609-08-5Relevant articles and documents
Synthesis, Electronic Spectroscopy, and Photochemistry of Methacrolein Oxide: A Four-Carbon Unsaturated Criegee Intermediate from Isoprene Ozonolysis
Vansco, Michael F.,Marchetti, Barbara,Trongsiriwat, Nisalak,Bhagde, Trisha,Wang, Guanghan,Walsh, Patrick J.,Klippenstein, Stephen J.,Lester, Marsha I.
, p. 15058 - 15069 (2019)
Ozonolysis of isoprene, one of the most abundant volatile organic compounds in the earth's atmosphere, generates the four-carbon unsaturated methacrolein oxide (MACR-oxide) Criegee intermediate. The first laboratory synthesis and direct detection of MACR-oxide is achieved through reaction of photolytically generated, resonance-stabilized iodoalkene radicals with oxygen. MACR-oxide is characterized on its first π? a? πelectronic transition using a ground-state depletion method. MACR-oxide exhibits a broad UV-visible spectrum peaked at 380 nm with weak oscillatory structure at long wavelengths ascribed to vibrational resonances. Complementary theory predicts two strong ?€? a? πtransitions arising from extended conjugation across MACR-oxide with overlapping contributions from its four conformers. Electronic promotion to the 11π? state agrees well with experiment, and results in nonadiabatic coupling and prompt release of O 1D products observed as anisotropic velocity-map images. This UV-visible detection scheme will enable study of its unimolecular and bimolecular reactions under thermal conditions of relevance to the atmosphere.
Dynamic Kinetic Resolution of I-Substituted Cyclic β-Ketoesters via Asymmetric Hydrogenation: Constructing Chiral Cyclic β-Hydroxyesters with Three Contiguous Stereocenters
Yang, Dan,Wu, Xiong,Zheng, Xiao-Jie,Xie, Jian-Hua,Zhou, Qi-Lin
supporting information, p. 5153 - 5157 (2021/07/20)
An efficient asymmetric hydrogenation of racemic I-substituted cyclic β-ketoesters via dynamic kinetic resolution to provide chiral cyclic β-hydroxy esters with three contiguous stereocenters is reported. Using a chiral spiro iridium catalyst (R)-5 (Ir-SpiroSAP), a series of racemic I-Aryl/alkyl substituted cyclic β-ketoesters were hydrogenated to the corresponding chiral cyclic β-hydroxy esters in high yields (84-97%) with good to excellent enantioselectivities (69->99% ee) and cis,cis-selectivities (up to >99:1).
Preparation of mono-substituted malonic acid half oxyesters (SMAHOs)
Condon, Sylvie,Le Gall, Erwan,Pichon, Christophe,Presset, Marc,Xavier, Tania
supporting information, p. 2085 - 2094 (2021/09/02)
The use of mono-substituted malonic acid half oxyesters (SMAHOs) has been hampered by the sporadic references describing their preparation. An evaluation of different approaches has been achieved, allowing to define the best strategies to introduce diversity on both the malonic position and the ester function. A classical alkylation step of a malonate by an alkyl halide followed by a monosaponification gave access to reagents bearing different substituents at the malonic position, including functionalized derivatives. On the other hand, the development of a monoesterification step of a substituted malonic acid derivative proved to be the best entry for diversity at the ester function, rather than the use of an intermediate Meldrum acid. Both these transformations are characterized by their simplicity and efficiency, allowing a straightforward access to SMAHOs from cheap starting materials.
Acetal Addition to Electron-Deficient Alkenes with Hydrogen Atom Transfer as a Radical Chain Propagation Step
Chan, Wei Chuen,Vinod, Jincy K.,Koide, Kazunori
, p. 3674 - 3682 (2021/02/16)
We describe a visible-light-promoted addition of a hydrogen atom and an acetal carbon toward various electron-deficient alkenes. 1,3-Dioxolane is converted to its radical species in the presence of persulfate and an iridium catalyst upon visible light irradiation, which then reacts with electron-deficient alkenes. The reaction operates via a radical chain mechanism, a less commonly observed pathway for this class of transformation. Hydrogen atom transfer from 1,3-dioxolane to α-malonyl radicals is corroborated by experimental and density functional theory studies.
