- Copolymerization of carbon dioxide and propylene oxide catalyzed by two kinds of bifunctional salen-cobalt(III) complexes bearing four quaternary ammonium salts
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Two new bifunctional salen-cobalt(III) complexes were synthesized, which consist of salicylaldehyde bearing four quaternary ammonium salts and two different diamines. The copolymerization results indicated that decreasing temperature is advantageous for both the complexes. Of both the diamines, the complex 9 with o-diaminobenzene has a higher catalytic effect compared to complex 6 with 1,2-diaminocyclohexane. The catalytic effect of complex 9 is over 3.5 times than that of complex 6 at a temperature of 30°C. The research of PCO2 on the copolymerization revealed that the first-rank pressure was at 2 MPa for the two complexes. The highest turnover number are under conditions of T = 30°C, PCO2 = 2 MPa, and t = 24 hr. Differential scanning calorimeter curves indicated that poly(propylene carbonate) (PPC) by complex 9 has the highest Tg of 54.2°C. DTGA curves showed that there were two thermal degradation peaks, the first is for the ester bond, and the second is for the C–C bond.
- Du, Longchao,Wang, Chengze,Zhu, Weiju,Zhang, Jie
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- Design and synthesis of cage-like NADH model molecule intermediate with multi-chiral centers
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Studying NADH molecules is one of the most active areas in biomimetic research. It is important to design novel and efficient chiral NADH model molecules. Herein, a cage-like NADH model with multi-chiral centers was designed, and key intermediates have been synthesized. In this study, we found that pentafluorophenoxy group is an excellent leaving group for our synthetic route.
- Zhang, Tong,Bai, Cui-Bing,Wu, Yue-Hua,Wang, Nai-Xing,Xu, Bao-Cai,Yan, Zhan,Xing, Yalan
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supporting information
p. 410 - 416
(2019/02/05)
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- Spectroscopic exploration of binding of new imidazolium-based palladium(II) saldach complexes with CT-DNA as anticancer agents against HER2/neu overexpression
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The HER2/neu has shown a potential role in the choice of active chemotherapy for breast tumors because of its prognostic relevance and putative role in predicting drug resistance. Moreover, suppressing DNA replication has become an attractive strategy for treating cancer patients. In this attempt, the present study aimed to prepare new series of bis-imidazolium-based saldach {H2(Et)2saldach (nBu-Im+-X–)2} and their cis-Pd(II) complexes (saldach = N,N′-bis-(salicylidene)-R,R-1,2-diaminocyclohexane; X = Cl, PF6, BF4) as anticancer agents. The in vitro cytotoxicity activity of new cis-Pd(II) complexes against human breast adenocarcinoma cell lines (MCF-7) revealed higher growth-inhibitory effect than the native ligands. They induced a significant decrease for the protein HER2/neu expression with p 50 = 8.5 ± 0.2 μM) in inhibition of cell proliferation. Additionally, in vitro studies of Pd(II) complex (5a) using UV–Vis spectroscopy and binding affinity toward the calf thymus (CT) DNA) showed a combination of covalent, intercalation, hydrogen bonding interactions through formation of (CT-DNA).
- Alfaifi, Mohammad Y.,Elbehairi, Serag Eldin I.,Hafez, Hani S.,Elshaarawy, Reda F.M.
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p. 118 - 128
(2019/05/06)
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- Preparation method and application of trans-cyclohexanediamine tartrate
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The invention provides a preparation method of trans-cyclohexanediamine tartrate. The preparation method comprises the steps of charging, dropwise adding of trans-cyclohexanediamine, dropwise adding of glacial acetic acid, heat-insulation reaction and cooling. The invention further provides application of the trans-cyclohexanediamine tartrate in preparation of a schiff base metallic cobalt complex. The specific rotation of the prepared trans-cyclohexanediamine tartrate is minus 11 degrees to minus 13 degrees, the content is greater than or equal to 98.0%, and the appearance of the trans-cyclohexanediamine tartrate is off-white or light yellow crystal. The yield of the prepared trans-cyclohexanediamine tartrate is 55.8-56%; and reaction conditions are mild, and the preparation method is simple to operate, is carried out under normal pressure, and is high in safety.
