(2R)?-Propyl-?butanedioic Acid 4-?(1,?1-?Dimethylethyl) Ester is an intermediate in synthesizing Brivaracetam-d7 (B677647). It is a labeled analogue of Brivaracetam, which is a 4-n-propyl analog of levetiracetam (L331500). It is also a racetam derivative with anticonvulsant properties.