Apple flavor compound, preparation method thereof and food additive
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Paragraph 0064-0066; 0081; 0082; 0086; 0090; 0091, (2020/07/13)
The invention relates to an apple flavor compound, a preparation method thereof and a food additive. The apple flavor compound has a structural formula shown as the specification, the apple flavor compound can be named as 1-(1-(1-(3, 3-dimethylcyclohexyl)ethyl)3-ethyl malonic acid malonate. Experiments prove that the compound has obvious mature sweet apple fragrance, can be used in food additiveswith apple fragrance, and provides a new source for the apple flavor compound.
Enantioselective α-Amination of Acyclic 1,3-Dicarbonyls Catalyzed by N-Heterocyclic Carbene
Santra, Surojit,Maji, Ujjwal,Guin, Joyram
supporting information, p. 468 - 473 (2020/02/04)
Herein, we describe a method for the catalytic enantioselective α-amination of α-substituted acyclic 1,3-ketoamides and 1,3-amidoesters that affords the products possessing N-substituted quaternary stereocenters with a chiral N-heterocyclic carbene (NHC). The reaction is based on the utilization of an intrinsic Br?nsted base characteristic of NHC that enables the catalytic formation of a chiral ion pair comprising the enolate and the azolium ion. A series of challenging open-chain α-substituted 1,3-dicarbonyls are aminated via this method with ee's of ≤99%.
Preparation method of diethyl methylmalonate by taking heteropolyacid as catalyst
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Paragraph 0013-0020, (2020/05/01)
The invention relates to a preparation method of diethyl methylmalonate by taking heteropolyacid as a catalyst. The method comprises the following steps: adding 2-cyanopropionic acid into ethanol fordissolving, controlling the molar ratio of 2-cyanopropionic acid to ethanol to be 1:(3-4), and transferring the obtained solution into a reaction kettle after dissolving; stirring at room temperature,adding the heteropolyacid catalyst, controlling the mass ratio of 2-cyanopropionic acid to the heteropolyacid catalyst to be 2:(1-2), controlling the temperature to be 65-80 DEG C, reacting for 3-4 h, and then ending the reaction; distilling to separate ethanol, adding ammonia water to neutralize, regulating the pH value to be neutral, and fractionating to obtain crude diethyl methylmalonate; andputting the crude diethyl methylmalonate into a rectifying tower, and carrying out reduced pressure rectification to obtain diethyl methylmalonate. Sulfuric acid is replaced with the heteropolyacid catalyst for an esterification reaction, so the method has the advantages of good selectivity, high catalytic activity, high regeneration speed and small corrosion to equipment.
A methyl acid diethyl ester preparation method
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Paragraph 0061-0075, (2019/04/04)
The invention relates to the field of organic synthetic technology, in particular to a methyl acid diethyl ester preparation method. The present invention provides methyl malonic acid diethyl ester preparation method of the cyano acid hydrolysis, simple process flow; ethanol - thionyl chloride system to carry out the esterification can effectively avoid the use of toxic solvents, and can improve the yield of the final product. According to an embodiment of the record, the invention provides a preparation method, the yield of the DEMM ≥ 62.5%, and the purity is ≥ 98%.
Continuous synthesis method of diethyl methylmalonate
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Paragraph 0011; 0012; 0013; 0014; 0015; 0016; 0017; 0018, (2019/01/08)
The invention belongs to the technical field of organic synthesis, and specifically relates to a continuous synthesis method of diethyl methylmalonate. 2-chloropropionic acid is continuously cyanidedto obtain 2-cyanopropionic acid; 2-cyanopropionic acid and ethanol carry out esterification reactions under the action of sulfuric acid to obtain a crude product of diethyl methylmalonate directly inone step; and the finished product is obtained after steps of washing and distillation. The reaction process is simple, and the yields of hydrolysis and esterification are high.
AlCl3 catalyzed coupling of: N-benzylic sulfonamides with 2-substituted cyanoacetates through carbon-nitrogen bond cleavage
Hu, Chen,Hong, Gang,Qian, Xiaofei,Kim, Kwang Rim,Zhu, Xiaoyan,Wang, Limin
supporting information, p. 4984 - 4991 (2017/07/10)
A new cross-coupling reaction of N-benzylic sulfonamides with 2-substituted cyanoacetates for the synthesis of 2-substituted benzylbenzene was reported. In the presence of AlCl3, a broad range of N-benzylic sulfonamides reacted smoothly with 2-substituted cyanoacetates to afford structurally diverse benzylbenzenes in moderate to excellent yields. The conversion could be enlarged to gram-scale efficiently. The practicability of this approach was further manifested in the synthesis of a related bioactive agent with high anti-inflammatory activity.
