Table 1. Structure and Activities of Compounds 7–20 Evaluated by an Enzymatic Assay.

^aInh %: inhibition percentage at 100 μM concentration.

^bIC₅₀: measured in μM by an enzymatic assay from an average of three experiments. IC₅₀ values were determined for compounds that showed >90% inhibition at 100 μM.

^cLE was calculated using the equation: LE = (1.37 × pIC₅₀)/HA, where HA means heavy atom, i.e., a non-hydrogen atom. LE: compound 14 = 0.29; compound 19 = 0.31.