5-Hydroxy-2(5H)-furanone is a furanone derived from oxidation of furfural using singlet oxygen.
5-Hydroxy-2(5H)-furanone is a potent pesticide and a four carbon building block for various heterocycles.
5-Hydroxy-2(5H)-furanone exists in chemical equilibrium with its isomer, cis-β-formylacrylic acid, in ring-chain tautomerism:
Under some conditions the compound will isomerize into succinic anhydride. Upon heating in strongly basic solution (pH > 9) this isomer will hydrate to succinic acid.