Nonsteroidal aromatase inhibitor 1 (Compound 13h) is a nonsteroidal aromatase ( CYP19A1 ) inhibitor ( IC 50 =0.09 nM). Nonsteroidal aromatase inhibitor 1 has potential for breast cancer research. Nonsteroidal aromatase inhibitor 1 is a click chemistry reagent, it contains an Alkyne group and can undergo copper-catalyzed azide-alkyne cycloaddition (CuAAc) with molecules containing Azide groups.