Addressing cytotoxicity of 1,4-biphenyl amide derivatives: Discovery of new potent and selective 17β-hydroxysteroid dehydrogenase type 2 inhibitors.

Four different classes of new 17β-hydroxysteroid dehydrogenase type 2 (17β-HSD2) inhibitors were synthesized, in order to lower the cytotoxicity exhibited by the lead compound A, via disrupting the linearity and the aromaticity of the biphenyl moiety. Compounds 3, 4, 7a and 8 displayed comparable or better inhibitory activity and selectivity, as well as a lower cytotoxic effect, compared to the reference compound A. The best compound 4 (IC50=160nM, selectivity factor=168, LD50≈25μM) turned out as new lead compound for inhibition of 17β-HSD2.