Synthesis and SAR study of novel diimide skeleton compounds with the anti-inflammatory activities in vitro and in vivo

•The carboxylic acid is condensed with a weakly active amide to form a new diimide functional group through CDI and NaH.•26 diimide compounds were synthesized and evaluated for the anti-inflammatory activity.•Compound 4d has good anti-inflammatory activity, and the IC50 of IL-6 reached 1.59 μM.•Compound 4d may be a potential anti-inflammatory lead candidate for the treatment of ALI and sepsis.