Halogen-substituted catechol bisphosphates are potent and selective inhibitors of the transcription factor STAT5b

The transcription factor STAT5b is an antitumor target. Recently, we presented the small molecules Stafib-1 and Stafib-2 as potent, selective inhibitors of the STAT5b SH2 domain. Here we report that halogen substitutions on the terminal phenyl ring of Stafib-1 and a close derivative are tolerated and specificity over the STAT5a SH2 domain is maintained, albeit with a slight reduction in activity. Our data demonstrate that the synthetic methodology used for generating Stafib-1 and Stafib-2 can be utilized to synthesize a small library of halogen-substituted derivatives, and extend the panel of catechol bisphosphate-based submicromolar and selective STAT5b inhibitors.