30934-97-5Relevant academic research and scientific papers
Preparation method of 2, 2-dimethoxyacetaldehyde
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Paragraph 0026; 0027; 0029; 0030; 0032; 0033; 0035; 0036, (2020/07/21)
The invention discloses a preparation method of 1, 2-dimethoxyacetaldehyde. Hydroxyacetaldehyde is adopted as a raw material and a methanol raw material, S2O8 /Zn-MCM-41 solid superacid is adopted as a catalyst, the acidity is high and 2, 2-methoxyethanol can be obtained with high selectivity, then 2, 2-methoxyacetaldehyde is obtained under the action of an oxidizing agent, the product is easy to separate, and the purity of dimethoxyacetaldehyde reaches up to 95% or above.
Catalysis and Stability Effect of Solvent Alcohol on the C6 Aldose Conversion toward Tetrose
Hou, Wenrong,Yan, Yueer,Li, Gang,Zhan, Yulu,Feng, Lei,Zhang, Ruohong,Hua Li, Zhen,Zhang, Yahong,Tang, Yi
, p. 4182 - 4188 (2019/09/12)
Conversions of biomass feedstock into various valuable chemicals are of great significance. As a typical route, retro-aldol condensation of monosaccharide greatly expands the variety of biomass-derived platform chemicals via a selective C?C splitting. Herein, we describe a solvent-catalysed strategy to high-selectively accumulate tetrose (four-carbon platform chemical) from C6 aldoses via the retro-aldol/aldol process. We find that alcohol solvents with Lewis acidity facilitate the C?C splitting process of hexose under the catalyst-free condition. The conversion is the fastest in methanol while it is the slowest in isopropanol. The product distribution is greatly influenced by the alcohols through shifting the equilibrium between tetrose and glycolaldehyde (GA). The addition of catalyst only accelerates the reaction rate, and does not change the product distribution. On the one hand, the acetalization of GA with methanol or ethanol shifts the equilibrium from tetrose toward GA, which results in a low yield of tetrose in methanol or ethanol solvent. On the other hand, tetrose can be well accumulated in isopropanol or n-butanol, and the yield of tetrose in isopropanol is higher than in n-butanol because tetrose can be well solvated and stabilized in it. This solvent-dependent reaction strategy provides a new possibility which contributes to the conversion of biomass feedback into valuable platform chemicals and accumulation of target products by utilizing the solvation effect.
Heterocyclic Compound
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Paragraph 2270; 2271, (2018/06/15)
The present invention provide a compound having an orexin receptor antagonistic activity, which is expected to be useful as medicaments such as agents for the prophylaxis or treatment of sleep disorder, depression, anxiety disorder, panic disorder, schizophrenia, drug dependence, Alzheimer's disease and the like. The present invention relates to a compound represented by the formula (I): wherein each symbol is as defined in the specification, or a salt thereof.
Synthesis of a novel polyester building block from pentoses by tin-containing silicates
Elliot,Andersen,Tolborg,Meier,Sádaba,Daugaard,Taarning
, p. 985 - 996 (2017/01/13)
We report here the direct formation of the new chemical product trans-2,5-dihydroxy-3-pentenoic acid methyl ester from pentoses using tin-containing silicates as catalysts. The product is formed under alkali-free conditions in methanol at temperatures in the range 140-180 °C. The highest yields are found using Sn-Beta as the catalyst. Under optimised conditions, a yield of 33% is achieved. Purified trans-2,5-dihydroxy-3-pentenoic acid methyl ester was used for co-polymerisation studies with ethyl 6-hydroxyhexanoate using Candida antarctica lipase B as the catalyst. The co-polymerisation yields a product containing functional groups originating from trans-2,5-dihydroxy-3-pentenoic acid methyl ester in the polyester backbone. The reactivity of the incorporated olefin and hydroxyl moieties was investigated using trifluoroacetic anhydride and thiol-ene chemistry, thus illustrating the potential for functionalising the new co-polymers.
Mechanistic insights into the production of methyl lactate by catalytic conversion of carbohydrates on mesoporous Zr-SBA-15
Yang, Lisha,Yang, Xiaokun,Tian, Elli,Vattipalli, Vivek,Fan, Wei,Lin, Hongfei
, p. 207 - 216 (2015/12/04)
The as-synthesized Zr-SBA-15 catalysts with tunable mesoporous structures showed excellent catalytic performance for the conversion of carbohydrates to methyl lactate in a "one-pot" process using near-critical methanol or methanol-water mixture as the solvents. The effects of reaction conditions, including temperature, reaction time, and catalyst loading amount, on the conversions of carbohydrates and the yields of methyl lactate were investigated. The high yields of methyl lactate, up to 41% and 44%, were produced from pentose and hexose, respectively, in the near-critical methanol at 240 °C. Moreover, the Si/Zr ratio of the Zr-SBA-15 catalysts profoundly affected the Lewis acidity and therefore the catalytic activity and selectivity to methyl lactate in the conversion of carbohydrates. The pore size of the Zr-SBA-15 catalysts, tuned by the synthesis temperature, strongly affected the formation of solid residues. The key intermediates such as glyceraldehyde, glycolaldehyde, and pyruvaldehyde were used as probe reactants to understand the mechanism. The role of the Zr-SBA-15 catalyst in the aldol- and retro-aldol condensation, isomerization, and Cannizzaro reactions of carbohydrates and their derivatives was discussed. Furthermore, 28% and 27% yields of methyl lactate were obtained from cellulose and starch, respectively, in methanol-water mixture (5 wt% water and 95 wt% methanol) at 240 °C. The Zr-SBA-15 catalyst was relatively stable in short term without regeneration.
