© 2017 Elsevier Ltd Many forms of solid tumor have a characteristic feature known as hypoxia, which describes a low or non-existent presence of oxygen in the cellular microenvironment. This decrease in oxygen causes activation of the hypoxia inducible factor (HIF) pathway, which activates the transcription of many genes that cause cell proliferation, metastasis, increased glycolysis and angiogenesis. Increased HIF expression has been linked with poor patient prognosis, increased malignancy, and therapeutic resistance. Previous work in our lab has identified 1 and 2 as inhibitors of the HIF pathway, specifically as disrupters of the p300-HIF-1α complex formation. A library of sulfonamide analogs has been designed and synthesized with the intent of examining the SAR of this series of compounds and improving potency and physicochemical properties as compared with lead compounds 1 and 2. At the end, we have achieved a thorough understanding of the structural features critical for future optimization work.