- Electrochromism of fast photochromic radical complexes forming light-unresponsive stable colored radical cation
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We demonstrated the electrochromism of photochromic radical complexes containing triaryl imidazole: fast photoswitchable pentaarylbiimidazole (PABI) and the phenoxyl-imidazolyl radical complex (PIC). Cyclic voltammetry and spectroelectrochemistry revealed
- Yamamoto, Katsuya,Gomita, Isshu,Okajima, Hajime,Sakamoto, Akira,Mutoh, Katsuya,Abe, Jiro
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Read Online
- Diels-Alder Cycloaddition of C60 with Photochemically Generated Hydroxy to o-quinodimethanes Governed by Steric Factors: A Mechanistic Study
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Photoexcited o-alkyl-substituted benzaldehydes add to C60through their photoenol reactive intermediates producing stable [4 + 2] fullerene adducts. A mechanistic approach for this reactivity of C60 is provided, based mainly on intra-
- Roubelakis, Manolis M.,Malliaros, Nikitas G.,Orfanopoulos, Michael
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Read Online
- Stereoselective synthesis of all individual isomers of β-methyl-2',6'-dimethylphenylalanine
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Asymmetric synthesis of all four isomers of β-methyl-2',6'-dimethylphenylalanine was accomplished with complete stereoselectivities and high yields by using the Evans-like auxiliary 4-phenyl-oxazolidinone as a chiral auxiliary and as a chiral resolution reagent.
- Xiang,Wu,Hruby
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Read Online
- Palladium-catalysed annulative allylic alkylation for the synthesis of benzannulated heteroarenes
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A conceptually novel intramolecular allylic alkylation strategy is developed for the synthesis of carbazoles and dibenzothiophenes. In an unusual event, palladium catalyses the formation of π-allylpalladium complexes of the respective (2-methylindol-3-yl)allyl acetates and subsequently facilitates the benzannulation process. This journal is
- Yadav, Sonu,Ramasastry
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supporting information
p. 77 - 80
(2021/01/13)
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- PROCESS FOR PREPARING 2,6-DIALKYLPHENYLACETIC ACIDS
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The invention relates to a multi-stage process for preparing 2,6-dialkylphenylacetic acids of the general formula (I) by reacting 2,6-dialkylbromobenzenes with (1) magnesium, (2) a formamide, (3) an acid, (4) hydrogenation of the benzaldehyde obtained, (5
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Paragraph 0216-0219
(2022/01/04)
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- A Magnetically Recyclable Palladium-Catalyzed Formylation of Aryl Iodides with Formic Acid as CO Source: A Practical Access to Aromatic Aldehydes
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A magnetically recyclable palladium-catalyzed formylation of aryl iodides under CO gas-free conditions has been developed by using a bidentate phosphine ligand-modified magnetic nanoparticles-anchored- palladium(II) complex [2P-Fe 3O 4@SiO 2-Pd(OAc) 2] as catalyst, yielding a wide variety of aromatic aldehydes in moderate to excellent yields. Here, formic acid was employed as both the CO source and the hydrogen donor with iodine and PPh 3as the activators. This immobilized palladium catalyst can be obtained via a simple preparative procedure and can be facilely recovered simply by using an external magnetic field, and reused at least 9 times without any apparent loss of catalytic activity.
- You, Shengyong,Zhang, Rongli,Cai, Mingzhong
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p. 1962 - 1970
(2021/01/25)
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- Palladium-Catalyzed Reductive Carbonylation of (Hetero) Aryl Halides and Triflates Using Cobalt Carbonyl as CO Source
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An efficient protocol for the reductive carbonylation of (hetero) aryl halides and triflates under CO gas-free conditions using Pd/Co2(CO)8 and triethylsilane has been developed. The mild reaction conditions, enhanced chemoselectivity and, easy access to heterocyclic and vinyl carboxaldehydes highlights its importance in organic synthesis.
