Total synthesis of bicyclic depsipeptides spiruchostatins C and D and investigation of their histone deacetylase inhibitory and antiproliferative activities

摘要

The bicyclic depsipeptide histone deacetylase (HDAC) inhibitors spiruchostatins C and D were synthesized for the first time in a highly convergent and unified manner. The method features the amide coupling of a d-leucine-d-cysteine- or d-valine-d-cysteine-containing segment with a d-alanine- or d-valine-containing segment to directly assemble the corresponding seco-acids, key precursors of macrolactonization. The HDAC inhibitory assay and cell-growth inhibition analysis of the synthesized depsipeptides determined the order of potency of spiruchostatins A-D in comparison with the clinically approved depsipeptide FK228 (romidepsin). Novel aspects of structure-activity relationships (SAR) were revealed.