- Site-Selective Installation of N?-Modified Sidechains into Peptide and Protein Scaffolds via Visible-Light-Mediated Desulfurative C–C Bond Formation
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Post-translational modifications (PTMs) enhance the repertoire of protein function and mediate or influence the activity of many cellular processes. The preparation of site-specifically and homogeneously modified proteins, to apply as tools to understand the biological role of PTMs, is a challenging task. Herein, we describe a visible-light-mediated desulfurative C(sp3)–C(sp3) bond forming reaction that enables the site-selective installation of N?-modified sidechains into peptides and proteins of interest. Rapid, operationally simple, and tolerant to ambient atmosphere, we demonstrate the installation of a range of lysine (Lys) PTMs into model peptide systems and showcase the potential of this technology by site-selectively installing an N?Ac sidechain into recombinantly expressed ubiquitin (Ub).
- Griffiths, Rhys C.,Layfield, Robert,Long, Jed E.,Mitchell, Nicholas J.,Oldham, Neil J.,Scott, Daniel,Smith, Frances R.,Williams, Huw E. L.
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supporting information
(2021/12/08)
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- Micellar Catalysis for Sustainable Hydroformylation
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It is here reported a fully sustainable and generally applicable protocol for the regioselective hydroformylation of terminal alkenes, using cheap commercially available catalysts and ligands, in mild reaction conditions (70 °C, 9 bar, 40 min). The process can take advantages from both micellar catalysis and microwave irradiation to obtain the linear aldehydes as the major or sole regioisomers in good to high yields. The substrate scope is largely explored as well as the application of hydroformylation in tandem with intramolecular hemiacetalization thus demonstrating the compatibility with a broad variety of functional groups. The reaction is efficient even in large scale and the catalyst and micellar water phase can be reused at least 5 times without any impact in reaction yields. The efficiency and sustainability of this protocol is strictly related to the in situ transformation of the aldehyde into the corresponding Bertagnini's salt that precipitates in the reaction mixture avoiding organic solvent mediated purification steps to obtain the final aldehydes as pure compounds.
- Calamante, Massimo,Dei, Filippo,Maramai, Samuele,Migliorini, Francesca,Petricci, Elena
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p. 2794 - 2806
(2021/05/03)
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- A Next-Generation Air-Stable Palladium(I) Dimer Enables Olefin Migration and Selective C?C Coupling in Air
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We report a new air-stable PdI dimer, [Pd(μ-I)(PCy2tBu)]2, which triggers E-selective olefin migration to enamides and styrene derivatives in the presence of multiple functional groups and with complete tolerance of air. The same dimer also triggers extremely rapid C?C coupling (alkylation and arylation) at room temperature in a modular and triply selective fashion of aromatic C?Br, C?OTf/OFs, and C?Cl bonds in poly(pseudo)halogenated arenes, displaying superior activity over previous PdI dimer generations for substrates that bear substituents ortho to C?OTf.
- Kundu, Gourab,Rissanen, Kari,Schoenebeck, Franziska,Sperger, Theresa
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supporting information
p. 21930 - 21934
(2020/10/02)
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- An Unconventional Reaction of 2,2-Diazido Acylacetates with Amines
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We have discovered that 2,2-diazido acylacetates, a class of compounds with essentially unknown reactivity, can be coupled to amines through a new strategy that does not involve any reagents. 2,2-Diazido acetate is the unconventional leaving group under carbon–carbon bond cleavage. This reaction leads to the construction of amide bonds, tolerates various functionalities and is performed equally well in numerous solvents under experimentally simple conditions. We also demonstrate that the isolation of the 2,2-diazido acylacetate compounds can be circumvented: Acylacetates were easily fragmented when treated with (Bu4N)N3 and iodine in the presence of an amine at room temperature. By using this method, a broad range of acylacetates with various structural motifs were directly transformed into amides.
- H?ring, Andreas P.,Biallas, Phillip,Kirsch, Stefan F.
