3. Structures, In Vitro Inhibitory Potencies and Selectivity towards hBChE of Lead Compound 2, Racemic Compound 3, and Compounds (S)-(+)-3 and (R)-(−)-3 .

^aThe values are expressed as mean ± SEM of at least two independent experiments.

^bSR, selectivity ratio: IC₅₀(hAChE)/IC₅₀(hBChE).