Synthesis and in vitro evaluation of S-acyl-3-thiopropyl prodrugs of Foscarnet

Harnessing radical mediated reactions of thioacids for organic synthesis

Thiyl radical mediated reactions are of burgeoning importance for organic synthesis. This Feature Article focuses specifically on thioacid- and thioacetate-derived thiyl radicals as versatile intermediates for the synthesis of a diverse range of organic compounds under mild conditions with a high degree of chemo-, regio- and diastereoselectivity. We review recent developments in the field, including novel approaches for radical initiation, strategies for the synthesis of a wide range of functional groups, peptide and glycan diversification, protein labelling and radical dethiocarboxylation. We outline our own contributions to the field over several years, including concomitant strategies to furnish native peptide bonds and discuss the future directions of this field.

Switching between P-acylation and O-acylation of H-phosphonates with chloroformates by changing acyl pyridinium and acyl ammonium ions in a microflow reactor

We report the first switchable acylation of H-phosphonate with chloroformate. The acylation site (P vs. O) in H-phosphonate was switched by changing the acyl pyridinium/ammonium ions. Unexpected phosphite formation was observed during the O-acylation of H-phosphonate. Twenty-six structurally diverse phosphotriesters and phosphonoformate esters were synthesized in microflow reactors.

Novel inhibitors of human histone deacetylases: design, synthesis, enzyme inhibition, and cancer cell growth inhibition of SAHA-based non-hydroxamates

To find novel non-hydroxamate histone deacetylase (HDAC) inhibitors, a series of compounds modeled after suberoylanilide hydroxamic acid (SAHA) was designed and synthesized. In this series, compound 7, in which the hydroxamic acid of SAHA is replaced by a thiol, was found to be as potent as SAHA, and optimization of this series led to the identification of HDAC inhibitors more potent than SAHA. In cancer cell growth inhibition assay, S-isobutyryl derivative 51 showed strong activity, and its potency was comparable to that of SAHA. The cancer cell growth inhibitory activity was verified to be the result of histone hyperacetylation and subsequent induction of p21(WAF1/CIP1) by Western blot analysis. Kinetical enzyme assay and molecular modeling suggest the thiol formed by enzymatic hydrolysis within the cell interacts with the zinc ion in the active site of HDACs.