5-Hydroxy-2(5H)-furanone

5-Hydroxy-2(5"H")-furanone is a furanone derived from oxidation of furfural using singlet oxygen. This oxidation is carried out generally in methanol or ethanol with a sensitizer like methylene blue or Rose bengal. The mechanism of this reaction is depicted as below.
Uses.
5-Hydroxy-2(5"H")-furanone is a potent pesticide and a four carbon building block for various heterocycles.
Chemical properties.
5-Hydroxy-2(5"H")-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.