- Synthesis of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one from maltol and its taste identification
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2,3-Dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) exists in many foods, and its effect on taste is controversial. The aim of this study was to clarify whether DDMP has bitter taste or not. For this purpose, DDMP was synthesized from maltol instead of from glucose for the first time. In contrast, DDMP derived from glucose was also prepared and further purified. Their structures were identified by NMR and MS, and considered to be the same substance. The sensory analysis showed that DDMP derived from maltol was tasteless. Further studies indicated that some impurities in Maillard reaction made DDMP derived from glucose taste bitter.
- Chen, Zhifei,Xi, Gaolei,Fu, Yufeng,Wang, Qingfu,Cai, Lili,Zhao, Zhiwei,Liu, Qiang,Bai, Bing,Ma, Yuping
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- Synthesis method of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one
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The invention relates to a synthesis method of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, which creatively uses maltose as an initial raw material to synthesize the 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one. The synthesis method comprises: firstly, generating maltol acetate through acetylation; secondly, carrying out catalytic hydrogenation to obtain dihydromaltol acetate; adding asilylation reagent again to synthesize a dihydromaltol acetate silyl enol ether compound; increasing reaction activity of 5-position methylene and introducing hydroxy to the 5-position through peroxidation to obtain 5-hydroxy-dihydromaltol acetate; and performing a deacetylation reaction to obtain the 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one that is a target compound. According to the technical scheme, the five-step reaction process is simple, the yield is higher than 80%, the purity of the final product reaches 98% or above, large-scale production can be conducted, and the method has a wide application prospect.
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Paragraph 0039-0040; 0045-0046; 0051-0052; 0057-0058
(2020/02/14)
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- Preparation method of 3-(benzyloxy)-4-oxo-4H-pyran-2-carboxylic acid
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The invention relates to a novel synthesis route of 3-(benzyloxy)-4-oxo-4H-pyran-2-carboxylic acid. 3-hydroxy-2-methyl-4H-pyran-4-one used as a raw material undergoes acetyl protection, a brominationreaction, benzyl protection and oxidation reaction to synthesize a dolutegravir intermediate in four steps at a high yield. The above preparation method of 3-(benzyloxy)-4-oxo-4H-pyran-2-carboxylic acid has the advantages of high yield, low cost, environmental protection, easiness operation, and suitableness for realizing industrialization.
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Paragraph 0031-0033
(2019/10/01)
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- Antioxidant Properties of Heterocyclic Intermediates of the Maillard Reaction and Structurally Related Compounds
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It is well established that a wide range of reductones is formed in the course of the Maillard reaction and that these substances contribute to the oxidative stability of food. The aim of this study was to analyze 12 important heterocyclic intermediates with and without reductone structure as well as structurally related substances under equal conditions to compare their antioxidant properties in detail. For this purpose, five methods were selected including photometrical methods such as the trolox equivalent antioxidant capacity assay and an electron paramagnetic resonance spectroscopic method. Reductones with furan-3-one structure and 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one were reducing in all assays, whereas isomaltol and maltol did not react in assays based on the reduction of metal ions because of their complexing abilities. The introduction of protecting groups to the free hydroxyl functions of selected reductones could nearly eliminate their reducing abilities. In addition, the oxidation products of the different reductive heterocycles were compared after treatment with iodine. Mainly short-chained organic acids such as lactic, glycolic, and glyceric acid are formed as result of the degradation, which indicates 1,3-dicarbonyl cleavage reactions of corresponding tricarbonyl compounds as intermediates of the oxidation.
- Kanzler, Clemens,Haase, Paul T.,Schestkowa, Helena,Kroh, Lothar W.
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p. 7829 - 7837
(2016/10/31)
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- Evaluating prodrug strategies for esterase-triggered release of alcohols
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Prodrugs are effective tools in overcoming drawbacks typically associated with drug formulation and delivery. Those employing esterase-triggered functional groups are frequently utilized to mask polar carboxylic acids and phenols, increasing drug-like properties such as lipophilicity. Herein we detail a comprehensive assessment for strategies that effectively release hydroxy and phenolic moieties in the presence of an esterase. Matrix metalloproteinases (MMPs) serve as our proof-of-concept target. Three distinct ester-responsive protecting groups are incorporated into MMP proinhibitors containing hydroxy moieties. Analytical evaluation of the proinhibitors demonstrates that the use of a benzyl ether group appended to the esterase trigger leads to considerably faster kinetics of conversion and enhanced aqueous stability when compared with more conventional approaches where the trigger is directly attached to the inhibitor. Biological assays confirm that all protecting groups effectively cleave in the presence of esterase to generate the active inhibitor. The superior reaction-based prodrug strategies presented here should serve as a platform for esterase-responsive prodrug design in the future.
- Perez, Christian,Daniel, Kevin B.,Cohen, Seth M.
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supporting information
p. 1662 - 1667
(2013/10/21)
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- A New Microwave Reactor for Batchwise Organic Synthesis
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A laboratory-scale microwave batch reactor (MBR) has been developed for organic synthesis or kinetic studies on the 20-100 mL scale, with upper operating limits of 260 deg C and 10 MPa (100 atm).The MBR complements a continuous microwave reactor which was the subject of a previous report from the author's laboratory.Microwave-assisted organic reactions were conducted safely and conveniently in the MBR, for lengthy periods when required, and in volatile organic solvents.The use of water as a solvent for organic reactions was also explored.Examples include oxidation, elimination, esterifications, hydrolysis of a tertiary amide, etherification, isomerization, Hofmann elimination, α-iodination of a carboxylic acid, Claisen rearrangement, aminoreductone formation, and Willgerodt reactions.Advantages of the new MBR include the capability for rapid heating and quenching of reaction mixtures, minimal temperature gradients within the sample, and elimination of wall effects.Safety aspects have been discussed.
- Raner, Kevin D.,Strauss, Christopher R.,Trainor, Robert W.,Thorn, John S.
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p. 2456 - 2460
(2007/10/02)
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- Synthesis and antiplatelet effects of the new antithrombotic agent aspalatone with low ulcerogenicity
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A new compound, aspalatone (acetylsalicylic acid maltol ester), was synthesized by esterification of acetylsalicylic acid (ASA) and maltol, an antioxidant, and studied for its bleeding time prolongation effect in rats for its antiplatelet aggregation activity in vitro and ex vitro in rats, and for its antithrombotic activity in vivo using the mouse thromboembolism test. Aspalatone treatment (15 mg/kg p.o.) for 10 days prolonged bleeding time by 57% (p 50 of 1.8 x 10-4 mol/l, but, similar to ASA, did not significantly inhibit ADP-induced aggregation. The ability of oral aspalatone to inhibit platelet aggregation in rats ex vivo was compared with other reference antiplatelet drugs. Relative potency was ASA > dipyridamole ? aspalatone > ticlopidine. A single dose of asplatone potently prevented death due to collagen-induced platelet aggregation in mice in vivo with ED50 value of 32 mg/kg p.o., but failed to prevent death due to ADP-induced platelet aggregation. When given for 10 days, aspalatone prevented collagen-induced death by 90% (p 50 values for malondialdehyde degeneration in vitro were 1.1 x 10-4 mol/l and 8.4 x 10-5 mol/l, respectively. These results suggest that aspalatone might be a potential antithrombotic agent with low ulcerogenicity.
- Han,Suh,Yang,Park,Kang,Kim
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p. 1122 - 1126
(2007/10/02)
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