Ethyl 3-methyl-4,5,6,7-tetrahydro-1H-indole-2-carboxylate

2-O-ethyl 4-O-methyl 3,5-dimethyl-1H-pyrrole-2,4-dicarboxylate

3,5-二甲基-1H-吡咯-2-甲酸乙酯

DL-2-氨基丁酸

1-哌啶羧酸乙酯