Likewise, the substitution of the 2-chloro group on the naphthoquinone ring by an amino alkyl chain can reduce the activity of the compound, as observed for compound 2 (Table S3, Panel 1). The conversion of the N-alkyl chain of compound 2 to an N-alkylphenyl group afforded compound 10 with an increased G1v value but decreased Mor04m and Mor08e values that improved the activity of the compound. On the other hand, the introduction of diOCH3 into the terminal phenyl ring of compound 10 yielded inactive compound 11 with a decreased G1v value. Interestingly, compound 10 (IC50 = 3.3 µM) exhibited relatively high and comparable activity to that of compound 6 (IC50 = 3.1 µM). This finding could be attributed to the flexible ethyl phenyl group on the 2-amino position of compound 10 (low Mor08e or electron-donating effect but high G1v values) that causes the molecule to exist in a more favorable form when interacting with the target site. In contrast, the diOCH3 groups of compound 11 might produce a bulky molecule that is unfavorable for exerting the activity. N-anilinyl analog 9 (Table S3, Panel 8) showed a lower Mor08e value (-1.001) but a higher G1v value (0.179) than did N-phenyl analog 3 (Mor08e = -0.494, G1v = 0.169), thereby giving rise to more potent activity for the former.