Design, synthesis and biological evaluation of 2,5-dimethylfuran-3-carboxylic acid derivatives as potential IDO1 inhibitors.

•Twenty-nine new 2,5-dimethylfuran-3-carboxylic acid derivatives were designed and synthesized.•Compounds were evaluated by HeLa assay and THP-1 assay and some showed strong IDO1 inhibitory activities.•Molecular docking studies revealed that these derivatives coordinated with the heme iron by carboxylic acid.•The compound 19a (HeLa IC50 = 4.0 nM, THP-1 IC50 = 4.6 nM) exhibited no cytotoxicity and no suppression of IDO1 expression.