5-氧代戊酸乙酯

3-(4-甲基苯基)-6,7,8,9-四氢-5H-苯并-5-环庚酮酮

ethyl 5-amino-5-oxopentanoate

diethyl 2-acetyl-3-oxoheptanedioate

5-O-ethyl 1-O-methyl pentanedioate