Identification of a potent and stable antiproliferative agent by the prodrug formation of a thiolate histone deacetylase inhibitor

To identify prodrugs of a thiolate histone deacetylase inhibitor NCH-31 that show potent antiproliferative activity and are stable in human plasma, we synthesized several candidate prodrugs of NCH-31. Among these compounds, S-2-methyl-3-phenylpropanoyl compound 2 showed more potent antiproliferative activity and higher stability in human plasma than S-isobutyryl compound NCH-51.