10171-38-7Relevant articles and documents
Secondary α-Deuterium Isotope Effects for the Cleavage of Formaldehyde Hemiacetals through Concerted and Specific-Base-Catalyzed Pathways
Palmer, John L.,Jencks, William P.
, p. 6472 - 6481 (1980)
The observed secondary α-deuterium isotope effects for catalysis by acetate ion of the cleavage of formaldehyde hemiacetals increase from k2H/k2D = 1.23 to 1.28 to 1.34 with decreasing pK of the leaving alcohol in the series ethanol, chloroethanol, and trifluoroethanol.The pH-independent reaction shows a smaller isotope effect of 1.15-1.14 for the ethyl and chloroethyl hemiacetals.These reactions involve general-base catalysis of alcohol attack in the addition direction and the kinetically equivalent cleavage of the hemiacetal anion with general-acid catalysis by acetic acid or the proton in the cleavage direction.The results indicate that the amount of C-O cleavage in the transition state increases with decreasing pK of the alcohol and increasing pK of the acid catalyst, corresponding to a negative coefficient pyy'=δρn/-δpK1g = δβ1g/-δ? and a positive coefficient pxy = δρn/-δpKHA = δα/δ?.These results provide additional support for a concerted reaction mechanism with an important role of proton transfer in the transition state.Qualitative and semiquantitative characterizations of the transition state are presented in terms of reaction coordinate diagrams that are defined by the structure-reactivity parameters.The properties of the transition state suggest that the reaction is best regarded as an electrophilic displacement on the oxygen atom by the proton and by the carbonyl group in the cleavage and addition directions, respectively.The large secondary isotope effect of k2H/k2D = 1.63 for cleavage of the chloroethyl and trifluoroethyl hemiacetals catalyzed by hydroxide ion indicates a late transition state for alkoxide expulsion from the hemiacetal anion.
Simple organocatalysts in multi-step reactions: An efficient one-pot Morita-Baylis-Hillman-type α-hydroxymethylation of vinyl ketones followed by the convenient, temperature-controlled one-pot etherification using alcohols
Mantel, Marvin,Guder, Marian,Pietruszka, J?rg
, p. 5442 - 5450 (2018)
1,4-Diazabicyclo[2.2.2]octane (DABCO) was utilized as versatile catalyst in a one-pot synthesis: First, for the preparation of alcoholic formaldehyde solutions from para-formaldehyde catalysed by using low loadings of inexpensive DABCO. Second, for the fast α-hydroxymethylation of alkylic and aromatic vinyl ketones in high yields. In a third step, the same catalyst can be used for an optional, temperature controlled in situ etherification of the Morita-Baylis-Hillman product with various alcohols on a multi-gram scale in moderate to good overall yields and high purities. Furthermore, an application of the ether in the enantioselective synthesis of a common building block for total synthesis is shown, thus providing a gram-scale access from inexpensive bulk chemicals.
Ruthenium-Catalyzed Synthesis of Dialkoxymethane Ethers Utilizing Carbon Dioxide and Molecular Hydrogen
Thenert, Katharina,Beydoun, Kassem,Wiesenthal, Jan,Leitner, Walter,Klankermayer, Jürgen
, p. 12266 - 12269 (2016)
The synthesis of dimethoxymethane (DMM) by a multistep reaction of methanol with carbon dioxide and molecular hydrogen is reported. Using the molecular catalyst [Ru(triphos)(tmm)] in combination with the Lewis acid Al(OTf)3resulted in a versatile catalytic system for the synthesis of various dialkoxymethane ethers. This new catalytic reaction provides the first synthetic example for the selective conversion of carbon dioxide and hydrogen into a formaldehyde oxidation level, thus opening access to new molecular structures using this important C1source.
Reaction Mechanism from Structure-Energy Relations. 1. Base-Catalyzed Addition of Alcohols to Formaldehyde
Grunwald, Ernest
, p. 4710 - 4715 (1985)
There is a long-standing evidence that in the general base catalyzed addition of alcohols to formaldehyde, C...O bond formation and proton transfer occur simultaneously.Structure-energy relations for this reaction are complicated.The slopes of Bronsted plots vary greatly, even for structurally similar alcohols, and plots of log k vs. pKa of the alcohols go through minima.The data thus provide good material for testing the author's recent theory of structure-energy relations for concerted reactions.The theoretical equations are nonlinear and depend specifically on the reaction mechanism.Of four mechanisms, only that favored by previous independent work fits the data well, even onto reproducing the rate-constant minima.The rate-determining step of this mechanism is R'CH2COO(-) + RCH2OH + H2C=O -> R'CH2COOH + RCH2OCH2O(-).R ranges in electronegativity from CH3 to CF3, R' from H to CN.Assuming this mechanism to be correct, progress of C...O bond formation (u) and proton transfer (v) were deduced from the theoretical equations.The results show that mean progress at the transition state, (u + v)/2, varies only sightly with substitution, but that disparity of progress of the two reaction events, (v-u)/2, varies markedly both with R and R' and changes sign within the series.Rate-constant minima occur near points where u = v, thus proving the effectiveness of disparity at lowering the free energy of activation.
SIDEROPHORE CONJUGATED PYRAZOLIDINONES, AND ANALOGUES THEREOF
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Page/Page column 23, (2020/02/14)
In one aspect, the invention provides compounds and methods that are useful for treating bacterial infections.
Effect of aliphatic alcohols on the reaction of acetoacetic ester with formaldehyde and primary amines
Ishmiyarov,Latypova,Spirikhin,Galkin,Kuleshov,Dokichev
, p. 837 - 840 (2015/06/08)
Abstract Composition of hemiacetals formed by the reaction of paraformaldehyde with aliphatic alcohols in the presence of catalytic amounts of Et3N was studied and the effect of the nature of hemiacetals on the yield and composition of the products of their condensation with acetoacetic ester and primary amines under the Mannich reaction conditions was examined.
Supercritical fluid phase synthesis of methylene lactones using oxynitride catlayst
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Page/Page column 6, (2008/06/13)
Process for converting certain lactones to their alpha-methylene substituted forms in a supercritical or near-critical fluid phase reaction using an oxynitride catalyst or a composite oxynitride catalyst incorporating lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, or barium or combinations thereof.
Supercritical fluid phase synthesis of methylene lactones using novel catalyst field of invention
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Page/Page column 7, (2008/06/13)
Process for converting certain lactones to their alpha-methylene substituted forms that not only exhibits high initial activity (conversion), but also provides high reactor productivity (mass of product per mass of catalyst per unit of time) and sustained maintenance of a high level of activity and productivity with time on stream.
Supercritical fluid phase synthesis of methylene lactones using novel grafted catalyst
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Page/Page column 7, (2010/02/15)
Process for converting certain lactones to their alpha-methylene substituted forms in a supercritical or near-critical fluid phase reaction using a novel grafted catalyst that not only exhibits high initial activity (conversion), but also maintains a high level of activity with time on stream.
Process for the production of y-methyl-a-methylene-y-butyrolactone from reaction of levulinic acid and hydrogen with recycle of unreacted levulinic acid followed by reaction of crude y-valerolactone and formaldehyde, both reactions being carried out in the supercritical or near-critical fluid phase
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Page/Page column 4; 5, (2008/06/13)
Process for the production of γ-methyl-α-methylene-γ-butyrolactone from reaction of levulinic acid and hydrogen with recycle of unreacted levulinic acid and reaction of crude γ-valerolactone and formaldehyde, both reactions being carried out in the supercritical or near-critical fluid phase.
