methyl (2S)-2-pyrrolidinecarboxylate

L-脯氨酸

4-氧杂-4,5,6,7-四氢苯并[B]呋喃-3-羧酸

3-hydroxy-4-oxo-2,3,4,5,6,7-hexahydrobenzofuran-3-carboxylic acid ethyl ester

1,3-环己二酮