UNC0646 (Compound 6) has high cellular potency and excellent separation of functional potency versus cell toxicity in a variety of cell lines. UNC0646 is highly potent in reducing H3K9me2 levels and has low cell toxicity. UNC0646 reduces H3K9me2 levels with ICW IC50 values of 26 nM, 10 nM, 12 nM, 14 nM, 68 nM, 86 nM and 10 nM in MDA-MB-231, MCF7, PC3, 22RV1, HCT116 wt, HCT 116 p53 and IMR90 cell lines, respectively.