- Dogga, Bhushanarao,Joseph, Jayan T.,Kumar, C. S. Ananda
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supporting information
p. 309 - 313
(2020/12/23)
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- An aerobic oxidation of alcohols into carbonyl synthons using bipyridyl-cinchona based palladium catalyst
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We have reported an aerobic oxidation of primary and secondary alcohols to respective aldehydes and ketones using a bipyridyl-cinchona alkaloid based palladium catalytic system (PdAc-5) using oxygen at moderate pressure. ThePdAc-5catalyst was analysed using SEM, EDAX, and XPS analysis. The above catalytic system is used in experiments for different oxidation systems which include different solvents, additives, and bases which are cheap, robust, non-toxic, and commercially available on the industrial bench. The obtained products are quite appreciable in both yield and selectivity (70-85%). In addition, numerous important studies, such as comparisons with various commercial catalysts, solvent systems, mixture of solvents, and catalyst mole%, were conducted usingPdAc-5. The synthetic strategy of oxidation of alcohol into carbonyl compounds was well established and all the products were analysed using1H NMR,13CNMR and GC-mass analyses.
- Cheedarala, Ravi Kumar,Chidambaram, Ramasamy R.,Siva, Ayyanar,Song, Jung Il
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p. 32942 - 32954
(2021/12/02)
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- Continuous flow synthesis of aryl aldehydes by Pd-catalyzed formylation of phenol-derived aryl fluorosulfonates using syngas
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This communication describes the palladium-catalyzed reductive carbonylation of aryl fluorosulfonates (ArOSO2F) using syngas as an inexpensive and sustainable source of carbon monoxide and hydrogen. The conversion of phenols to aryl fluorosulfonates can be conveniently achieved by employing the inexpensive commodity chemical sulfuryl fluoride (SO2F2) and base. The developed continuous flow formylation protocol requires relatively low loadings for palladium acetate (1.25 mol%) and ligand (2.5 mol%). Good to excellent yields of aryl aldehydes were obtained within 45 min for substrates containing electron withdrawing substituents, and 2 h for substrates containing electron donating substituents. The optimal reaction conditions were identified as 120 °C temperature and 20 bar pressure in dimethyl sulfoxide (DMSO) as solvent. DMSO was crucial in suppressing Pd black formation and enhancing reaction rate and selectivity. This journal is
- Hanselmann, Paul,Hone, Christopher A.,Hu, Guixian,K?ckinger, Manuel,Kappe, C. Oliver
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p. 22449 - 22453
(2020/07/03)
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- Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas
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The reductive carbonylation of aryl iodides to aryl aldehydes possesses broad application prospects. We present an efficient and facile Rh-based catalytic system composed of the commercially available Rh salt RhCl3·3H2O, PPh3 as phosphine ligand, and Et3N as the base, for the synthesis of arylaldehydes via the reductive carbonylation of aryl iodides with CO and H2 under relatively mild conditions with a broad substrate range affording the products in good to excellent yields. Systematic investigations were carried out to study the experimental parameters. We explored the optimal ratio of Rh salt and PPh3 ligand, substrate scope, carbonyl source and hydrogen source, and the reaction mechanism. Particularly, a scaled-up experiment indicated that the catalytic method could find valuable applications in industrial productions. The low gas pressure, cheap ligand and low metal dosage could significantly improve the practicability in both chemical researches and industrial applications.
- Chen, Suqing,Liu, Zhenghui,Mu, Tiancheng,Wang, Peng,Yan, Zhenzhong,Yu, Dongkun,Zhao, Xinhui
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p. 645 - 656
(2020/05/14)
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- Synthesis method of phosphorescent materials of homoleptic Ir complex including DMP ligands using microwave
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The present invention relates to a synthesis method capable of synthesizing an iridium compound based on dimethylphenyl (DMP) ligand with high yield and excellent process efficiency. More specifically, the present invention relates to a synthesis method which applies a microwave reactor and is capable of securing significantly improved yields over previously known yields using an iridium dimer structure during a reaction.COPYRIGHT KIPO 2018
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Paragraph 0036; 0043-0047; 0086-0090; 0134-0138; 0182-0185
(2018/06/28)
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- Palladium/Rhodium Cooperative Catalysis for the Production of Aryl Aldehydes and Their Deuterated Analogues Using the Water–Gas Shift Reaction
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A novel Pd/Rh dual-metallic cooperative catalytic process has been developed to effect the reductive carbonylation of aryl halides in moderate to good yield. In this reaction, water is the hydride source, and CO serves both as the carbonyl source and the terminal reductant through the water–gas shift reaction. The catalytic generation of the Rh hydride allows for the selective formation of highly hindered aryl aldehydes that are inaccessible through previously reported reductive carbonylation protocols. Moreover, aldehydes with deuterated formyl groups can be efficiently and selectively synthesized using D2O as a cost-effective deuterium source without the need for presynthesizing the aldehyde.