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Paragraph 0020-0030
(2019/02/26)
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- Synthesis of N,N′-Dialkylated Cyclohexane-1,2-diamines and Their Application as Asymmetric Ligands and Organocatalysts for the Synthesis of Alcohols
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A series of N,N′-dialkylated derivatives of (1R,2R)-cyclohexane-1,2-diamine were synthesized, and a new approach to the one-pot preparation of this type of amine was demonstrated. The prepared diamines were used as organocatalysts for the two-step synthesis of α-hydroxy γ-keto esters from arenes, chlorooxoacetates, and ketones; they were also used as chiral ligands for Meervein-Ponndorf-Verley reductions and Henry reactions.
- Tsygankov, Alexey A.,Chun, Man-Seog,Samoylova, Alexandra D.,Kwon, Seongyeon,Kreschenova, Yuliya M.,Kim, Suhyeon,Shin, Euijin,Oh, Jinho,Strelkova, Tatyana V.,Kolesov, Valerii S.,Zubkov, Fedor I.,Semenov, Sergei E.,Fedyanin, Ivan V.,Chusov, Denis
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supporting information
p. 615 - 619
(2017/03/11)
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- A novel water-soluble highly selective “switch-on” ionic liquid-based fluorescent chemi-sensor for Ca(II)
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A novel chemi-sensor involve new bis-ionic Schiff base sensor (BISBS), N,N′-bis-[5-((2,4-lutidiniumchloride)methylene)-3-methoxysalicylidene]-R,R-1,2-cyclohexanediimine, has been synthesized and characterized. BISBS chemi-sensor was designed based on internal charge transfer (ICT) fluorescence mechanism. This new water soluble chemi-sensor provides great selectivity fluorescence detection for Ca(II) ions in an important physiological pH range. Moreover, the interaction of Ca(II) with the deprotonated BISBS to produce a metal-ligand complex with a ratio of (1: 1) accompanying with an enhancement in the intensity of emission band located at 502?nm. Fluorescence switching-on during the chemical interaction between BISBS and Ca(II) ions is very easily noticed with naked eye, but other metal cations such as alkali, alkaline earth and transition metal don't give any fluorescence changes. The novel developed BISBS sensor successively offers low limit of detection (LOD) 1.5?nM and fast tracing of Ca(II) in the physiological pH?7.6. Thus BISBS may provide a novel auspicious methodology for detection calcium cations in the environmental and biological samples.
- Elshaarawy, Reda F.M.,Ali, Reham,Saleh, Sayed M.,Janiak, Christoph
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p. 308 - 315
(2017/06/19)
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- Asymmetric Grignard Synthesis of Tertiary Alcohols through Rational Ligand Design
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A simple, general and practical method is reported for highly enantioselective construction of tertiary alcohols through the direct addition of organomagnesium reagents to ketones. Discovered by rational ligand design based on a mechanistic hypothesis, it has an unprecedented broad scope. It utilizes a new type of chiral tridentate diamine/phenol ligand that is easily removed from the reaction mixture. It is exemplified by application to a formal asymmetric synthesis (>95:5 d.r.) of vitamin E.
- Bieszczad, Bartosz,Gilheany, Declan G.
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supporting information
p. 4272 - 4276
(2017/04/03)
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- METHOD OF PRODUCING OPTICALLY ACTIVE TRANS-1,2-DIAMINOCYCLOHEXANE
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A method produces optically active trans-1,2-diaminocyclohexane, in which a crystal of optically active trans-1,2-diaminocyclohexane is obtained by crystallization from a solution of optically active trans-1,2-diaminocyclohexane. Optically active trans-1,2-diaminocyclohexane with high purity is obtained in a favorable yield from a solution of optically active trans-1,2-diaminocyclohexane. The optically active trans-1,2-diaminocyclohexane with high purity is useful as a raw material for a large number of medicines.
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Paragraph 0057
(2016/02/28)
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- Preparation of C 2-Symmetric Biaryl Bisiminium Salts and Their Use as Organocatalysts for Asymmetric Epoxidation
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Two C 2-symmetric bisiminium salt species containing biphenylazepinium units and derived from two chiral diamines were prepared and tested as organocatalysts for asymmetric epoxidation.
- Bulman Page, Philip C.,Farah, Mohamed M.,Buckley, Benjamin R.,Chan, Yohan,Blacker, A. John
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supporting information
p. 126 - 130
(2015/12/26)
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- Catalytic and mechanistic studies into the epoxidation of styrenes using manganese complexes of structurally similar polyamine ligands
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Two structurally similar polyamine ligands (7 and 8) have been prepared, which differ only by the presence of either a secondary or tertiary nitrogen donor within their N5 donor set. The ligands, in combination with iron and manganese salts, have been screened for their efficacy as catalysts for the epoxidation of styrene, using both hydrogen peroxide and peracetic acid as oxidants. Clear differences in activity between the two systems were observed, with 7 proving most effective in the presence of MnSO4 with H 2O2, whereas ligand 8 proved to be effective with Mn(OTf)2, MnCl2 and Mn(ClO4)2 using peracetic acid as the oxidant. A Hammett analysis of the initial rate kinetics of the optimal systems, combined with analysis by UV-vis spectroscopy, indicates that the small structural differences in the ligands elicit profound changes in the nature of the active species formed. The Royal Society of Chemistry.