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supporting information
p. 1526 - 1539
(2017/04/01)
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- Transition metal-free intermolecular a-C-H amination of ethers at room temperature
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We describe a new method for the intermolecular amination of the α-C-H bonds of ethers. A hypervalent iodine reagent was used as oxidant to enable the amination of cyclic and acyclic alkyl ethers with a wide range of amides, imides, and amines. The amination occurred at room temperature and without a transition metal catalyst. The method could be used to synthesize the anti-cancer prodrug Tegafur and its analogues.
- Buslov, Ivan,Hu, Xile
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supporting information
p. 3325 - 3330
(2015/02/02)
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- Iodine(III)-promoted synthesis of oxazolines from N-allylamides
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PhI(OAc)2 (activated by BF3·OEt2) has been used to promote the oxidative cyclization of N-allylamides to give oxazolines. The reaction products are formed in high yield and, when a branched allylic amine is used, high diastereoselectivity. Initial mechanistic experiments suggest that the final C-O bond is formed from a reactive tight ion pair, rather than a neutral external nucleophile.
- Moon, Nicholas G.,Harned, Andrew M.
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supporting information
p. 2960 - 2963
(2013/06/27)
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- SYNTHESIS OF HYDROXYALKYL AMIDES FROM ESTERS
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Hydroxyamides are synthesized from esters. A process of making hydroxyalkyl amides comprises: reacting an ester with a hydroxyalkyl amine having the formula H2N—R3—OH wherein R3 is a substituted or unsubstituted C2 to C5 alkyl, in the presence of a catalyst in an anhydrous solution to form the hydroxyalkyl amides. Monomers suitable for formation of polymeric articles can utilize these hydroxyamides.
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Page/Page column 3
(2012/11/08)
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- Substrate-directable heck reactions with arenediazonium salts. The regio- and stereoselective arylation of allylamine derivatives and applications in the synthesis of naftifine and abamines
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The palladium-catalyzed, substrate-directable Heck-Matsuda reaction of allylamine derivatives with arenediazonium salts is reported. The reaction proceeds under mild conditions, with excellent regio- and stereochemical control as a function of coordinating groups present in the allylamine substrate. The distance between the olefin moiety and the car-bonylic system seems to play a key role regarding the regiocontrol. The method presents itself as robust, as simple to carry out, and with wide synthetic scope concerning the allylic substrates and the type of arenediazonium employed. The synthetic potential of the method is illustrated by the short total syntheses of the bioactive compounds naftifine, abamine, and abamine SG.
- Prediger, Patricia,Barbosa, Lais Ferreira,Genisson, Yves,Correia, Carlos Roque Duarte
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experimental part
p. 7737 - 7749
(2011/12/01)
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- Olefin cross-metathesis on proteins: Investigation of allylic chalcogen effects and guiding principles in metathesis partner selection
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Olefin metathesis has recently emerged as a viable reaction for chemical protein modification. The scope and limitations of olefin metathesis in bioconjugation, however, remain unclear. Herein we report an assessment of various factors that contribute to productive cross-metathesis on protein substrates. Sterics, substrate scope, and linker selection are all considered. It was discovered during this investigation that allyl chalcogenides generally enhance the rate of alkene metathesis reactions. Allyl selenides were found to be exceptionally reactive olefin metathesis substrates, enabling a broad range of protein modifications not previously possible. The principles considered in this report are important not only for expanding the repertoire of bioconjugation but also for the application of olefin metathesis in general synthetic endeavors.
- Lin, Yuya A.,Chalker, Justin M.,Davis, Benjamin G.
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supporting information; experimental part
p. 16805 - 16811
(2011/02/17)
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- An iron-catalysed synthesis of amides from nitriles and amines
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The cheap, commercially available iron complex, Fe(NO3)3·9H2O, has been used to catalyse the formation of amides by the addition of amines to nitriles.
- Allen, C. Liana,Lapkin, Alexei A.,Williams, Jonathan M.J.
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experimental part
p. 4262 - 4264
(2009/10/26)
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- Amidation through carbamates
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N-Alkyl carbamates of primary amines are easily converted into amides under treatment with Grignard reagents. Consequently, primary amines can be converted into amides in a one-pot reaction through carbamate protection and Grignard addition.
- Latorre, Antonio,Rodríguez, Santiago,Izquierdo, Javier,González, Florenci V.
