Synthesis and SAR study of N-(4-hydroxy-3-(2-hydroxynaphthalene-1-yl)phenyl)-arylsulfonamides: Heat shock protein 90 (Hsp90) inhibitors with submicromolar activity in an in vitro assay

Heat shock protein 90 is emerging as an important target in cancer chemotherapy. In a program directed toward identifying novel chemical probes for Hsp90, we found N-(4-hydroxy-3-(2-hydroxynaphthalene-1-yl)phenyl)benzene sulfonamide as an Hsp90 inhibitor with very weak activity. In this report, we present a new and general method for the synthesis of a variety of analogs around this scaffold, and discuss their structure–activity relationships.