- Ibrahim, Malek Y. S.,Denmark, Scott E.
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p. 10362 - 10367
(2018/07/31)
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- Reduction of N,N-Dimethylcarboxamides to Aldehydes by Sodium Hydride–Iodide Composite
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A new and concise protocol for selective reduction of N,N-dimethylamides into aldehydes was established using sodium hydride (NaH) in the presence of sodium iodide (NaI) under mild reaction conditions. The present protocol with the NaH-NaI composite allows for reduction of not only aromatic and heteroaromatic but also aliphatic N,N-dimethylamides with wide substituent compatibility. Retention of α-chirality in the reduction of α-enantioriched amides was accomplished. Use of sodium deuteride (NaD) offers a new step-economical alternative to prepare deuterated aldehydes with high deuterium incorporation rate. The NaH-NaI composite exhibits unique chemoselectivity for reduction of N,N-dimethylamides over ketones.
- Chan, Guo Hao,Ong, Derek Yiren,Yen, Zhihao,Chiba, Shunsuke
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- Rhodium-Catalyzed Formylation of Aryl Halides with CO2 and H2
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The reductive formylation of aryl iodides/bromides to aryl aldehydes using CO2/H2 is presented for the first time. It was realized over a catalytic system composed of RhI3 or RhI3/Pd(dppp)Cl2 (dppp = 1,3-bis(diphenyphosphino)propane) and PPh3 in the presence of Ac2O/Et3N at 100 °C, affording aromatic aldehydes in good to excellent yields, together with good functional-group tolerance and broad substrate scope. The reaction proceeds through three cascade steps, involving HCOOH formation, CO release, and formylation of aryl halides.
- Liu, Zhenghui,Yang, Zhenzhen,Yu, Bo,Yu, Xiaoxiao,Zhang, Hongye,Zhao, Yanfei,Yang, Peng,Liu, Zhimin
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supporting information
p. 5130 - 5134
(2018/09/13)
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- A process for preparing benzaldehyde and its derivatives
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The invention discloses a method for preparing benzaldehyde and its derivatives. The method comprises the following steps of in the presence of organic base and a palladium-containing catalyst, an iodobenzene compound shown in the formula I, CO2 and a hydrosilane compound undergo a reaction to produce a compound shown in the formula II. The method has the characteristics of mild reaction conditions, high efficiency and environmental friendliness. An experiment proves that the method for synthesis of benzaldehyde or its derivatives has a substrate conversion rate of 100% and a benzaldehyde or its derivative yield of 90% or more.
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Paragraph 0039; 0072; 0073
(2017/04/21)
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- Selective reduction of carboxylic acids to aldehydes with hydrosilane: Via photoredox catalysis
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The direct reduction of carboxylic acids to aldehydes with hydrosilane was achieved through visible light photoredox catalysis. The combination of both single electron transfer and hydrogen atom transfer steps offers a novel and convenient approach to selective reduction of carboxylic acids to aldehydes. The method also features mild conditions, high yields, broad substrate scope, and good functional group tolerance, such as alkyne, ester, ketone, amide and amine groups.
- Zhang, Muliang,Li, Nan,Tao, Xingyu,Ruzi, Rehanguli,Yu, Shouyun,Zhu, Chengjian
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supporting information
p. 10228 - 10231
(2017/09/22)
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- Ruthenium(0)-Catalyzed C-H Arylation of Aromatic Imines under Neutral Conditions: Access to Biaryl Aldehydes
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The first ruthenium(0)-catalyzed C-H bond arylation of aromatic imines with arylboronates under neutral conditions is reported. This versatile method provides rapid access to a wide range of biaryl aldehydes that are difficult to assemble using traditional methods with high atom economy. A new hydrogen acceptor for Ru(0) arylation has been identified. This atom-economical strategy has potential for an array of direct applications in Ru(0)-catalyzed C-H bond arylations using removable directing groups. An indole synthesis by a sequential one-pot, multiple C-H activation protocol is reported.
