共查询到13条相似文献,搜索用时 0 毫秒
1.
Chenyi Yi Ruimao Hua Hanxiang Zeng Qiufeng Huang 《Advanced Synthesis \u0026amp; Catalysis》2007,349(10):1738-1742
An efficient and practical synthetic method has been developed for the preparation of symmetrical diarylacetylenes from the direct reaction of aryl chlorides with 2‐methyl‐3‐butyn‐2‐ol catalyzed by palladium(II) chloride‐bis(tricyclohexylphosphine) [PdCl2(PCy3)2] under mild reaction conditions. Unsymmetrical diarylated acetylenes could be also obtained by using two different aryl chlorides simultaneously. The catalytic procedure includes a novel one‐pot palladium‐catalyzed, double Sonogashira coupling of inactivated aryl chlorides without use of copper(I) as co‐catalyst. 相似文献
2.
Hyman H Rehan 《Polymer International》2003,52(2):218-224
Cyclic voltammetry was used to electropolymerize 2‐phenylazo‐1‐naphthol in 0.2 M NaOH in 30% ethanol/water and in acetonitrile (MeCN). Very thin electro‐inactive polymer films were obtained in alcoholic NaOH while the films formed in MeCN were much thicker and electro‐active in acid solutions. Based on IR and electrochemical behaviour, poly (2‐phenylazo‐1‐naphthol) (PPAN) is assumed to consist of two polymeric segments, in ratios that depend on the nature of the polymerization solvent. Head‐to‐tail coupling led to formation of ether linkages and the electro‐inactive segments, while tail‐to‐tail coupling led to formation of aromatic C? C and quinone moieties in the polymer skeleton and the electro‐active segments. The redox processes of the quinone/quinol transformations were studied by cyclic voltammetry and chronocoulometry. NaOH‐formed films were superior in corrosion protection of steel in 0.5 M sulfuric acid than MeCN‐formed films. PPAN films formed in MeCN were found to mediate the oxidation of ascorbic acid at lower oxidation potential. © 2003 Society of Chemical Industry 相似文献
3.
L Kanwar S Hazarika A Goswami N
N Dutta A
K Hazarika Pranab Goswami 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(8):898-902
Isolation of a novel microbial lipase (EC 3.1.1.3) having specific catalytic activity for the synthesis of optically pure 2‐O‐benzylglycerol‐1‐acetate, the building block for the preparation of many β‐blockers, phospholipase A2 inhibitors and other biologically active compounds was the aim of this investigation. A Pseudomonas (strain G6), recently isolated from soil, produced an extracellular lipase. SDS–PAGE analysis showed that the lipase protein was a hexamer. The molecular weight of the sub‐units of the lipase protein were 10, 19, 29, 30, 47 and 53. The catalytic activity of the lipase was exploited for the synthesis of 2‐O‐benzylglycerol‐1‐acetate from 2‐O‐benzylglycerol through transesterification using vinyl acetate as acylating agent. High selectivity of the lipase towards the monoacetate product was demonstrated. A 97% enantiomeric excess (ee) of S(+)‐2‐O‐benzylglycerol‐1‐acetate was obtained when the reaction was carried out at room temperature with shaking. The lipase was highly active in anhydrous organic microenvironments and in non‐polar organic solvents with log P values above 2.5. © 2002 Society of Chemical Industry 相似文献
4.
Alessandro Palmieri Serena Gabrielli Roberto Ballini 《Advanced Synthesis \u0026amp; Catalysis》2010,352(9):1485-1492
A new class of nitro‐functionalized α,β‐unsaturated esters has been prepared by a regio‐ and diastereoselective Michael addition of nitroalkanes to β‐nitroacrylates, performed at room temperature, under carbonate on polymer as promoter, and in the presence of ethyl acetate as eco‐friendly solvent. Moreover, by the modular choice of the reaction conditions the method allows the synthesis of 1,3‐butadiene‐2‐carboxylates. 相似文献
5.