Toward functional polyester building blocks from renewable glycolaldehyde with sn cascade catalysis
Dusselier, Michiel,Van Wouwe, Pieter,De Smet, Sanne,De Clercq, Rik,Verbelen, Leander,Van Puyvelde, Peter,Du Prez, Filip E.,Sels, Bert F.
, p. 1786 - 1800 (2013/09/02)
Having been inspired by formose-based hypotheses surrounding the origin of life, we report on a novel catalytic route toward a series of recently discovered four-carbon α-hydroxy acids (AHA) and their esters from accessible and renewable glycolaldehyde (GA) in various solvents. The synthesis route follows a cascade type reaction network, and its mechanism with identification of the rate-determining step was investigated with in situ 13C NMR. The mechanistic understanding led to optimized reaction conditions with higher overall rates of AHA formation by balancing Bronsted and Lewis acid activity, both originating from the tin halide catalyst. An optimal H+/Sn ratio of 3 was identified, and this number was surprisingly irrespective of the Sn oxidation state. Further rate enhancement was accomplished by adding small amounts of water to the reaction mixture, boosting the rate by a factor of 4.5 compared with pure methanol solvent. The cascade reaction selectively yields near 60% methyl-4-methoxy-2- hydroxybutanoate (MMHB). In the optimized rate regime in methanol, an initial TOF of 7.4 molGA molSn-1 h-1 was found. In sterically hindered alcohols (isopropyl alcohol), the rate of AHA formation was even higher, and the corresponding vinyl glycolate esters arose as the main product. Vinyl glycolic acid, 2,4-dihydroxybutanoic acid, and its lactone were formed significantly in nonprotic solvent. The corresponding AHAs have serious potential as building blocks in novel biobased polymers with tunable functionality. The incorporation of vinyl glycolic acid in polylactic acid-based polyesters is illustrated, and postmodification at the vinyl side groups indeed allows access to a range of properties, such as tunable hydrophilicity, which is otherwise difficult to attain for pure poly(l-lactic acid).
Sn-Beta catalysed conversion of hemicellulosic sugars
Holm, Martin S.,Pagan-Torres, Yomaira J.,Saravanamurugan, Shunmugavel,Riisager, Anders,Dumesic, James A.,Taarning, Esben
experimental part, p. 702 - 706 (2012/04/23)
Conversions of various pentoses and hexoses into methyl lactate has been demonstrated for the Sn-Beta catalyst. It is found that pentoses are converted to methyl lactate in slightly lower yields (～40%) than what is obtained for hexoses (～50%), but higher yields of glycolaldehyde dimethyl acetal are observed for the pentoses. This finding is in accordance to a reaction pathway that involves the retro aldol condensation of the sugars to form a triose and glycolaldehyde for the pentoses, and two trioses for hexoses. When reacting glycolaldehyde (formally a C2-sugar) in the presence of Sn-Beta, aldol condensation occurs, leading to the formation of methyl lactate, methyl vinylglycolate and methyl 2-hydroxy-4-methoxybutanoate. In contrast, when converting the sugars in water at low temperatures (100 °C), Sn-Beta catalyses the isomerisation of sugars (ketose-aldose epimers), rather than the formation of lactates. The Royal Society of Chemistry 2012.
A COMBINED FORMOSE/TRANSFER HYDROGENATION PROCESS FOR ETHYLENE GLYCOL SYNTHESIS
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Page/Page column 19-20, (2009/05/28)
The present invention provides a process for the production of a glycol via tandem self condensation of formaldehyde via formoin condensation and transfer hydrogenation of the reaction products of the formoin condensation. In some aspects, synthetic processes of the present invention utilize a combination of a N-heterocyclic carbene catalyst and a transition metal hydrogen-transfer catalyst providing enhanced selectivity and increased yields for the production of ethylene glycol relative to conventional synthetic approaches based on formoin condensation.
A New Iterative Route to Optically Active Polyols Using α-Alkoxy Silanes as Key Intermediates
Yoshida, Jun-ichi,Maekawa, Tsuyoshi,Morita, Yuko,Isoe, Sachihiko
, p. 1321 - 1322 (2007/10/02)
A new iterative and modular strategy which is applicable to the synthesis of any enantiomers and diastereomers of straight chain 1,n-polyols has been developed utilizing electrochemical oxidation of α-alkoxy silanes.
The highly syn-selective Michael reaction of enamines with 2-(1-alkenyl)-1,3-dioxolan-2-ylium cations generated from 2,2-dimethoxyethyl 2-alkenoates in situ
Machida,Hashimoto,Saigo,Inoue,Hasegawa
, p. 3737 - 3752 (2007/12/18)
2,2-Dimethoxyethyl 2-alkenoates are easily transformed into 2-(1-alkenyl)-1,3-dioxolan-2-ylium cations in situ on the action of titanium tetrachloride, which react with enamines to predominantly give syn Michael adducts in good yields. This is the first example of such a high syn-selectivity for the Michael reaction of α,β-unsaturated ester derivatives with ketone enolate equivalents.
