635-10-9Relevant academic research and scientific papers
Synthesis of Core-Modified Third-Generation Light-Driven Molecular Motors
Berrocal, José Augusto,Pfeifer, Lukas,Heijnen, Dorus,Feringa, Ben L.
, p. 10670 - 10680 (2020/09/18)
The synthesis and characterization of a series of light-driven third-generation molecular motors featuring various structural modifications at the central aromatic core are presented. We explore a number of substitution patterns, such as 1,2-dimethoxybenzene, naphthyl, 1,2-dichlorobenzene, 1,1′:2′,1″-terphenyl, 4,4″-dimethoxy-1,1':2′,1″-terphenyl, and 1,2-dicarbomethoxybenzene, considered essential for designing future responsive systems. In many cases, the synthetic routes for both synthetic intermediates and motors reported here are modular, allowing for their post-functionalization. The structural modifications introduced in the core of the motors result in improved solubility and a bathochromic shift of the absorption maxima. These features, in combination with a structural design that presents remote functionalization of the stator with respect to the fluorene rotors, make these novel motors particularly promising as light-responsive actuators in covalent and supramolecular materials.
Functionalized and Degradable Polyphthalaldehyde Derivatives
Lutz, J. Patrick,Davydovich, Oleg,Hannigan, Matthew D.,Moore, Jeffrey S.,Zimmerman, Paul M.,McNeil, Anne J.
supporting information, p. 14544 - 14548 (2019/10/02)
Polymers that depolymerize back to monomers can be repeatedly chemically recycled, thereby reducing their environmental impact. Polyphthalaldehyde is a metastable polymer that can rapidly and quantitatively depolymerize due to its low ceiling temperature. However, the effect of substitution on the physical and chemical properties of polyphthalaldehyde derivatives has not been systematically studied. Herein, we investigate the cationic polymerization of seven o-phthalaldehyde derivatives and demonstrate that judicious choice of substituent results in materials with a wide range of ceiling temperatures (-60 to 106 °C) and decomposition temperatures (109-196 °C). We anticipate that these new polymers and their derivatives will enable researchers to access degradable materials with tunable thermal, physical, and chemical properties.
Synthesis method for 1,2,4,5-cyclohexanetetracarboxylic dianhydride
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Paragraph 0036; 0037; 0038; 0062, (2018/06/04)
The invention provides a preparation method for 1,2,4,5-cyclohexanetetracarboxylic dianhydride. The method comprises the following steps: preparing pyromellitic acid ester by reacting pyromellitic acid with an esterification reagent; synthesizing hydrogenated pyromellitic acid ester by adding the pyromellitic acid ester with hydrogen in a fixed bed reactor; obtaining the 1,2,4,5-cyclohexanetetracarboxylic dianhydride by synthesizing the hydrogenated pyromellitic acid ester in strong acids and organic solvents. Compared with a traditional production process, the esterification reaction of the invention has high efficiency, the service life of a catalyst is prolonged, continuous production of hydrogenation reaction is realized, and a process route is shortened. The method has the advantagesof simple operation, high production efficiency and low cost and the like. The content of metal ions (sodium, potassium, iron, calcium, aluminum, and zinc) of the obtained 1,2,4,5-cyclohexanetetracarboxylic dianhydride contains is equal to or less than 1 ppm, and meets requirements of electronic grade products.
Derivative of pyromellitic acid and preparation method of derivative
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Paragraph 0030; 0031, (2017/08/30)
The invention discloses a derivative of pyromellitic acid. The structural formula (I) of the derivative is shown in the specification. A preparation method of the derivative of pyromellitic acid comprises the steps as follows: (1) pyromellitic acid dianhydride and methanol are used as initial materials and subjected to a complete esterification reaction under the action of a catalyst to produce an esterification product; (2) the esterification product and amino alcohol react to produce an aminolysis product; (3) the aminolysis product and sulfoxide chloride react to produce the derivative (I) of pyromellitic acid under the action of NaCO3. The prepared derivative of pyromellitic can be used as a curing agent of an outdoor polyester powder coating, produced films have no pinholes and other defects on surfaces, and the derivative has excellent weather resistance.
