KRAS inhibitor-13 (compound 5-6) is a potent KRAS G12C inhibitor with an IC 50 of 0.883 µM. KRAS inhibitor-13 shows p-ERK inhibition activities with IC 50 s of 5.9, >100 µM in MIA PaCA-2, A549 cells, respectively. KRAS inhibitor-13 has the potential for the research of pancreatic, colorectal, and lung cancers.