- Hu, Feng,Szostak, Michal
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supporting information
p. 4186 - 4189
(2016/09/09)
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- MAGNETICALLY SEPARABLE IRON-BASED HETEROGENEOUS CATALYSTS FOR DEHYDROGENATION OF ALCOHOLS AND AMINES
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The present invention discloses an iron-based nitrogen doped graphene catalyst, process for preparation thereof and use of said catalyst in oxidant-free catalytic dehydrogenation of alcohols and amines to the corresponding carbonyl compounds, amines and N-heterocylic compounds with extraction of molecular hydrogen as the only by-product.
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Page/Page column 15; 16; 17
(2016/12/22)
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- Formylation of electron-rich aromatic rings mediated by dichloromethyl methyl ether and TiCl4: Scope and limitations
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Here the aromatic formylation mediated by TiCl4 and dichloromethyl methyl ether previously described by our group has been explored for a wide range of aromatic rings, including phenols, methoxy- and methylbenzenes, as an excellent way to produce aromatic aldehydes. Here we determine that the regioselectivity of this process is highly promoted by the coordination between the atoms present in the aromatic moiety and those in the metal core.
- Ramos-Tomillero, Iván,Paradís-Bas, Marta,De Pinho Ribeiro Moreira, Ibério,Bofill, Josep María,Nicolás, Ernesto,Albericio, Fernando
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supporting information
p. 5409 - 5422
(2015/05/13)
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- Pd/C-catalyzed direct formylation of aromatic iodides to aryl aldehydes using carbon dioxide as a C1 resource
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Pd/C-catalyzed direct formylation of aromatic iodides to aryl aldehydes using CO2 as a C1 resource was realized for the first time in the presence of hydrosilanes and base DBU under mild conditions, giving a series of aldehydes in good yields. The Royal Society of Chemistry 2014.
- Yu, Bo,Zhao, Yanfei,Zhang, Hongye,Xu, Jilei,Hao, Leiduan,Gao, Xiang,Liu, Zhimin
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supporting information
p. 2330 - 2333
(2014/03/21)
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- A practical non-cryogenic process for the selective functionalization of bromoaryls
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A selective and practical bromine-metal exchange process under non-cryogenic conditions was developed by a simple modification of an existing protocol. By directly adding an alkyl lithium RLi reagent to a solution of a bromoaryl substrate ArBr and an alkylmagnesium reagent RMgX, a lithium triarylmagnesiate Ar3MgLi complex formed that allowed for various types of functionalization and more elaborate cross-coupling reactions. The simplicity and improved safety of the method represent a significant improvement over current state of the art that uses lithium trialkylmagnesiate R3MgLi complexes, and is especially advantageous for large-scale synthesis.
- Gallou, Fabrice,Haenggi, Ruedi,Hirt, Hans,Marterer, Wolfgang,Schaefer, Frank,Seeger-Weibel, Manuela
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p. 5024 - 5027
(2008/12/21)
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- Carbonylation of aryl halides: Extending the scope of the reaction
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Carbonylation reactions are being increasingly favoured in pharmaceutical chemistry for the atom-efficient introduction of carbonyl centres in aldehydes, acids, esters, and amides. Convenient procedures for simple aryl iodides and bromides are well established, and now the need is to develop improved conditions to allow the reactions to be extended to the more unreactive substrates, such as sterically hindered compounds and aryl chlorides. Sterically hindered compounds such as 2-iodo- or 2-bromo-m-xylenes can be converted using alkoxy and aminocarbonylation, while dehalogenation becomes a significant side reaction for reductive carbonylation. Less hindered compounds such as 2-iodo- or bromotoluene can be reacted successfully. Changing the aryl ligands of PdCl2{Ph2P(CH2)3PPh2} to alkyl groups improves the rate of oxidative addition but slows the carbonyl insertion step such that rates for the majority of aryl bromides are not improved by this change. Complexes such as PdCl2{Cy 2P(CH2)3PCy2} offer better performance for alkoxy and aminocarbonylation of aryl chlorides. However, for reductive carbonylation dehalogenation is a significant side reaction. Increasing CO pressure results in additional CO coordination to the catalytic intermediates and slows the reaction, while the dehalogenation is little affected, so reaction selectivity suffers. Thus, CO pressure is a critical parameter, particularly for reductive carbonylation, in achieving the optimum performance.