Highly chemoselective palladium-catalyzed cross-trimerization between alkyne and alkenes leading to 1,3,5-trienes or 1,2,4,5-tetrasubstituted benzenes with dioxygen
Zhou, Peng,Huang, Liangbin,Jiang, Huanfeng,Wang, Azhong,Li, Xianwei
experimental part, p. 8279 - 8282 (2011/02/23)
A palladium-catalyzed 1:2 linear/cyclic cross-trimerization of alkyne with alkenes using molecular oxygen as the sole oxidant has been reported for the first time. A series of 1,3,5-trienes and 1,2,4,5-tetrasubstituted benzenes are obtained with high chemoselectivity respectively and mechanisms of these reactions are proposed based on some controlled examination.
Esters of pyromellitic acid. Part I. Esters of achiral alcohols: Regioselective synthesis of partial and mixed pyromellitate esters, mechanism of transesterification in the quantitative esterification of the pyromellitate system using orthoformate esters, and a facile synthesis of the ortho pyromellitate diester substitution pattern
Paine III, John B.
, p. 4929 - 4939 (2008/12/21)
(Chemical Equation Presented) Mild conditions and reversible anhydride formation allow a relative differentiation to be made of the four equivalent carbonyl groups of pyromellitic dianhydride (PMDA, benzene-1,2,4,5- tetracarboxylic dianhydride) in esterification, leading to regioselective methods to generate a wide range of partially or totally esterified products or products bearing differing esterifying groups at the different positions. Pyromellitate monoester anhydrides form efficiently in dichloromethane/ triethylamine from 1 equiv of the alcohol. Under the same conditions, two different alcohols can be made to react sequentially. With 2 equiv of an alcohol, the usual mixture of meta and para diesters is obtained, separated by crystallization from HOAc. Meta and para dibenzyl pyromellitates served as regiospecific sources of other diesters, by further esterification followed by hydrogenolysis. Refluxing orthoformate triesters were found to effect quantitative esterification of the pyromellitate system under autocatalytic conditions; minor ester exchange with pre-existing esters (0-5% of total product) was ascribed to reversible anhydride formation. For general esterification with alcohols, partial ester acid chlorides were obtained using oxalyl chloride. Pyromellitate triesters afforded the ortho diester anhydrides upon distillation, thereby providing facile entry into the mostly novel ortho substitution pattern in this system. The requisite triesters were prepared by selective saponification or by the prior incorporation of one benzyl ester substituent, which could be removed by catalytic hydrogenolysis. The various benzyl esters of pyromellitates hydrogenolyzed smoothly to release the carboxylic acid groups without disturbance of pyromellitate aromaticity.
Crystal structure of 1,1′-biphenyl-2,2′,3,3′- tetracarboxylic and 1,1′-biphenyl-2,2′,3,3′,5,5′,6, 6′-octacarboxylic acids: Solid-state chiralization and dissociation
Holy, Petr,Sehnal, Petr,Tichy, Milos,Zavada, Jiri,Cisarova, Ivana
, p. 3805 - 3810 (2007/10/03)
X-ray diffraction analysis revealed unexpected stereochemical features accompanying crystal self-assembly of the two title oligocarboxylic acids.
Cis,cis,cis-1,2,4,5-cyclohexanetetracarboxylic acid and its dianhydride
Uchida, Akira,Hasegawa, Masatoshi,Manami, Hiroshi
, p. o435-o438 (2007/10/03)
Cis,cis,cis-l,2,4,5-CyclohexanetetracarboxyIic acid, C10H 12O8, (I), contains a mirror plane and the cyclohexane ring exhibits a chair conformation. Two crystallographically independent hydrogen bonds form R22(14), R22(16) and R44(16) ring motifs, and propagation of these two hydrogen bonds along the c and b axes generates C22(16) and C22(7) chains. cis,cis,cis-l,2:4,5-Cyclohexanetetracarboxylic dianhydride, C10H 8O6, (II), was prepared by the reaction of (I) with acetic anhydride. The cyclohexane ring of (II) exhibits a boat conformation and the dihedral angle between the two anhydro rings is 117.5 (1)°.
The synthesis of imidazole analogs of the kainoid family
Baumgartner, Hansruedi,O'Sullivan, Anthony C.
, p. 2775 - 2784 (2007/10/03)
In an effort to mimic the anthelmintic and insecticidal activities of kainic 1 and domoic 2 acids with compounds of simpler structure and much easier accessibility, the highly functionalised imidazoIines 4, 27, and 28 were prepared. This involved a synthesis of suitably protected β-aminoglutamic acid derivatives as key intermediates, which were condensed with orthoesters and deprotected to yield the desired compounds.