- Ilyashenko, Gennadiy,De Faveri, Giorgio,Follier, Thomas,Al-Safadi, Rawan,Motevalli, Majid,Watkinson, Michael
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p. 1124 - 1134
(2014/02/14)
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- Direct asymmetric aldol reaction of cyclohexanone with aldehydes catalyzed by chiral trans-cyclohexanediamine l-tartrate salt
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The stable and commercially available catalyst (1R,2R)-(+)-1,2- cyclohexanediamine l-tartrate complex was used for asymmetric aldol reaction in high yields (up to 99 %) and enantioselectivities [up to 94 % enantiomeric excess (ee)]. The catalyst was obtai
- Wu, Shengying,Wang, Limin,Tang, Jun,Mao, Dan,Liu, Xin
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p. 381 - 386
(2013/05/21)
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- New cyclic aminals derived from rac-trans-1,2-diaminocyclohexane: Synthesis and crystal structure of racemic 1,8,10,12-tetraazatetracyclo[8.3.1.1. 8,1202,7] pentadecane and a route to its enantiomerically pure (R,R) and (S,S) isomers
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New enantiomerically pure macrocyclic aminals (2R,7R)- and (2S,7S)-1,8,10,12-tetraazatetracyclo[8.3.1.1.8,120 2,7]pentadecane (4a and 4b) were obtained by a three component reaction between their respective pure enantiomer of trans-1,2- diaminocyclohexane, ammonia, and formaldehyde. Additionally, the X-ray structure of the racemic compound 4 and the specific rotations of the racemic and optically pure compounds were determined. To further understand the synthetic utilities of enantiomers 4a and 4b, Mannich-type reactions with 1H-benzotriazole were performed, affording (3aR,7aR)- and (3aS,7aS)-1,1′-{[2,3,3a,4,5,6,7, 7a-octahydro-1H-1,3-benzimidazole-1,3-diyl]bis(methylene)}bis-1H-benzotriazole (9 and 10) and allowing for new possibilities related to the preparation of chiral ligands for asymmetric catalysis.
- Rivera, Augusto,Quiroga, Diego,Jiménez-Cruz, Leonardo,Fejfarová, Karla,Du?ek, Michal
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body text
p. 345 - 348
(2012/02/01)
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- Ready available chiral azapyridinomacrocycles n-oxides; First results as lewis base catalysts in asymmetric allylation of p-nitrobenzaldehyde
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We report here the straightforward synthesis of the first series of enantiomerically pure azapyridinomacrocycles N-oxides containing a cyclohexyl chiral moiety. These compounds were readily obtained in good overall yields by a convergent synthesis using natural amino acids as starting building blocks and macrocyclisation as the key step. This method is rapid, efficient and suitable for the introduction of various substituents at the macrocyclic skeleton. Finally, the compounds were tested as organocatalysts for the enantioselective allylation of p-nitrobenzaldehyde with allyltrichlorosilane.
- Veitia, Maite Sylla-Iyarreta,Joudat, Mounia,Wagner, Mathieu,Falguieres, Annie,Guy, Alain,Ferroud, Clotilde
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body text
p. 2011 - 2039
(2011/10/19)
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- When is an imine not an imine? Unusual reactivity of a series of Cu(ii) imine-pyridine complexes and their exploitation for the Henry reaction
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In this paper we report the synthesis and solid-state structures for a series of pyridine based Cu(ii) complexes and preliminary data for the asymmetric Henry reaction. Interestingly, the solid-state structures indicate the incorporation of an alcohol into one of the imine groups of the ligand, forming a rare α-amino ether group. The complexes have been studied via single crystal X-ray diffraction, EPR spectroscopy and mass spectrometry. Intriguingly, it has been observed that the alcohol only adds to one of the imine moieties. Density functional theory (DFT) calculations have also been employed to rationalise the observed structures. The Cu(ii) complexes have been tested in the asymmetric Henry reaction (benzaldehyde + nitromethane or nitroethane) with ee's up to 84% being achieved as well as high conversions and modest diastereoselectivities. The Royal Society of Chemistry 2011.
