The chiral title compounds 2--11 were assessed for their potential anti-Parkinsonian, antipsychotic, and anticonvulsant properties. The most striking differences in the biological activity of enantiomeric pairs were noted for D-(R)-2-amino-N-(3,4-methylenedioxyphenyl)succinimide hydrochloride (2) vs. L-(S)-3 and D-(R)-2-amino-N-(3,4-isopropylidenedioxyphenyl)succinimide (4) vs. L-(S)-5. D-(R)-2-partially attenuated amphetamine-induced stereotyped behavior, whereas D-(R)-4 antagonized oxotremorine-induced tremors. Their respective enantiomorphs were inactive in these tests. No differences in anticonvulsant potency of enantiomeric pairs were observed. The stereoselective actions of D-(R)-2 and 4 were rationalized on the basis of the presence or absence of gem-dimethyl functions in isopropylidenedioxy vs. methylenedioxy groups; the data seem to indicate that these methyl groups influence selective receptor site interaction in the D-(R) series.