Mechanism of electrochemical reduction of 5-thio derivatives of 2(5H)-furanone

The anionoid elimination of the substituent from position 5 of the lactone ring is the predominant pathway of electrochemical reduction of 5-arylsulfanyl- and 5-arylsulfonyl-3,4-dichloro-2(5H)-furanones in acetonitrile. The contribution of the competing elimination of the chloride ion increases on going to 3,4-dichloro-5-ethylsulfanyl-2(5H)-furanone. An experimental criterion based on the morphology of cyclic voltammograms was proposed for identification of a particular pathway of electroreduction of 2(5H)-furanone derivatives.

     

Convenient synthesis of 3,4-dichloro-5-hydroxy-2(5H)-furanone glycoconjugates

3,4-Dichloro-5-hydroxy-2(5H)-furanone treated with methyl chloroformate in the presence of diisopropylethylamine (Hünig's base) gave the corresponding carbonate. The labile methoxycarbonyloxy group smoothly undergoes substitution by amino alcohols. The obtained 5-(w-hydroxyalkylamino) mucochloric acid derivatives reacted with peracetylated glucals using triphenylphosphine hydrobromide as a catalyst to give the title muchloric acid glycoconjugates.     

Concise synthesis of chiral 2(5H)-furanone derivatives possessing 1,2,3-triazole moiety via one-pot approach

Combining three bioactive units, such as 2(5H)-furanone, 1,2,3-triazole, and amino acid together into one potential drug molecule with polyfunctional groups, a series of new chiral 2(5H)-furanone derivatives containing 1,2,3-triazole moiety have been designed and synthesized from (5S)-5-alkoxy-3,4-dibromo-2(5H)-furanones, amino acids, propargyl bromide, and organic azides via the sequential three steps, including asymmetric Michael addition–elimination, substitution, and click reaction. The latter two steps, substitution and click reaction could proceed smoothly in a one-pot process. Furthermore, the target products could be directly synthesized via a four-component one-pot approach.     

A condensed synthesis of dihydro-3(2H)-furanone

A straight forward synthesis of dihydro-3(2h)-furanone is described. An attempted preparation of the oxetan-3-one precursor 10 by this method gave, instead, the ring enlargement product 11.     

Design and synthesis of 2(5H)-furanone liquid-crystal compounds based on natural molecules and biphenyl derivatives

Starting from natural molecules, for example l-menthol and amino acids, a series of 2(5H)-furanone liquid-crystal compounds were designed, and synthesized by esterification of N-[5-menthoxy-2(5H)-furanonyl] amino acids with biphenyl-4-ol or biphenyl-4,4′-diol in the presence of dehydrating agents. The structures of all the novel compounds were confirmed by FTIR, ¹H NMR, and mass spectroscopy, and by elemental analysis. The liquid-crystal properties of the target compounds were characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and polarization optical microscopy (POM). The DSC and XRD results showed that some compounds containing short alkyl chains or with the phenyl far from the amino in the amino acid unit formed a mesomorphic phase. Products obtained from biphenyl-4,4′-diol were more likely to form a mesomorphic phase. However, POM revealed no optical texture. These investigations provide, for the first time, a basis for application of 2(5H)-furanones in liquid crystals by combination of different functional units, including biphenyl, l-menthol, and amino acids.     

A novel and practical synthetic method of 3(2H)-furanone derivatives

A novel, convenient synthetic method of 5-atyl-2,2-dimethyl-3(2H)-furanones (aryl = C₆H₅, 2-CH₃C₆H₄, 3-CH₃C₆H₄, 4-CH₃C₆H₄, 2-CIC₆H₄, 4-CIC₆H₄, 2,4-Cl₂C₆H₃) is described. It involves the Claisen-Schmidt condensation (potassium hydroxide/ethanol) of aromatic aldehydes with 3-hydroxy-3-methyl-2-butanone to give enones, whose bromination followed by alkaline hydrolysis (sodium hydroxide/ethanol) affords 3(2H)-furanone derivatives in 54–64% overall yields. The procedure is also applicable to nicotinaldehyde and furfural, although the yields are not satisfactory.     

Electrochemical synthesis of 3,5-diphenyl-2(3H)-furanone

From electrochemical reduction of phenacyl bromide, 3,5-diphenyl-2(3H)-furanone was obtained as a side-product and its structure was determined by chemical and spectral techniques.     

5-烷氧基-2(5H)-呋喃酮在有机合成中的应用

综述了国内外5-烷氧基-2（5H）-呋喃酮通过Michael加成、[3＋2]环加成、光催化加成等反应在有机合成中的应用。参考文献56篇。     

Asymmetric Diels-Alder reactions with 5-menthyloxy-2-(5H)-furanone

A new class of chiral dienophiles, 5-alkoxy-2(5H)-furanones, has been developed. Both enantiomers of 5-menthyloxy-2(5H)-ftiranone are readily available in enantiomerically pure form, starting from furfural and d- or l-menthol. Excellent diastereoselectivities (d.e. β99%) are obtained in thermal Diels-Alder reactions with several cyclic and acyclic dienes. The use of silyl dienol ethers has resulted in new routes to enantiomerically pure cyclohexanones in a highly regioselective manner.     

3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮的合成

报道了以草酸二乙酯为原料,制备具有焦糖香味的香料化合物3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮的方法:首先乙基溴化镁与草酸二乙酯通过格氏反应,以约50%产率生成2-氧代丁酸乙酯,然后其在碳酸钾的作用下发生缩合反应,以约94%产率得到3-羟基-4-甲基-5-乙基-5-乙氧羰基-2(5H)-呋喃酮,再通过水解、脱羧反应,得到3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮.路线总收率约36%.     

Phosphorylation of 3,4-Dichloro-5-hydroxy-2(5H)-furanone with Tributylphosphine

The reaction of 3,4-dichloro-5-hydroxy-2(5H)-furanone with 2 mol of tributylphosphine involves substitution of both chlorine atoms to form an unstable diphosphonium salt. The latter undergoes partial hydrolysis with cleavage of one of the P-C bonds, yielding finally a monophosphorylation product. A probable reaction pathway is considered in terms of quantum chemistry.     

The Photochemical Behaviour of 5,5-Dimethyl-2(5H)-furanone

The photochemical behaviour of the title compound 2c was investigated in various solvents. In benzene and t-butanol photodimerization affords the cis-anti-cis HH- and HT-dimers (H = head, T = tail). In acetonitrile, cyclohexane and 2-propanol, photoreduction competes with photodimerization. The photoreduction products are hydrodimers, solvent adducts and the saturated lactone (the 2H-reduction product). In acetonitrile and cyclohexane H-abstraction by the β-C-atom of the C?C bond is the predominant reduction process. In 2-propanol, solvent adducts to the α- and β-C-atoms are formed in equal amounts. In xanthone-sensitized irradiations the ratio of HH- to HT-dimer is the same as on direct irradiation and the relative rates of conversion of 2c to products in different solvents are also similar under both conditions.     

2(5H)-Furanone and 5-Hydroxy-2(5H)-furanone: Reactions and Syntheses Based on Them

Russian Journal of General Chemistry - This review summarizes the data on 2(5H)-furanone, 5-hydroxy-2(5H)-furanone, and some substituted hydrofuranones with respect to their poorly studied or...     

On the mechanism of a novel 3(2H)-Furanone-2(5H)-furanone rearrangement

The isolation of a stable intermediate product and the mechanism of a novel 3(2H)-furanone-2(5H)-furanone rearrangement that led to the facile preparation of a new class of γ-lactone amides 2 and 4 are discussed.