EIF2α activator 1 (Compound 40) is an activator of eukaryotic initiation factor 2 alpha ( eIF2α ) phosphorylation. EIF2α activator 1 increases the expression level of eIF2α downstream proteins, ATF and CHOP. EIF2α activator 1 exhibits antiproliferative activity againist K562 and PBMC cells with IC 50 s of 4.00 and 19.3 μM, respectively