(S)-N-(1-氨基-1-氧代丁-2-基)-4-氯丁酰胺

(S)-2-(2-oxopyrrolidin-1-yl)butanoyl chloride

1-((S)-1-羟基丁烷-2-基)吡咯烷-2-酮

alpha-乙基-2-氧代-1-吡咯烷乙酸