Mono-substitution of the 2-chloro group in the core structure (compound 1) by amino-based moieties produced 2-amino-3-chloro compounds with diverse effects. Compared with the activity of compound 1, reduced activities were observed in all modified compounds in series 2-11, except for compound 4a (predicted pIC50 0.326, Table S4), which exhibited more potent activity, as indicate by a pIC50 value that was 1.08-fold greater than that of the parent compound 1 but 10.68-fold less potent than the reference drug, letrozole.