Compound 2a (Figure 2) displayed a better inhibition rate (96.7%) than flavopiridol (90.0%) against MCF-7 tumor cell proliferation at a concentration of 50 μg/ml, and comparable to CGP74514A (Figure 2), a selective CDK1 inhibitor (96.7%) (Mou et al., 2021a). This evidence concerns the gene CDK1 and neoplasm.