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General Synthesis (general + synthesis)
Selected AbstractsEfficient and General Synthesis of 3-Aminoindolines and 3-Aminoindoles via Copper-Catalyzed Three-Component Coupling ReactionADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2010Dmitri Chernyak Abstract An efficient three-component coupling (TCC) reaction toward a variety of 3-aminoindoline and 3-aminoindole derivatives has been developed. This cascade transformation proceeds via the copper-catalyzed coupling reaction between 2-aminobenzaldehyde, a secondary amine, and an alkyne leading to a propargylamine intermediate which, under the reaction conditions, undergoes cyclization into the indoline core. The latter, upon treatment with a base, smoothly isomerizes into the indole. Alternatively, the indole can directly be synthesized in a one-pot sequential reaction. [source] ChemInform Abstract: A Facile and General Synthesis of Tropolonyl-Substituted Chalcone DerivativesCHEMINFORM, Issue 42 2010Mingqin Chang Abstract via Claisen,Schmidt condensation of 3-acetyltropolone with aromatic aldehydes under mild conditions (22 examples) [source] ChemInform Abstract: A General Synthesis of 4-Arylaminoquinazoline-2-carbonitriles.CHEMINFORM, Issue 47 2009Kamal M. El-Shaieb Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Reaction of Benzyne with Salicylaldehydes: General Synthesis of Xanthenes, Xanthones, and Xanthols.CHEMINFORM, Issue 19 2009Kentaro Okuma Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A New General Synthesis of N-Hydroxyindoles.CHEMINFORM, Issue 16 2008Michel Belley Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] An Efficient, Facile, and General Synthesis of 1H-Indazoles by 1,3-Dipolar Cycloaddition of Arynes with Diazomethane Derivatives.CHEMINFORM, Issue 35 2007Tienan Jin Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Control of Stereochemistry: A General Synthesis of cis- or trans-,,,-Disubstituted-,-butyrolactones Following (Z)-Crotylboration.CHEMINFORM, Issue 51 2006P. Veeraraghavan Ramachandran Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] A General Synthesis of N-Aryl- and N-Alkyl-2-aminobenzoxazoles.CHEMINFORM, Issue 9 2006Zhenping Tian Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] General Synthesis of (1-Substituted-1H-1,2,3-triazol-4-ylmethyl)-dialkylamines via a Copper(I)-Catalyzed Three-Component Reaction in Water.CHEMINFORM, Issue 52 2005Ze-Yi Yan Abstract For Abstract see ChemInform Abstract in Full Text. [source] An Efficient and General Synthesis of Indolo[2,3-a]carbazoles Using the Fischer Indole SynthesisCHEMINFORM, Issue 22 2005Yong-Zhou Hu Abstract For Abstract see ChemInform Abstract in Full Text. [source] Sequential Ring-Closing Metathesis/Pd-Catalyzed, Si-Assisted Cross-Coupling Reactions: General Synthesis of Highly Substituted Unsaturated Alcohols and Medium-Sized Rings Containing a 1,3-cis,cis Diene Unit.CHEMINFORM, Issue 5 2005Scott E. Denmark Abstract For Abstract see ChemInform Abstract in Full Text. [source] A General Synthesis of N-Reverse-Prenyl Indoles.CHEMINFORM, Issue 42 2004Fumiaki Yokokawa Abstract For Abstract see ChemInform Abstract in Full Text. [source] Ring-Opening Reactions of Iminosugar-Derived Aziridines: Application to the General Synthesis of ,-1-C-Substituted Derivatives of Fagomine.CHEMINFORM, Issue 43 2003Jean-Yves Goujon Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: The First Reliable, General Synthesis of the 5-Oxo Derivatives of 5,6-Dihydro-1,2,4-triazolo[4,3-c]pyrimidine and the Rates of Isomerization of the [4,3-c] Compounds into Their [1,5-c] Isomers.CHEMINFORM, Issue 34 2002Tomohisa Nagamatsu Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A General Synthesis of Dioxolenone Prodrug Moieties.CHEMINFORM, Issue 21 2002Chong-Qing Sun Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Intermolecular Pauson,Khand Reactions of Cyclopropene: A General Synthesis of Cyclopentanones.CHEMINFORM, Issue 8 2002Iolanda Marchueta Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Facile and General Synthesis of Pyrrolo[2,3-b]pyrazines via 2-(Dicyanoylidene)-3-halopyrazines.CHEMINFORM, Issue 1 2002Igor L. Yudin Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: General Synthesis of ,-Functionalized ,-Aryl-Substituted Primary Nitro Compounds.CHEMINFORM, Issue 41 2001A. A. Tishkov Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] General Synthesis and Aggregation Behaviour of New Single-Chain Bolaphospholipids: Variations in Chain and Headgroup StructuresCHEMISTRY - A EUROPEAN JOURNAL, Issue 22 2008Simon Drescher Abstract The chemical structures of polymethylene-1,,-bis(phosphocholines) that self-assemble into nanofibres was modified on the one hand in the hydrophobic chain region, by introduction of sulfur and oxygen atoms, and on the other hand by variation of the polar headgroup structure with functionalised tertiary amines. The temperature-dependent self-assembly of these novel bolaphospholipids into nanofibres and spherical micelles was investigated by differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The thermal stabilities of the nanofibres strongly depend on the chemical compositions of the headgroups and of the hydrophobic chains. The insertion of new functionalities in the headgroup region by click chemistry makes these substances interesting for potential applications in bioscience and materials science. [source] General Synthesis and Aggregation Behaviour of a Series of Single-Chain 1,,-Bis(phosphocholines)CHEMISTRY - A EUROPEAN JOURNAL, Issue 18 2007Simon Drescher Abstract The synthesis and physicochemical characterisation of a series of polymethylene-1,,-bis(phosphocholines) with even-numbered chain lengths between 22 and 32 carbon atoms is described. Two new synthetic strategies for the preparation of long-chain 1,,-diols as hydrocarbon building blocks are presented. The temperature-dependent self-assembly of the single-chain bolaamphiphiles was investigated by cryo transmission electron microscopy (cryo-TEM), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). [source] N -Acetylation as a Means to Activate Polyfluoroarylamines for Selective ortho -Hydrodefluorination by Zinc in Aqueous Ammonia: A Concise Route to Polyfluorobenzo Azaheterocycles,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 2 2007Sergey S. Laev Abstract N -Acetylation of polyfluoroarylamines is proposed as a meansto remove the amino group blocking effect of their hydrodefluorination by zinc in aqueous ammonia. With pentafluoroacetanilide, the Zn ion specific effect has been demonstrated to be responsible for ortho hydrodefluorination. This regiochemistry is accompanied by the removal of a fluorine atom from the para position, which occurs predominantly in the initial phase of the process in the absence of deliberately added zinc salt. The CuCl2 additive has been found to accelerate the reaction and to propel it to double defluorination. Quantum chemical calculations suggest a diminished electron affinity of pentafluoroaniline, which is responsible for its inertness in relation to the hydrodefluorination reaction. The pentafluoroaniline radical anion, which essentially has a nonplanar structure, is prone to easy fragmentation to give an aminotetrafluorophenyl radical. For pentafluoroacetanilide, CVA experiments and quantum chemical calculations predict that the pentafluorophenyl moiety serves as the electron receptor and that the acetamido group is twisted out of coplanarity with the benzene ring; thus, together with the electron-withdrawing effect of the acetyl group, the amino group blocking effect is suppressed. On this ground, the selective ortho hydrodefluorination of polyfluoroacetanilides is developed as an important protocol for the expeditious and general synthesis of polyfluorobenzo azaheterocycles via readily accessible polyfluoroarylamines from base polyfluoroarenes. Its applicability has been illustrated by preparing quinolines that possess a polyfluorinated benzene moiety by the Skraup synthesis utilizing crude polyfluoroacetanilide hydrodefluorination products as starting materials. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] An Improved Synthesis of Procyanidin Dimers: Regio- and Stereocontrol of the Interflavan BondEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2006Isabelle Tarascou Abstract A direct and general synthesis of procyanidin dimers B1, B2, B3 and B4 (10a,d) is presented. The approach is based on the stoichiometric coupling of two protected monomeric units (the nucleophilic 2a,b and electrophilic 4a,b partners) and deals with the regio- and stereocontrol of the C4,C8 interflavan bond as well as the control of the degree of oligomerization. The synthesis involves a five-step pathway starting from the native catechin (1a) or epicatechin (1b) to the fully deprotected dimers 10a,d. Furthermore, the process appears to be iterative as the coupling intermediates 9a,d themselves can be readily used in further selective syntheses of trimers or higher oligomers. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Recent Progress in Syntheses and Applications of Dumbbell-like NanoparticlesADVANCED MATERIALS, Issue 30 2009Chao Wang Abstract This paper reviews the recent research progress in the syntheses and applications of dumbbell-like nanoparticles (NPs). It first describes the general synthesis of dumbbell-like NPs that contain noble metal and magnetic NPs/or quantum dots. It then outlines the interesting optical and magnetic properties found in these dumbbell NPs. The review further highlights several exciting application potentials of these NPs in catalysis and biomedicine. [source] Patterns of population genetic diversity in riparian and aquatic plant species along riversJOURNAL OF BIOGEOGRAPHY, Issue 9 2010Olivier Honnay Abstract Aim, The downstream hydrochoric spread of seeds of aquatic and riparian plant species, without upstream compensation, can be expected to result in downstream accumulation of population genetic diversity. This idea has been termed the ,unidirectional dispersal hypothesis' and is the genetic equivalent of the more generally known ,drift paradox'. Our aim was to test this unidirectional diversity hypothesis, and to present a general synthesis of the patterns of population genetic variation across different riparian and aquatic plant species along rivers. Location, The Meuse River (Belgium) and rivers world-wide. Methods, First, we used amplified fragment length polymorphism markers to compare patterns of within- and between-population genetic diversity among three riparian plant species (Sisymbrium austriacum, Erysimum cheiranthoides and Rorippa sylvestris), typically occurring in different habitats along a gradient perpendicular to the Meuse River. Second, we performed a meta-analysis on studies reporting on the population genetic structure of riparian and aquatic plant species along rivers. Results, Along the Meuse River, we found significant genetic differentiation among populations of all three riparian species, and significant isolation by distance for one of them (R. sylvestris). There was no clear association between the typical habitat of a species and its population genetic structure. None of the three species provided evidence for the unidirectional dispersal hypothesis. The meta-analysis, based on 21 data records, did not support the unidirectional dispersal hypothesis either. Average weighted population genetic differentiation across species was significant. Main conclusions, Important mechanisms of upstream seed dispersal, probably through zoochory, together with higher seed recruitment opportunities in upstream habitats due to density dependence of recruitment, may explain the absence of downstream accumulation of genetic diversity. Also, it seems difficult to find consistent patterns in genetic variation in species from aquatic and riparian habitats. We argue that this is due to the recurrent extinctions and colonizations characteristic of these habitats, resulting in complex genetic patterns. Our results strongly support previous suggestions that stream ecology should consistently embrace metapopulation theory to be able to understand patterns of genetic diversity, as well as species diversity. [source] Backbone amide linker (BAL) strategy for N, -9-fluorenylmethoxycarbonyl (Fmoc) solid-phase synthesis of peptide aldehydes,JOURNAL OF PEPTIDE SCIENCE, Issue 9 2005Joseph C. Kappel Abstract A rapid and efficient strategy has been developed for the general synthesis of complex peptide aldehydes. N, -Benzyloxycarbonylamino acids were converted to protected aldehyde building blocks for solid-phase