- Cooper, Christine J.,Jones, Matthew D.,Brayshaw, Simon K.,Sonnex, Benjamin,Russell, Mark L.,Mahon, Mary F.,Allan, David R.
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supporting information; experimental part
p. 3677 - 3682
(2011/07/30)
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- Reducing the cost of production of bimetallic aluminium catalysts for the synthesis of cyclic carbonates
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Bimetallic aluminium complexes of general formula [(salen)Al]2O or [(acen)Al]2O catalyse the formation of cyclic carbonates from carbon dioxide and terminal epoxides under exceptionally mild reaction conditions. To improve the potential for industrial scale application of these catalysts, the cost of their production has been evaluated and reduced significantly by optimization of the synthesis, including replacement of the most expensive chemicals by less expensive alternatives. The largest cost saving was associated with the formation of aluminium triethoxide insitu, which reduced the cost of the chemicals need for production of the catalysts by 49-87%. Further savings were made by avoiding the use of tetrabutylammonium bromide and acetonitrile, resulting in overall cost savings of 68-93%. Copyright
- North, Michael,Young, Carl
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scheme or table
p. 1685 - 1693
(2012/03/10)
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- Enantioselective reduction of α-substituted ketones mediated by the boronate ester TarB-NO2
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A facile and mild reduction procedure is reported for the preparation of chiral secondary alcohols prepared from α-substituted ketones using sodium borohydride and the chiral boronate ester (l)-TarB-NO2. Direct reduction of substituted ketones bearing Lewis basic heteroatoms generally provided secondary alcohols of only modest enantiomeric excess likely due to either competition between the target carbonyl and the functionalized sidechains at the Lewis acidic boron atom in TarB-NO2 or the added steric bulk of the α-sidechain. As an alternative method, these substrates were synthesized using TarB-NO2 via a two-step procedure involving the reduction of an α-halo ketone to a chiral terminal epoxide, followed by regioselective/regiospecific epoxide opening by various nucleophiles. This procedure provides access to a variety of functionalized secondary alcohols including β-hydroxy ethers, thioethers, nitriles, and amines with enantiomeric excesses of 94% and yields up to 98%.
- Eagon, Scott,Ball-Jones, Nicholas,Haddenham, Dustin,Saavedra, Jaime,Delieto, Cassandra,Buckman, Matthew,Singaram, Bakthan
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supporting information; experimental part
p. 6418 - 6421
(2010/12/30)
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- Salen manganese (III) complexes as catalysts for R-(+)-limonene oxidation
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The epoxidation of R-(+)-limonene using in situ generated dimethyldioxirane (DMD) as the oxidizing agent and four Jacobsen-type catalysts ((R,R)-Jacobsen, (S,S)-Jacobsen, racemic Jacobsen and achiral Jacobsen) was examined. The effect of the amount of KHSO5 and acetone in the catalyzed and un-catalyzed reaction was also assessed. The main reaction products were diepoxide and endocyclic monoepoxide. In the absence of catalyst, the amount of KHSO5 did not significantly influence conversion and selectivity. The catalyst can be segregated to a different phase and separated from the reaction media when the amount of KHSO5 is above the stoichiometric ratio, R-(+)-limonene/KHSO5 = 0.5 mmol/mmol, and acetone/mmol R-(+)-limonene = 2 mL/mmol. However, when the amount of KHSO5 is below the stoichiometric ratio (R-(+)-limonene/KHSO5 = 1.5 mmol/mmol) the catalyst is difficult to separate. Under the reaction conditions of this study, when the catalyst is segregated, no effect of the catalyst chiral center, (R,R)-Jacobsen or (S,S)-Jacobsen, was found on conversion and selectivity. Additionally, the (R,R)-Jacobsen's catalyst proved to be very stable to oxidative degradation.
- Cubillos, Jairo,Vásquez, Santiago,Montes de Correa, Consuelo
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experimental part
p. 57 - 65
(2010/10/02)
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- A new sparteine surrogate for asymmetric deprotonation of N-Boc pyrrolidine
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(Chemical Equation Presented) The s-BuLi complex of a cyclohexane-derived diamine is as efficient as s-BuLi/(-)-sparteine for the asymmetric deprotonation of N-Boc pyrrolidine. This is the first example of high enantioselectivity using a non-sparteine-like diamine in such reactions. The ( S, S)-diamine is a useful (+)-sparteine surrogate and was utilized in short syntheses of (-)-indolizidine 167B and an intermediate for the synthesis of the CCK antagonist (+)-RP 66803.