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experimental part
p. 2653 - 2655
(2009/08/09)
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- Hydrolytic deallylation of N-allyl amides catalyzed by PdII complexes
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Hydrolytic deallylation of N-allyl amides to give amides and propanal can be achieved with PdII catalysts. The optimized catalyst consists of Pd(OCOCF3)2 and 1,3-bis(diphenylphosphanyl) propane (DPPP). Several kinds of open-chain N-allyl amides and N-allyl lactams undergo hydrolytic deallylation to give the corresponding amides and lactams in good to high yield. A mechanism which includes isomerization to enamides and subsequent hydrolysis is proposed. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Ohmura, Naoya,Nakamura, Asami,Hamasaki, Akiyuki,Tokunaga, Makoto
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supporting information; experimental part
p. 5042 - 5045
(2009/05/07)
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- Microwaves-assisted solvent-free synthesis of N-acetamides by amidation or aminolysis
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The preparation of acetamides directly from amines and an acetyl donor under microwaves without any catalyst is described. The inexpensive, solvent free, and fast reaction conditions are the important features of this procedure.
- Ferroud, Clotilde,Godart, Marie,Ung, Stéphane,Borderies, Hélène,Guy, Alain
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p. 3004 - 3008
(2008/09/20)
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- Tandem hydroformylation-hydrazone formation-Fischer indole synthesis: A novel approach to tryptamides
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A novel one-pot synthesis of indole systems via tandem hydroformylation-hydrazone formation-Fischer indolization starting from allylic amides and aryl hydrazines is described. This tandem procedure directly leads to biologically interesting tryptamides and analogues. The Royal Society of Chemistry 2005.
- Schmidt, Axel M.,Eilbracht, Peter
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p. 2333 - 2343
(2007/10/03)
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- Transamidation catalyzed by a recoverable and reusable polyDMAP-based hafnium chloride and montmorillonite KSF
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In this article, we described the use of an easily available polymer-based hafnium chloride and montmorillonite KSF catalyst (HfCl4/KSF- polyDMAP) in transamidation under relatively mild conditions. This metal catalyst can be easily recovered and reused in this reaction to give the corresponding amides in good yields. Copyright Taylor & Francis, Inc.
- Shi, Min,Cui, Shi-Cong
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p. 2847 - 2858
(2007/10/03)
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- Homolytic fragmentation of allyloxychlorocarbene
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(Chemical Equation Presented) The decomposition of allyloxychlorocarbene in hydrocarbon solvents leads via homolysis to allyl and COCl radicals, which recombine to 3-butenoyl chloride or (after scission of ?COCl to CO and ?Cl) to all
- Moss, Robert A.,Ma, Yan,Fu, Xiaolin,Sauers, Ronald R.
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p. 2055 - 2058
(2007/10/03)
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- Preparation of secondary and tertiary amides under neutral conditions by photochemical acylation of amines
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The smooth and neutral acylation of amines to form amides by photoactivation of N-acyl-5,7-dinitroindolines is described. An improved acylation of nitroindolines allows the convenient preparation of N-acylnitroindolines. This reaction makes possible the recycling of the nitroindoline released during the photoactivation.
- Helgen,Bochet
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p. 1968 - 1970
(2007/10/03)
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- Intermediates for the preparation of iodinated contrast agents
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5-Substituted isophthalic acid bis(allylamides) and bis(allylamide epoxides) in which said 5-substituent is -NO2, -NH2, -NHR1 or -NR1R2 where R1 and R2 are independently optionally substituted alkyl, alkenyl, acyl, aryl, aralkyl or alkaryl groups.
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- Synthesis of γ-amino- and δ-amino-functionalised ethers, amines, or silanes by hydroaminomethylation of heterofunctionalised allylic compounds
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Heterofunctionalised allylic ethers 1, silanes 5, and amines 9 are hydroformylated in the presence of primary or secondary amines 2 to form the corresponding γ-amino- and δ-amino-functionalised compounds. The rhodium(I)-catalysed reaction sequence proceeds by aldehyde formation and subsequent reductive amination to generate the corresponding functionalised secondary or tertiary amines. This selective one-pot hydroaminomethylation procedure establishes access to γ-amino- and δ-amino-functionalised ethers, amines or silanes with potential biological activity.
