- Distribution and organoleptic impact of sotolon enantiomers in dry white wines
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The enantiomers of sotolon, a flavor compound typical of oxidized white wines, were separated by preparative HPLC to determine their perception thresholds and distribution in wines. The enantiomeric ratios of chiral sotolon were evaluated in several dry white wines using gas chromatography and a chiral column (β-cyclodextrin) connected to a 2 m precolumn (BP20). The perception threshold of (S)-sotolon (0.8 μg/L) in model wine solution was 100 times lower than that of the (R) form (89 μg/L), indicating that (S)-sotolon contributes to the characteristic aroma of prematurely aged dry white wines. Both enantiomers are detected in white wines. Analysis of commercial dry white wines from various vintages and origins revealed three types of distribution patterns: the racemic form, an excess of R, and an excess of S. The proportions found in these wines may be partially explained by the slow racemization kinetics (20 months) of optically active sotolon.
- Pons, Alexandre,Lavigne, Valerie,Landais, Yannick,Darriet, Philippe,Dubourdieu, Denis
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- Synthesizing method for dimethyl-3-hydroxy-2,5-dihydrofuran-2-one spice
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The invention discloses a synthesizing method for dimethyl-3-hydroxy-2,5-dihydrofuran-2-one spice, and relates to the technical field of specie synthesis. According to the synthesizing method, the dimethyl-3-hydroxy-2,5-dihydrofuran-2-one is obtained by taking diethyl oxalate as a starting material, preparing 2-oxo-ethyl butyrate through a Grignard reaction in the absence of water and under the protection of nitrogen; cyclizing a required carbon skeleton under the action of potassium carbonate and acetaldehyde to obtain the dimethyl-3-hydroxy-2,5-dihydrofuran-2-one. A reaction solvent and an extracting agent can be used after being recycled; the process flow is reduced; the reaction yield is relatively high.
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Paragraph 0053-0060
(2019/10/23)
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- Production method of dimethylhydroxyfuranone synthetic perfume
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The invention discloses a production method of dimethylhydroxyfuranone synthetic perfume, and relates to the technical field of perfume production. The production method comprises the steps that anhydrous tetrahydrofuran is taken as a solvent, diethyl oxalate is subjected to Grignard reaction under the nitrogen protection condition, after extracting and washing through dichloromethane and drying through anhydrous sodium sulfate, the dichloromethane is recovered to be applied, and decompressed distillation is conducted to collect 2-ethyl oxybutyrate; and then absolute ethyl alcohol is taken asa solvent, the 2-ethyl oxybutyrate is cyclized under the effects of potassium carbonate and acetaldehyde, ethyl alcohol is recovered at the normal pressure, after extracting and washing through the dichloromethane and drying through the anhydrous sodium sulfate, the dichloromethane is recovered to be applied, decompressed distillation is conducted, and thus a dimethylhydroxyfuranone synthetic perfume product is obtained. The production method is clear in process control parameter and good in process repeatability, the solvent is reasonably recovered and reutilized, the production cost is lowered while environment pollution is reduced, the obtained product, namely the dimethylhydroxyfuranone synthetic perfume, is high in yield and purity, and the perfume requirements are met.
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Paragraph 0036; 0048-0057; 0069-0077
(2019/11/12)
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- Formation of 3-hydroxy-4,5-dimethyl-2(5H)-furanone (sotolone) from 4-hydroxy-L-isoleucine and 3-amino-4,5-dimethyl-3,4-dihydro-2(5H)-furanone
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The proposed formation of 3-hydroxy-4,5-dimethyl-2(5H)-furanone (sotolone) from 4-hydroxy-L-isoleucine (1) and the corresponding lactone 3-amino-4,5-dimethyl-3,4-dihydro-2(5H)-furanone (2) by thermally induced oxidative deamination was corroborated. The formation of sotolone was studied in model systems by reacting 1 or 2 with different carbonyl compounds in a phosphate buffer at pH 5 at 100 °C for 1 h. The amount of sotolone was quantified by stable isotope dilution assays using 13C2-labeled sotolone as internal standard and GC-MS operating in the selected ion monitoring mode. In general, a-ketoaldehydes were found to be more reactive than a-diketones. Methylglyoxal gave rise to about 64 μg sotolone per mg 1 (7.4 mol %) compared to less than 1μg (0.1 mol %) when reacted with 2,3-pentanedione. Using 2 as the starting material, the yields were increased to 274 μg (35.9 mol %) and 5.4 μg (0.7 mol %), respectively. The optimum pH of the reaction with HIL was 5, representing the best compromise between the lactonization step and the amino-carbonyl reaction. Significant amounts of sotolone were generated only at temperatures higher than 70 °C. The yield increased over a period of 10 h to about 210 μg/mg 1 (23.8 mol %). The Strecker degradation of 1, resulting in 3-hydroxy-2-methylbutanal, was a competitive reaction to the formation of sotolone.
- Blank, Imre,Lin, Jianming,Fumeaux, René,Welti, Dieter H.,Fay, Laurent B.
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p. 1851 - 1856
(2007/10/03)
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- Synthesis of 3-Hydroxy-4,5-dimethyl-2(5H)-furanone and its analogues; utilisation of an intramolecular darzens reaction
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The intramolecular Darzens reaction of chloroacetates of hydroxy ketones leads to α, β-epoxy-γ-and δ-lactones. Acid catalysed rearrangement of the latter furnished the α-keto lactones 1, 10, 16 and 20.
- Frater,Mueller
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p. 2753 - 2756
(2007/10/02)
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