Structure-based design, synthesis and evaluation of 2,4-diaminopyrimidine derivatives as novel caspase-1 inhibitors

Interleukin-1β converting enzyme contributes in various inflammatory and autoimmune diseases by maturing pro-inflammatory cytokines IL-1β, IL-18 and IL-33. Therefore, inhibition caspase-1 may provide a potential therapeutic strategy for the treatment of chronic inflammatory diseases. Here we have reported structure-based design, synthesis and biological evaluation of 2,4-diaminopyrimidine derivatives (6a-6w) as potential caspase-1 inhibitors. Six compounds 6m, 6n, 6o, 6p, 6q and 6r showed significant enzymatic inhibition with IC₅₀ ranging from 0.022 to 0.078 µM. These compounds also displayed excellent cellular potency at sub-micromolar concentration. Moreover, molecular docking studies provided the useful binding insights specific for caspase-1 inhibition. All these results indicated that compounds 6m, 6n and 6o could be potential leads for the development of newer caspase-1 inhibitors as anti-inflammatory agents.