Krishna Bahadur SomaiMagar Yong Rok Lee 《Advanced Synthesis \u0026amp; Catalysis》2014,356(16):3422-3432
Efficient one‐step syntheses of α,β‐ and β,β‐dihaloenones were achieved by ruthenium(II)‐catalyzed reactions between cyclic or acyclic diazodicarbonyl compounds and oxalyl chloride or oxalyl bromide in moderate to good yields. This methodology offers several significant advantages, which include ease of handling, mild reaction conditions, one‐step reaction, and the use of an effective and non‐toxic catalyst. The synthesized compounds were further transformed into highly functionalized novel molecules bearing aromatic rings on the enone moiety using the Suzuki reaction.
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Isabelle E. François Dr. Karin Thevissen Dr. Klaartje Pellens Dr. Els M. Meert Jan Heeres Dr. Eddy Freyne Dr. Erwin Coesemans Dr. Marcel Viellevoye Dr. Frederik Deroose Dr. Sonia Martinez Gonzalez Dr. Joaquin Pastor Dr. David Corens Dr. Lieven Meerpoel Dr. Marcel Borgers Dr. Jannie Ausma Dr. Gerrit D. Dispersyn Dr. Bruno P. Cammue Prof. Dr. 《ChemMedChem》2009,4(10):1714-1721
In this study, we screened a library of 500 compounds for fungicidal activity via induction of endogenous reactive oxygen species (ROS) accumulation. Structure–activity relationship studies showed that piperazine‐1‐carboxamidine analogues with large atoms or large side chains substituted on the phenyl group at the R3 and R5 positions are characterized by a high ROS accumulation capacity in Candida albicans and a high fungicidal activity. Moreover, we could link the fungicidal mode of action of the piperazine‐1‐carboxamidine derivatives to the accumulation of endogenous ROS. 相似文献
8.
Jie Li Wei Pan Zheng Wang Xumu Zhang Kuiling Ding 《Advanced Synthesis \u0026amp; Catalysis》2012,354(10):1980-1986
The spiro‐2,2′‐bichroman‐based chiral bisoxazoline ligands (SPANbox) were found to be highly efficient in copper(II)‐ and zinc(II)‐catalyzed asymmetric chlorinations of cyclic β‐keto esters with N‐chlorosuccinimide (NCS) as the chlorination reagent, to give the corresponding α‐chloro‐β‐keto esters in excellent yields in 5–30 min with ee values up to 97%. The copper(II) triflate and zinc(II) triflate complexes of a single SPANbox ligand demonstrated complementary results to each other with respect to the enantioselection, affording both antipodes of the chlorinated product enantiomers with good to excellent optical purities. 相似文献
9.
Synthesis and Pharmacological Evaluation of α4β2 Nicotinic Ligands with a 3‐Fluoropyrrolidine Nucleus 下载免费PDF全文
Dr. Lucia Tamborini Dr. Andrea Pinto Dr. Roberta Ettari Dr. Cecilia Gotti Dr. Francesca Fasoli Prof. Paola Conti Prof. Carlo De Micheli 《ChemMedChem》2015,10(6):1071-1078
Nicotinic acetylcholine receptors (nAChRs) play an important role in many central nervous system disorders such as Alzheimer’s and Parkinson’s diseases, schizophrenia, and mood disorders. The α4β2 subtype has emerged as an important target for the early diagnosis and amelioration of Alzheimer’s disease symptoms. Herein we report a new class of α4β2 receptor ligands characterized by a basic pyrrolidine nucleus, the basicity of which was properly decreased through the insertion of a fluorine atom at the 3‐position, and a pyridine ring carrying at the 3‐position substituents known to positively affect affinity and selectivity toward the α4β2 subtype. Derivatives 3‐(((2S,4R)‐4‐fluoropyrrolidin‐2‐yl)methoxy)‐5‐(phenylethynyl)pyridine ( 11 ) and 3‐((4‐fluorophenyl)ethynyl)‐5‐(((2S,4R)‐4‐fluoropyrrolidin‐2‐yl)methoxy)pyridine ( 12 ) were found to be the most promising ligands identified in this study, showing good affinity and selectivity for the α4β2 subtype and physicochemical properties predictive of a relevant central nervous system penetration. 相似文献
10.
