Preparation Of 5-hydroxy-2(5H) Furanone And Its Derivatives

5-Hydroxy-2?5H?furanone is a chiral compound that exists in natural products and drug structures widely.The stereo configuration of its lactone ring is closely related to the biological activity of the drug.Therefore,many derivatives containing 5-hydroxy-2?5H?furanone structures show potential synthetic and biological value.In this paper,2-furoic acid and substituted 2-furoic acid derivatives were used as substrates.5-Hydroxy-2?5H?furanone and its derivatives were successfully synthesized by photo-oxygenation reaction.5-Hydroxy-2?5H?furanone are reacted with alcohols with different carbon chains to prepare5-alkoxy-2?5H?furanone compounds.The research results obtained are as follows:Using 2-furoic acid as a substrate,the effects of photosensitizer type,solvent,substrate concentration,and photosensitizer dosage on the yield of 5-hydroxy-2?5H?-furanone were discussed.The results showed:?1?when Rose Bengal?RB?was used as the photosensitizer,in polar solvent acetonitrile,the amount of 2-furoic acid was 2g,the amount of RB was 2‰of the molar amount of the substrate,Oxygen irradiation for 9 hours,decolorization of activated carbon,The mixed product was recrystallized using a mixed solvent of ethyl acetate:petroleum ether=1:0.685.The yield of the product was 69%,and the purity of the recrystallized product was above 98%.?2?Using the same photooxygenation reaction conditions,a series of 5-hydroxy-2?5H?-furanone compounds were quickly synthesized in one step by using readily available 2-furoic acid derivatives with substituents at positions 3,4,5 of the five-membered ring.5-hydroxy-2?5H?-furanone derivatives?B₂-B₆?with yields between 57%?89%.The structures of the compounds were identified by¹H NMR and HR-MS spectroscopy.Using the ESR spin capture technology,the signal generated by the TEMP/photosensitizer/2-furoic acid/solvent/oxygen system under light conditions was measured.As a result,the characteristic triplet of the nitrogen oxide radical TEMPO was measured,indicating that the photo-oxidation activity was generated.¹O₂,¹O₂and[4+2]cycloaddition reaction with furoic acid and its derivatives,through the unstable bridged cyclic peroxide intermediate,to produce substituted 5-hydroxy-2?5H?furanone and its derivatives.?3?5-hydroxy-2-furanone as substrate was reacted with four alcohols having different carbon chain lengths to synthesize 5-alkoxy-2?5H?furanone derivatives in one step.The yield of the product was between 20.7%?68.9%,short-chain methoxy derivatives are better water-soluble,and long-chain butoxy,n-octyloxy,and n-decoxy compounds are poorly water-soluble.It is expected to have new applications as surfactants value.