Compounds, compositions and methods are described for treating a CNS disorder such as a cognitive disorder, epilepsy, depression, Parkinson's disease, Alzheimer's disease, a neurodegenerative disease or neurotoxic injury. Compound of interest are 2-amino-4,5-methyleneadipic acid compounds and derivatives defined by the formula I:
wherein R¹ is selected from hydrido, alkyl, cycloalkyl, aralkyl, aryloxyalkyl, arylthioalkyl,
with each of R², R³, R⁴ and R⁵ being independently selected from hydrido, alkyl, cycloalkyl, aryl and aralkyl; wherein each of X and Y is independently selected from hydroxyl, alkoxy, alkylthio, amino and
with each of R⁶ and R⁷ being independently selected from hydrido, alkyl, cycloalkyl, aryl and aralkyl; wherein any of R¹ through R⁷ groups having a substitutable position may be substituted with one or more substituents selected from hydroxyl, halo, alkyl, haloalkyl, cyano, alkoxy, alkylthio, sulfinyl, sulfonyl, sulfinylalkyl, sulfonylalkyl, amino, acyl, acyloxy, alkoxycarbonyl and aminocarbonyl; or a pharmaceutically-acceptable salt thereof. The 2R,4S,5S isomers and the 2R,4R,5R isomers of these compounds are preferred.