP and the ribo- and 2′-deoxyribonucleosides were synthesized. The predominant (OMe and OEt) or exclusive (Oi-Pr, morpholino, and N-methylpiperazino) formation of the 5-substituted 6-fluoro-1-(β-d-ribofuranosyl)benzimidazoles was observed. The formation of the regioisomeric 6- methoxy-, 6-ethoxy-, or 6-isopropoxy-substituted 1-(2-deoxy-β-d-ribofuranosyl)-5-fluorobenzimidazoles was observed in the trans-2-deoxyribosylation reaction of the corresponding bases. The predominant or exclusive formation of the regioisomeric N 1-nucleosides with bulky 5-substituents of 6-fluorobenzimidazole points to a large hydrophobic pocket in the E. coli PNP active site that can accommodate these groups. The biological activity of the synthesized nucleosides was studied and revealed no inhibitory activity against a broad variety of DNA and RNA viruses. The compounds also lacked significant cytotoxicity.