- Barnard, Christopher F.J.
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p. 566 - 574
(2013/01/03)
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- Reductive carbonylation - An efficient and practical catalytic route for the conversion of aryl halides to aldehydes
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Alternative routes for the introduction of aldehyde functionality are particularly desirable for fine chemical and pharmaceutical intermediates because of the wide range of further transformations that are possible. Catalytic processes are of particular interest for minimising waste, and therefore the reductive carbonylation of aryl halides has been explored. We have shown that high yields of aldehydes may be obtained for a wide selection of aryl iodides and bromides using mild conditions (3 bar of CO, temperatures 60-120°C) and silanes as hydride source. A choice of conditions (catalyst, base, solvent) is required to cover the range of aryl substituents varying in electron donation and steric influence. This is related to the competing needs of the several steps of this reaction, including oxidative addition, CO substitution, CO insertion, hydride transfer, and reductive elimination.
- Ashfield, Laura,Barnard, Christopher F. J.
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- Effects of aldehyde or dipyrromethane substituents on the reaction course leading to meso-substituted porphyrins
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To better understand the effects of diverse substituents on reactions leading to porphyrins, pyrrole+aldehyde condensations and related reactions of dipyrromethanes were examined. The course of pyrrole+aldehyde condensations was investigated by monitoring the yield of porphyrin (by UV-Vis spectroscopy), reaction of aldehyde (by TLC), and changes in the composition of oligomers (by laser desorption mass spectrometry). Reaction reversibility was examined via exchange experiments. Reversibility of reactions leading to porphyrin was further probed with studies of dipyrromethanes. The reaction course was found to depend on the nature of the substituent and the acid catalyst. Alkyl or electron-donating substituents displayed levels of reversibility (exchange/scrambling) on par or greater than that of the phenyl substituent, whereas electron-withdrawing or sterically bulky substituents exhibited little to no reversibility. The results obtained provide insight into the electronic and steric effects of different substituents and should facilitate the design of synthetic plans for preparing porphyrinic macrocycles. Graphical abstract.
- Geier III, G. Richard,Lindsey, Jonathan S.
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p. 11435 - 11444
(2007/10/03)
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- Substituted 1-(4-aminophenyl)pyrazoles and their use as anti-inflammatory agents
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1-(4-aminophenyl)pyrazoles optionally substituted on the 3- and 5-positions of the pyrazole ring and on the amino group at the 4-position of the phenyl ring are disclosed and described, which pyrazoles inhibit IL-2 production in T-lymphocytes.
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- Retroviral protease inhibiting compounds
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A compound comprising a substituent of the formula (II) is disclosed as an HIV protease inhibitor. Intermediates for making such compounds and processes for making such intermediates are also disclosed.
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- 2',6'-Dimethylphenoxyacetyl: A new achiral high affinity P3-P2 ligand for peptidomimetic-based HIV protease inhibitors
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Starting from palinavir (1), our lead HIV protease inhibitor, we have discovered a new series of truncated analogues in which the P3-P2 quinaldic-valine portion of 1 was replaced by 2',6'-dimethylphenoxyacetyl. With EC50's in the 1-2 nM range, some of these compounds are among the most potent inhibitors of HIV replication in vitro, reported to date. One of the most promising members in this series (compound 27, BILA 2185 BS) exhibited a favorable overall pharmacokinetic profile, with 61% apparent oral bioavailability in rat. X-ray crystal structures and molecular modeling were used to rationalize the high potency resulting from incorporation of this structurally simple, achiral ligand into the P3-P2 position of hydroxyethylamine-based HIV protease inhibitors.
- Beaulieu, Pierre L.,Anderson, Paul C.,Cameron, Dale R.,Croteau, Gilbert,Gorys, Vida,Grand-Ma?tre, Chantal,Lamarre, Daniel,Liard, Francine,Paris, William,Plamondon, Louis,Soucy, Fran?ois,Thibeault, Diane,Wernic, Dominik,Yoakim, Christiane,Pav, Susan,Tong, Liang
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p. 1094 - 1108
(2007/10/03)
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- RETROVIRAL PROTEASE INHIBITING COMPOUNDS
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A compound of the formula: STR1 is disclosed as an HIV protease inhibitor. Methods and compositions for inhibiting an HIV infection are also disclosed.
