Identification, synthesis, and characterization of thermal degradants of brivaracetam

Imp-I∼III were observed for the first time after a 4-hour thermal degradation study of brivaracetam at 130 °C. These three degradants were prepared and purified through targeted and regiospecific synthesis, and were further characterized by 1D-NMR and 2D-NMR. After differentiation from other isomers, Imp-I was identified as (2S)-2-((3R)-2,5-dioxo-3-propylpyrrolidin-1-yl)butanamide; Imp-II was identified as (2S)-2-((3R,4S)-3-hydroxy-2-oxo-4-propylpyrrolidin-1-yl)butanamide; and Imp-III was identified as (S)-2-(2-oxo-4-propyl-2,5-dihydro-1H-pyrrol-1-yl)butanamide. Besides, in-silico toxicity prediction confirmed a high probability of non-mutagenicity of the three impurities. By preparing and characterizing the degradants, product stability of Brivaracetam under even extreme conditions was better understood, thus further ensuring product quality.