- Rische, Thorsten,Baerfacker, Lars,Eilbracht, Peter
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p. 653 - 660
(2007/10/03)
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- A metathetical cycloaddition-cycloreversion approach to the formation of furan scaffold libraries
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A general cycloaddition-cycloreversion metathesis procedure for the selective formation of a furan-based template-directed scaffold is described. In addition, features relative to library construction, such as the chemoselective nature of dipole formation, are discussed. Through the investigation of the temperature sensitive cleavage step, the furan synthesis was found to be accelerated by aqueous medium at physiological temperature leading to pure product from the solid-phase under biologically relevant conditions. The chemoselective nature of the rhodium(II) mediated cycloaddition allowed the selective formation of a key dipole intermediate, in the presence of a number of carbene-active functional groups, to facilitate the split-pool combinatorial synthesis of a small library of compounds. Copyright (C) 1998 Elsevier Science Ltd.
- Whitehouse, Darren L.,Nelson Jr., Kingsley H.,Savinov, Sergey N.,Loewe, Ralf S.,Austin, David J.
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p. 1273 - 1282
(2007/10/03)
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- An anomalous Dakin-West reaction of N-carbamate substituted prolines and trifluoroacetic anhydride
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A novel transformation of N-alkoxycarbonylprolines 1 to 4-trifluoroacetyl-2,3-dihydropyrroles 2 was efficiently realized by utilizing trifluoroacetic anhydride, in which probable intermediates were mesoionic 1,3-oxazolium-5-olates B.
- Kawase, Masami,Hirabayashi, Michitaka,Koiwai, Hiromi,Yamamoto, Katsumi,Miyamae, Hiroshi
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p. 641 - 642
(2007/10/03)
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- Organoselenium- and Proton-Mediated Cyclization Reactions of Allylic Amides and Thioamides. Syntheses of 2-Oxazolines and 2-Thiazolines
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A variety of allylic amides and thioamides were treated with phenylselenenyl bromide in chloroform to give, via 5-exo cyclization, 2-oxazolines and 2-thiazolines, respectively, carrying a (phenylselenenyl)methyl substituent in the 5-position.In some cases (N-crotyl- and N-cinnamylamides/thioamides), dihydro-1,3-oxazines/-thiazines were formed via 6-endo cyclization.The phenylselenenyl group of the cyclofunctionalization products was slowly eliminated by treatment with m-chloroperbenzoic acid to introduce unsaturation in the resulting oxazoline/thiazoline.Reductive removal of the phenylselenenyl group was effected by treatment with triphenyltin hydride.This reaction was sometimes accompanied by a rearrangement of the heterocyclic ring.Proton-induced cyclizations of allylic thioamides to give 2-thiazolines was slowly but efficiently effected in boiling toluene containing a catalytic amount of p-toluenesulfonic acid.
- Engman, Lars
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p. 3425 - 3430
(2007/10/02)
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- Facile Catalytic Conversion of Carboxylic Acids into Thiocarboxylic S-Acids by the Ph3SbO/P4S10 System
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Thiocarboxylic S-acids 2 are readily prepared by direct sulfuration of the corresponding carboxylic acids 1 catalyzed by Ph3SbO/P4S10 under mild conditions.
- Nomura, Ryoki,Miyazaki, Shin-Ichiro,Nakano, Takahiro,Matsuda, Haruo
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p. 2081 - 2082
(2007/10/02)
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- Substituted 1,3-diphenyl pyrrolidones and their use as herbicides
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Substituted 1,3-diphenyl pyrrolidones of the formula STR1 in which R1 and R3 are halogen, trifluoromethyl, cyano, alkyl or alkoxy, R2 is H or halogen, and R4 is alkyl or haloalkyl, are useful as herbicidal agents.
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- New Routes to Heterocycles via Sulphenylation of Unsaturated Amides
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The reaction of manganese(III) acetate with diphenyl disulphide in dichloromethane-trifluoroacetic acid in the presence of N-allylacetamide, followed by hydrolysis, affords a vicinal hydroxy sulphide.Similarly, addition to N-allyltrifluoroacetamide affords hydroxy sulphide adducts, but with different regioselectivity.N-Allylbenzamide and other unsaturated benzamides under similar conditions give cyclic products, 4,5-dihydro-1,3-oxazoles.Homoallylic amides give 5,6-dihydro-4H-1,3-oxazines.Amides derived from pent-4-enylamine give substituted pyrrolidines by cyclisation through nitrogen, but N-hex-5-enylbenzamide gives only an acyclic adduct.Unsaturated carboxylic acids and unsaturated carboxamides are transformed in good yield into lactones under similar conditions.
