ethyl 2-methyl-4-oxo-3H-pyran-2-carboxylate

3-羟基二苯并呋喃

4-oxocyclohexene-1-carbonitrile

methyl 2-(1-chlorocyclopropyl)-4-hydroxybenzoate

2-(2-phenylethenyl)-2,3-dihydropyran-4-one