4-(3-acetylanilino)-4-oxobutanoic acid

2-(2,5-二氧代-2,5-二氢-吡咯-1-基)-丙酸

4-(N-methylanilino)-4-oxobut-2-enoic acid

cyclohept-6-ene-1,3,5-trione

2-Acetyl-cyclopent-4-en-1.3-dion