synthesis in four steps and moderate overall yields. The aldehydes were protected as 1,3-dioxolanes except for one case where a dimethyl acetal was used. These protected amino aldehyde monomers were then incorporated onto 5-[(2 or 4)-formyl-3,5-dimethoxyphenoxy]butyryl-resin (BAL-PEG-PS) by reductive amination, following which the penultimate residue was introduced by HATU-mediated acylation. The resultant resin-bound dipeptide unit, anchored by a backbone amide linkage (BAL), was extended further by routine Fmoc chemistry procedures. Several model peptide aldehydes were prepared in good yields and purities. Some epimerization of the C -terminal residue occurred (10% to 25%), due to the intrinsic stereolability conferred by the aldehyde functional group, rather than any drawbacks to the synthesis procedure. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd. [source] Experimental design and taxonomic scope of fragmentation studies on European mammals: current status and future prioritiesMAMMAL REVIEW, Issue 2 2010Alessio MORTELLITI ABSTRACT 1Habitat loss, habitat fragmentation and habitat degradation are the greatest threats to mammals in Europe and the rest of the world. Despite the fact that extensive literature exists, no comprehensive review or synthesis is available to date and this may slow down scientific progress and hamper conservation efforts. 2The goal of this study is to understand if and in what direction progress has been made in the study of the effects of habitat loss and fragmentation on the spatial distribution of European terrestrial mammals. Firstly, we carry out a general synthesis which is structured around 11 key points. The aim of this point-by-point analysis is to identify trends, knowledge gaps and any significant bias in the available literature, and to highlight strengths and shortfalls of the different approaches which have to date been applied. Secondly, we follow a species-specific systematic approach: for each species, we synthesise key results. 3Our results show how substantial progress has been hampered for several reasons including: a large predominance of small-scale field studies of short duration, and a generalised lack of control of: (i) confounding variables; (ii) spatial autocorrelation; and (iii) false absences. Also, despite the relatively high number of studies, few were theoretical studies and even fewer were meta-analyses. The lack of meta-analyses is likely to be due to the small amount of crucial details included in the publications, such as model parameters or information on the landscape context (such as the amount of residual forest cover). 4We synthesise the main results for 14 species. The level of progress is highly variable: for some species, such as the red squirrel Sciurus vulgaris, a series of long-term, large-scale process-oriented studies has allowed an in-depth understanding of its ecology in fragmented landscapes. On the other hand, with other species such as the bank vole Myodes glareolus, despite a relatively large number of field studies, little progress has been made. [source] ChemInform Abstract: Synthesis of ,-Alkylidene-,-valerolactones via the Conjugate Addition of Ketone Enolates to Functionalized Allyl Acetates.CHEMINFORM, Issue 35 2010P. Veeraraghavan Ramachandran Abstract A general synthesis of differently substituted ,-alkylidene-,-valerolactones via the conjugate addition-elimination of functionalized allylic acetates (I) with enolate nucleophiles (II),(V), and (IX) is achieved. [source] Use of ,,,-Unsaturated ,-Ketocarbonyls for a Totally Regioselective Oxidative Multicomponent Synthesis of Polyfunctionalized PyridinesCHEMISTRY - A EUROPEAN JOURNAL, Issue 47 2009Christophe Allais Versatile partners: ,-Ketocarbonyls have been shown for the first time to be versatile partners in a Michael addition promoted oxidative domino three-component reaction under heterogeneous conditions. This multicomponent reaction sequence led to the development of a general synthesis of highly functionalized pyridines (see scheme), allowing selective and simultaneous incorporation of a substituent at the 4-position and a synthetically useful functionality at the strategic 2-position. [source] | |||||||||||||