KRAS G12D inhibitor 3 is a KRAS G12D inhibitor with an IC 50 of <500 nM. KRAS G12D inhibitor 3 has antitumor effects (WO2022002102A1; compound 146). KRAS G12D inhibitor 3 is a click chemistry reagent, it contains an Alkyne group and can undergo copper-catalyzed azide-alkyne cycloaddition (CuAAc) with molecules containing Azide groups.