乙酰丙酮

3,5-dimethyl-4H-1,2-oxazol-5-ol

4-bromo-1-hydroxy-3,5-dimethyl-2-oxidopyrazol-2-ium

2-acetyl-3-methyl-2H-azirine

1-hydroxy-3,5-dimethyl-1H-pyrazole 2-oxide