DL-脯氨酸

optically inactive (3,6-dioxo-piperazine-2,5-diyl)-di-acetic acid diamide

1-amino-ethane-1,1,2,2-tetracarboxylic acid tetraethyl ester

对硝基甲苯

N-[(3S)-2,5-dioxooxolan-3-yl]benzamide