- Samii, Zakaria K. M. Abd El,Ashmawy, Mohamed I. Al,Mellor, John M.
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p. 2517 - 2522
(2007/10/02)
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- Photochemistry of Epoxynaphthoquinones. 8. Endo-Stereoselective Photocycloaddition of 2,3-Epoxy-2,3-dihydro-2,3-dimethyl-1,4-naphthoquinone to Olefins Containing Amide Group
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Irradiation of a benzene solution of 2,3-epoxy-2,3-dihydro-2,3-dimethyl-1,4-naphthoquinone with olefins containing amide group, i.e., N-substituted acrylamides and N-allylcarboxamides predominantly gave the endo-cycloadducts.Upon further irradiation, the cycloadducts underwent photorearrangement to give spirophthalides and alkylidenephthalides.
- Maruyama, Kazuhiro,Osuka, Atsuhiro,Nakagawa, Katsuhiko
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p. 1021 - 1026
(2007/10/02)
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- REGIOSELECIVE HYDROXYSULPHENYLATION OF DERIVATIVES OF ALLYLIC ALCOHOLS AND AMINES
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Reaction of manganic acetate with diphenyldisulphide in dichloromethane-trifluoroacetic acid in the presence of allylic esters or amides of allylamine gives trifluoroacetoxysulphides and hence by ready hydrolysis vicinal hydroxysulphides.The regiochemical outcome can be controlled by selection of either an acetyl- or trifluoroacetyl derivative.
- Samii, Zakaria K M Abd El,Ashmawy, Mohamed I Al,Mellor, John M
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p. 5289 - 5292
(2007/10/02)
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- Direct N-Allylation of Amides with 2-Allylisourea Catalyzed by Palladium(0)
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Direct N-allylation of amides catalyzed by palladium(0) complexes took place under neutral conditions by the use of 2-allylisourea as the allylating agent.
- Inoue, Yoshio,Taguchi, Masaaki,Hashimoto, Harukichi
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p. 2721 - 2722
(2007/10/02)
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- N-ALKYLATION OF ACETAMIDE
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The possibility of the N-alkylation of acetamides by alkyl halides in the presence of potassium fluoride was demonstrated.The yield of the product increases with the addition of catalytic amounts of a quartenary ammonium salt.N-Alkylation also take place in the presence of powdered alkali in aprotic solvents.The alkylation of acetamide was also realized with ethylene chlorohydrin in the presence of an equimolar amount of pyridine.
- Torosyan, G. O.,Tagmazyan, N. K.,Babayan, A. T.
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p. 456 - 459
(2007/10/02)
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- New Allylation Reaction using Allylmetal (Group IVb) Compounds: Synthesis of N-Allylamides
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Reaction of allylsilanes 1a and 1d or allylstannane 1b with thallium(III) salts in nitriles such as acetonitrile, acrylonitrile, propionitrile, and benzonitrile afforded the corresponding N-allylamides.Thus, umpolung of reactivity of allylsilane and allylstannane has been established.Keywords-umpolung of reactivity; allylsilane; allylstannane; N-allylamide; thallium(III) salt; nitrile
- Ochiai, Masahito,Tada, Shin-Ichi,Arimoto, Masao,Fujita, Eiichi
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p. 2836 - 2839
(2007/10/02)
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- Isomerization of N-Allylamides and -imides to Aliphatic Enamides by Iron, Rhodium, and Ruthenium Complexes
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Substituted aliphatic N-propenylamides and -imides are readily sythesized from N-allylamides by double bond migration induced by rhodium or ruthenium hydrides.N-Propenylimides can be prepared from allylimides only in the presence of iron pentacarbonyl.
- Stille, J. K.,Becker Y.
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p. 2139 - 2145
(2007/10/02)
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