Philippe Diaz Dr. Sharangdhar S. Phatak Jijun Xu Dr. Frank R. Fronczek Fanny Astruc‐Diaz Charles M. Thompson Prof. Claudio N. Cavasotto Prof. Mohamed Naguib Prof. 《ChemMedChem》2009,4(10):1615-1629
We recently discovered and reported a series of N‐alkyl‐isatin acylhydrazone derivatives that are potent cannabinoid receptor 2 (CB2) agonists. In an effort to improve the druglike properties of these compounds and to better understand and improve the treatment of neuropathic pain, we designed and synthesized a new series of 2,3‐dihydro‐1‐benzofuran derivatives bearing an asymmetric carbon atom that behave as potent selective CB2 agonists. We used a multidisciplinary medicinal chemistry approach with binding mode prediction through ligand‐steered modeling. Enantiomer separation and configuration assignment were carried out for the racemic mixture for the most selective compound, MDA7 (compound 18 ). It appeared that the S enantiomer, compound MDA104 (compound 33 ), was the active enantiomer. Compounds MDA42 (compound 19 ) and MDA39 (compound 30 ) were the most potent at CB2. MDA42 was tested in a model of neuropathic pain and exhibited activity in the same range as that of MDA7. Preliminary ADMET studies for MDA7 were performed and did not reveal any problems. 相似文献
11.
Jiefeng Shen Delong Liu Qianjin An Yangang Liu Wanbin Zhang 《Advanced Synthesis \u0026amp; Catalysis》2012,354(17):3311-3325
(2S,3aR,7aS)‐Perhydroindolic acid, the key intermediate in the synthesis of trandolapril, and its trans‐isomers, were readily prepared. These proline‐like molecules are unique in that they contain a rigid bicyclic structure, with two hydrogen atoms trans to each other at the bridgehead carbon atoms. These molecules were used successfully as chiral organocatalysts in asymmetric domino Michael addition/cyclization reactions of aldehyde esters with β,γ‐unsaturated α‐keto esters. They proved to have excellent catalytic behavior, allowing for the synthesis of multi‐substituted, enantiomerically enriched hemiacetal esters. Under optimal conditions (using 10 mol% catalyst loading), a series of β,γ‐unsaturated α‐keto esters was examined with up to 99% de, ee and yield, respectively. Additionally, the enantiomerically enriched hemiacetal esters could be readily transformed into their corresponding bioactive pyrano[2,3‐b]pyrans (possessing a multi‐substituted bicyclic backbone). 相似文献
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In this paper, we report the synthesis, structure and electrical conductivity of Mo‐doped compounds with a nominal chemical formula of Ce1–xMoxO2+δ (x = 0.05, 0.07, 0.1) (CMO). The formation of fluorite‐like structure with a small amount of Ce8Mo12O49 impurity (JCPDS Card No. 31‐0330) was confirmed using a powder X‐ray diffraction (PXRD). The fluoride‐type structure was retained under wet H2 and CH4 atmospheres at 700 and 800 °C, while diffraction peaks due to metal Mo were observed in dry H2 under the same condition. AC impedance measurements showed that the total conductivity increases with increasing Mo content in CMO, and among the investigated samples, Ce0.9Mo0.1O2+δ exhibited the highest electrical conductivity with a value of 2.8 × 10–4 and 5.08 × 10–2 S cm–1 at 550 °C in air and wet H2, respectively. The electrical conductivity was found to be nearly the same, especially at high temperatures, in air, O2 and N2. Chemical compatibility of Ce0.9Mo0.1O2+δ with 10 mol‐% Y2O3 stabilised ZrO2 (YSZ) and Ce0.9Gd0.1O1.95 (CGO) oxide ion electrolytes in wet H2 was evaluated at 800–1,000 °C, using PXRD and EDX analyses. PXRD showed that CMO was found to react with YSZ electrolyte at 1,000 °C. The area specific polarisation resistance (ASPR) of Ce0.9Mo0.1O2+δ on YSZ was found to be 8.58 ohm cm2 at 800 °C in wet H2. 相似文献