- A new class of high-performance thermoset resins using dicyanoimidazole (DCI) as crosslinking group: A key demo of synthesis, curing behavior and thermal properties
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A novel full-aromatic dicyanoimidazole (DCI) resin monomer—2,2'-((1,4-phenylenebis(oxy))bis(4,1-phenylene))bis(1H-imidazole-4,5-dicarbonitrile) (4PODCI)was synthesized by a simple Schiff base route. A variety of research methods (including FT-IR, UV–Vis, molecular simulation, model monomer, etc.) were applied to study the curing behavior of 4PODCI, the results show that the curing reaction of 4PODCI can be accelerated by N–H on the imidazole, and triazine is observed in the cured products. The 5% weight loss (T5%) of cured 4PODCI under nitrogen and air atmosphere is as high as 591 °C and 558.5 °C respectively, and its Tg is above 500 °C. These results confirm the excellent thermal and thermomechanical properties of cured 4PODCI, and DCI can be employed as a new type of cross-linked elements of high-performance thermosetting resin.
- He, Xian,Hong, Jinlang,Hu, Jianghuai,Liao, Shenjun,Lv, Jiangbo,Tan, Wei,Yang, Gang,Zeng, Ke,Zhu, Zhengzhu
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- Oxidative and Reductive Cross-Coupling Reactions Catalyzed by an Anionic "ligandless" Palladium Complex
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The anionic complex [NBu4][Pd(DMSO)Cl3], which can be synthesized on a gram scale in a single step starting from commercially available starting materials, has been shown to be an active catalyst in the Mizoroki-Heck reaction of aryl halides. We present two new catalytic applications of this complex: the base-free oxidative Heck reaction and the reductive homodimerization of aryl halides. This complex outperformed other palladium salts. In the latter reaction, the catalyst loading could be reduced to 0.01 mol %. The scope of the reactions has been explored, demonstrating the potential of the anionic palladium complex in these catalytic transformations.
- Schroeter, Felix,Lerch, Swantje,Strassner, Thomas
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supporting information
p. 1614 - 1621
(2019/01/04)
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- Synthesis, characterization and catalytic activity of novel large network polystyrene-immobilized organic bases
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In view of searching for efficient polymeric supports for organic bases to be used in environmentally friendly reaction conditions, novel gel-type cross-linked polystyrenes functionalized with diethylamine and 1,5,7-triazabicyclo[4.4.0]dec-5-ene, have been prepared. The structural properties and morphology of these catalysts have been determined by extensive solid state NMR experiments, FTIR spectroscopy and SEM/TEM microscopy. SPACeR-supported bases were found to exhibit high catalytic activity in the epoxide ring opening by phenols. A range of β-substituted alcohols have been readily and regioselectively synthesized.
- Tassi, Marco,Bartollini, Elena,Adriaensens, Peter,Bianchi, Luca,Barkakaty, Balaka,Carleer, Robert,Chen, Jihua,Hensley, Dale K.,Marrocchi, Assunta,Vaccaro, Luigi
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p. 107200 - 107208
(2016/01/08)
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- (Aryloxy)aryl semicarbazones and related compounds: A novel class of anticonvulsant agents possessing high activity in the maximal electroshock screen
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A number of (aryloxy)aryl semicarbazones and related compounds were synthesized and evaluated far anticonvulsant activities. After intraperitoneal injection to mice, the semicarbazones were examined in the maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ), and neurotoxicity (NT) screens. The results indicated that greater protection was obtained in the MES test than the scPTZ screen. Quantitation of approximately one-third of the compounds revealed an average protection index (PI, i.e. TD50/ED50) of approximately 9. After oral administration to rats, a number of compounds displayed significant potencies in the MES screen (ED50 of 1-5 mg/kg) accompanied by very high protection indices. In fact over half the compounds had PI figures of greater than 100, and two were in excess of 300. The compounds were essentially inactive in the scPTZ and NT screens after oral administration to rats. Various compounds displayed greater potencies and PI figures in the mouse intraperitoneal and rat oral screens than three reference clinically used drugs. The data generated supported a binding site hypothesis. Quantitative structure-activity relationships indicated a number of physicochemical parameters which contributed to activity in the MES screen. X-ray crystallography of five compounds suggested the importance of certain interatomic distances and bond angles for activity in the mouse and rat MES screens.
- Dimmock, Jonathan R.,Puthucode, Ramanan N.,Smith, Jennifer M.,Hetherington, Mark,Quail, J. Wilson,Pugazhenthi, Uma,Lechler, Terry,Stables, James P.
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p. 3984 - 3997
(2007/10/03)
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- A convenient method for the preparation of 4-aryloxyphenols
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A convenient method for the preparation of 4-aryloxyphenols via the homologation of preformed phenols is described. Condensation of various 4-substituted phenols with either 4-fluorobenzaldehyde (8) or 4-fluoroacetophenone (9) yielded the corresponding 4-aryl-oxybenzaldehydes, 10, and acetophenones, 11, in 70-93% yield. Baeyer-Villiger oxidation of these materials with 3-chloroperoxybenzoic acid (MCPBA) yielded the corresponding 4-formyloxy and 4-acetoxyphenyl ethers which were hydrolyzed without purification to the desired 4-aryloxyphenols 12 in 72-94% yield. Both 4-fluorobenzaldehyde (8) and 4-fluoroacetophenone (9) are synthetically equivalent to the a4 umpoled synthon 6. Extension of this methodology of the preparation of 4,4'-[arylbis(oxy)]bisphenols from aromatic diols is also described. Condensation of various aromatic diols with 8 or 9 yielded the corresponding 4,4'-[arylbis(oxy)]bisbenzaldehydes 15 and acetophenones 16 in 71-89% yield. Baeyer-Villiger oxidation of these compounds with MCPBA yielded the desired 4,4'-[arylbis(oxy)]bisphenyl bisformates 17 and bisacetates 18 in 67-84% yield. Hydrolysis of these compounds afforded the desired 4,4'-[arylbis(oxy)bisphenols 19 in 70-91% yield.
- Yeager,Schissel
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- Hydroxy-terminated arylene ethers, and method for making
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A method is provided for making certain hydroxy-terminated arylene ethers useful as spacers in liquid crystalline polyesters. There is initially formed a dicarbonyl adduct from a dihydroxyaromatic compound, such as hydroquinone and a haloarylcarbonyl compound. The adduct formed is oxidized to the corresponding diester. Hydrolysis of the diester provides the hydroxy-terminated arylene ether.
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