A straightforward route to enantiopure alpha-substituted derivatives of (2S,3aS,7aS)-octahydroindole-2-carboxylic acid

Ferrocene-based inhibitors of hepatitis C virus replication that target NS5A with low picomolar in vitro antiviral activity

An unprecedented series of organometallic HCV (hepatitis C virus) NS5A (nonstructural 5A protein) replication complex inhibitors that incorporates a 1,1'-ferrocenediyl scaffold was explored. This scaffold introduces the elements of linear flexibility and non-planar topology that are unconventional for this class of inhibitors. Data from 2-D NMR spectroscopic analyses of these complexes in solution support an anti (unstacked) arrangement of the pharmacophoric groups. Several complexes demonstrate single-digit picomolar in vitro activity in an HCV genotype-1b replicon system. One complex to arise from this investigation (10a) exhibits exceptional picomolar activity against HCV genotype 1a and 1b replicons, low hepatocellular cytotoxicity, and good pharmacokinetic properties in rat.

Synthesis of cis-octahydroindoles via intramolecular 1,3-dipolar cycloaddition of 2-acyl-5-aminooxazolium salts

A concise method for the diastereoselective synthesis of octahydroindoles is presented. The products contain 2-amido and 7-hydroxyl substituents. A series of 2-acyl-5-aminooxazoles were prepared in one step. Upon methylation of the oxazole nitrogen atom, the substrates underwent rapid intramolecular 1,3-dipolar cycloaddition with a tethered alkene and, after reduction with excess hydride, produced octahydroindoles with excellent diastereoselectivity. The method allows for the installation of α-quaternary stereogenic carbon atoms.