6,7-二氢-2-甲基苯并[d]噁唑-4(5h)-酮

2-酮环戊烷-1-甲酸苄胺

3,5,6,7-Tetrahydro-1-benzofuran-2,4-dione

2-氧代环戊烷羧酸甲酯

2-(oxomethylidene)cyclopentan-1-one