Design, synthesis and antiviral evaluation of 2'-C-methyl branched guanosine pronucleotides: the discovery of IDX184, a potent liver-targeted HCV polymerase inhibitor.

Background: Ribonucleoside analogs possessing a β-methyl substituent at the 2'-position of the d-ribose moiety have been previously discovered to be potent and selective inhibitors of hepatitis C virus (HCV) replication, their triphosphates acting as alternative substrate inhibitors of the HCV RdRp NS5B. Results/methodology: In this article, the authors detail the synthesis, anti-HCV evaluation in cell-based replicon assays and structure-activity relationships of several phosphoramidate diester derivatives of 2'-C-methylguanosine (2'-MeG).

Conclusion: The most promising compound, namely the O-[S-(hydroxyl)pivaloyl-2-thioethyl]{abbreviated as O-[(HO)tBuSATE)]} N-benzylamine phosphoramidate diester derivative (IDX184), was selected for further in vivo studies, and was the first clinical pronucleotide evaluated for the treatment of chronic hepatitis C up to Phase II trials.

Synthesis of the first example of a nucleoside analogue bearing a 5'-deoxy-beta-D-allo-septanose as a seven-membered ring sugar moiety.

The first example of a nucleoside analogue bearing a 5'-deoxy-beta-D-allo-septanose as a seven-membered ring sugar moiety, namely 9-(5-deoxy-beta-D-allo-septanosyl)-adenine, is reported. This compound was synthesized in 14 steps from the commercially available D-glycero-D-gulo-1,4-lactone. When evaluated in cell culture experiments against a broad range of viruses, it did not exhibit any significant antiviral effect or cytotoxicity.

Synthesis and antiviral evaluation of a seven-membered sugar ring nucleoside analog, 9-(5-deoxy-beta-D-allo-septanosyl)-adenine.

The first example of a nucleoside analogue bearing a 5'-deoxy-beta-D-allo-septanose as the sugar moiety was synthesized and evaluated as a potential inhibitor of several virus replication.