- Stead, Darren,O'Brien, Peter,Sanderson, Adam
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supporting information; experimental part
p. 1409 - 1412
(2009/04/12)
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- Instantaneous low temperature gelation by a multicomponent organogelator liquid system based on ammonium salts
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A new synergistic multicomponent organogelator liquid system (MOGLS) was discovered during the standard protocol of tartaric acid-mediated racemic resolution of (±)-trans-1,2-diaminocyclohexane. The MOGLS is formed by a 0.126 M methanolic solution of (1R,2R)-(+)-1,2-diaminocyclohexane L-tartrate and 1 equiv of concentrated hydrochloric acid. Nonreversible gelation of oxygenated and nitrogenated solvents occurs efficiently at low temperature. Several features make this system unique: (1) it is a multicomponent solution where each of the five components is required for the organogelation property; (2) the multicomponent organogelator liquid system (MOGLS) is formed by simple, small, and commercially available chiral building blocks dissolved in a well-defined solvent system (MeOH/HCl/H2O); (3) the chiral building blocks are easily amenable for further modifications in structure-property relationship studies; (4) the gelation phenomenon takes place efficiently at low temperature upon warming up the isotropic solution, conversely to the typical gel preparation protocol (gel formation upon cooling down the isotropic solution); (5) the formed organic gels are not thermoreversible in spite of the noncovalent interactions that hold the 3D-fibrillar network together.
- Velázquez, Daniel García,Díaz, David Díaz,Ravelo, ángel Gutiérrez,Tellado, José Juan Marrero
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supporting information; experimental part
p. 7967 - 7973
(2009/02/02)
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- In vivo studies of a platinum(II) metallointercalator
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An in vivo study for determining the toxicity and efficacy of [Pt(S,S-dach)(phen)Cl2·1.5H2O·0.5HCl (PHENSS) in female Specific Pathogen Free (SPF) Swiss nude mice bearing PC3 tumour xenografts revealed PHENSS to be non-toxic and effective in decreasing tumour growth. The Royal Society of Chemistry.
- Fisher, Dianne M.,Fenton, Ronald R.,Aldrich-Wright, Janice R.
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supporting information; experimental part
p. 5613 - 5615
(2009/04/12)
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- PREPARATION OF PLATINUM(II) COMPLEXES
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This invention relates to a method for the preparation of a platinum(II) complex containing a neutral bidentate ligand, such as oxaliplatin. The method includes the step of reacting a halogenoplatinum complex containing a neutral bidentate ligand with an oxalate salt in a solvent, wherein more than 1 g/L of the oxalate salt is soluble in the solvent. The invention also relates to new platinum(II) complexes.
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Page/Page column 17
(2008/06/13)
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- Mechanistic aspects of the copolymerization reaction of carbon dioxide and epoxides, using a chiral salen chromium chloride catalyst
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The air-stable, chiral (salen)CrIIICI complex (3), where H2salen = N, N-bis(3,5-di-tert-butyl-salicylidene)-1,2-cyclohexene diamine, has been shown to be an effective catalyst for the coupling of cyclohexene oxide and carbon dioxide
- Darensbourg, Donald J.,Yarbrough, Jason C.
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p. 6335 - 6342
(2007/10/03)
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- Enantioselective Diels-Alder reactions of optically active (buta-1,3-dien-2-yl)(salen)cobalt(iii) complexes
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The syntheses of two optically active (buta-1,3-dien-2-yl)(salen)Co complexes are reported. These dienyl complexes undergo Diels-Alder reactions with high enantioselectivity with a variety of dienophiles. One of the (salen)Co-substituted Diels-Alder cyclo
- Chapman, John J.,Day, Cynthia S.,Welker, Mark E.
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p. 2273 - 2282
(2007/10/03)
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- Enantioselective addition of diethylzinc to benzaldehyde catalyzed by chiral titanate complexes with helical ligands
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Enantioselective alkylation of benzaldehyde with Et2Zn has been studied. This reaction is catalyzed by helical titanium complexes of tetradentate ligands and has been found to give good to excellent enantioselectivities.
- Guo, Cheng,Qiu, Jun,Zhang, Xumu,Verdugo, Dawn,Larter, Martin L.,Christie, Ray,Kenney, Patrick,Walsh, Patrick J.
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p. 4145 - 4158
(2007/10/03)
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