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- PALLADIUM-MEDIATED 2,6-DIALKYLATION OF N-BENZILIDINE IMINES: PREPARATION OF 2,6-DIALKYLBENZALDEHYDES
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Treatment of di-μ-trifluoroacetatobisdipalladium with two equivalents of primary alkyl iodides and subsequent hydrolysis provides an efficient route to 2,6-disubstituted benzaldehydes.
- McCallum, J. Stuart,Gasdaska, John R.,Liebeskind, Lanny S.
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p. 4085 - 4088
(2007/10/02)
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- INVESTIGATIONS ON REACTIONS OF CHLORINE DIOXIDE AND SODIUM CHLORITE WITH ORGANIC COMPOUNDS. PART XXXV. REACTIONS OF CHLORINE DIOXIDE WITH RING-SUBSTITUTED STYRENES
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Reactions of chlorine dioxide with ring substituted styrenes (1a-n) in carbon tetrachloride at 52-54 deg C were studied.The reaction products were isolated and characterised.It has been found that methyl-, chloro-, nitrostyrenes and 4-methoxystyrene are attacked by chlorine dioxide exclusively on the vinyl group, to yield the corresponding α-chloroacetophenones (2), diastereoisomers of β-chlorostyrene (6,7), oxidation products (8,9) and some polymers.Oxidation of its phenolic hydroxyl groups and vinyl polymerization took place in hydroxystyrenes.
- Kwiecien, Halina,Jalowiczor, Jozef
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p. 811 - 824
(2007/10/02)
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- Mechanism of the Chromium-Catalyzed Epoxidation of Olefins. Role of Oxochromium(V) Cations
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The catalytic epoxidation of various olefins with iodosylbenzene is efficiently carried out by a series of chromium(III) cations CrIII(salen)+ (I) which are promoted by pyridine N-oxide (pyO) and related oxygen donors as the cocatalyst.Analysis of the catalytic rate profile and products establish the oxochromium(V) derivative O=Cr(salen)+ (II) and its donor adduct O=Cr(salen)(pyO)+ (III) as the reactive intermediates in the catalytic cycle.The successful isolation as well as the complete spectral analysis and structural characterization by X-ray crystallography of both II and III reveal the basis for oxygen activation in the O=CrV functionality.The mechanism of oxygen atom transfer involves the rate-limiting attack on the olefin by the electrophilic oxochromium(V) cation.The observation of benzaldehyde as a byproduct derived from the pyO-promoted C=C cleavage of styrene provides a method for unequivocally proving the existence of a transient intermediate during oxygen atom transfer.Thus the rate of olefin oxidation is found to be completely independent of the product-forming steps leading to epoxide and benzaldehyde, as they are modulated by added pyO.Steric effects, isotopic 18O tracers, stereochemistry, skeletal rearrangement, and substituent effects all provide mechanistic probes for the structure of the metastable intermediate.
- Samsel, E. G.,Srinivasan, K.,Kochi, J. K.
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p. 7606 - 7617
(2007/10/02)
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- Ortho Metalation Directed by α-Amino Alkoxides
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The addition of aromatic aldehydes to certain lithium dialkylamides in benzene or tetrahydrofuran gave α-amino alkoxides which were ortho lithiated with excess n-butyllithium.Subsequent alkylation and hydrolysis provided ortho-substituted aromatic aldehydes via a one-pot reaction.The ortho metalation of α-amino alkoxides derived from 1- and 2-naphthaldehyde and various substituted benzaldehydes was examined.When N,N,N'-trimethylethylenediamine was used as the amine component of the α-amino alkoxide, metalation could be carried out at lower temperatures.This rate increase is due to an intramolecular TMEDA-like assisted metalation.The synthetic utility of this ortho metalation, including how varying the amine component of the α-amino alkoxide affects the regiochemistry and metalation rate, is discussed.
- Comins, Daniel L.,Brown, Jack D.
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p. 1078 - 1083
(2007/10/02)
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