Among them, 2-methoxyethoxy-substituted analogue 61 (Figure 29) was found to be the most potent HDAC1 inhibitor (IC50 = 0.30 nM) with significant growth inhibition against human MDA-MB-231, H157, and A549 cancer cell lines (IC50 = 0.36–2.79 μM), even better than SAHA (IC50 = 0.36–2.79 μM). Here, HDAC1 is linked to cancer.