- Catalytic SNAr Hydroxylation and Alkoxylation of Aryl Fluorides
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Nucleophilic aromatic substitution (SNAr) is a powerful strategy for incorporating a heteroatom into an aromatic ring by displacement of a leaving group with a nucleophile, but this method is limited to electron-deficient arenes. We have now established a reliable method for accessing phenols and phenyl alkyl ethers via catalytic SNAr reactions. The method is applicable to a broad array of electron-rich and neutral aryl fluorides, which are inert under classical SNAr conditions. Although the mechanism of SNAr reactions involving metal arene complexes is hypothesized to involve a stepwise pathway (addition followed by elimination), experimental data that support this hypothesis is still under exploration. Mechanistic studies and DFT calculations suggest either a stepwise or stepwise-like energy profile. Notably, we isolated a rhodium η5-cyclohexadienyl complex intermediate with an sp3-hybridized carbon bearing both a nucleophile and a leaving group.
- Kang, Qi-Kai,Li, Ke,Li, Yuntong,Lin, Yunzhi,Shi, Hang,Xu, Lun
-
supporting information
p. 20391 - 20399
(2021/08/13)
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- Reductive Amidation without an External Hydrogen Source Using Rhodium on Carbon Matrix as a Catalyst
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An efficient method for preparation of secondary amides from primary amides and aldehydes using rhodium on carbon matrix as catalyst was developed. The method does not require any external hydrogen source and carbon monoxide is used as a reducing agent. The most active rhodium catalysts were characterized by BET, TEM and XPS techniques. Unexpectedly, it was found that heterogeneous rhodium on carbon matrix works as precatalyst for homogenous active species due to leaching of rhodium to the solution. Various secondary amides were synthesized and checked for antifungal activity. 4-Methoxy-N-(4-methoxybenzyl)benzamide demonstrated promising activity against Rhizoctonia Solani.
- Tsygankov, Alexey A.,Makarova, Maria,Afanasyev, Oleg I.,Kashin, Alexey S.,Naumkin, Alexander V.,Loginov, Dmitry A.,Chusov, Denis
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p. 112 - 117
(2019/11/28)
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- Diversity Oriented Clicking (DOC): Divergent Synthesis of SuFExable Pharmacophores from 2-Substituted-Alkynyl-1-Sulfonyl Fluoride (SASF) Hubs
-
Diversity Oriented Clicking (DOC) is a unified click-approach for the modular synthesis of lead-like structures through application of the wide family of click transformations. DOC evolved from the concept of achieving “diversity with ease”, by combining classic C?C π-bond click chemistry with recent developments in connective SuFEx-technologies. We showcase 2-Substituted-Alkynyl-1-Sulfonyl Fluorides (SASFs) as a new class of connective hub in concert with a diverse selection of click-cycloaddition processes. Through the selective DOC of SASFs with a range of dipoles and cyclic dienes, we report a diverse click-library of 173 unique functional molecules in minimal synthetic steps. The SuFExable library comprises 10 discrete heterocyclic core structures derived from 1,3- and 1,5-dipoles; while reaction with cyclic dienes yields several three-dimensional bicyclic Diels–Alder adducts. Growing the library to 278 discrete compounds through late-stage modification was made possible through SuFEx click derivatization of the pendant sulfonyl fluoride group in 96 well-plates—demonstrating the versatility of the DOC approach for the rapid synthesis of diverse functional structures. Screening for function against MRSA (USA300) revealed several lead hits with improved activity over methicillin.
- Barrow, Andrew S.,Cheng, Yunfei,Gialelis, Timothy L.,Giel, Marie-Claire,Kitamura, Seiya,Li, Gencheng,Moses, John E.,Ottonello, Alessandra,Sharpless, K. Barry,Smedley, Christopher J.,Wolan, Dennis W.
-
supporting information
p. 12460 - 12469
(2020/06/10)
-
- Fe3O4@PEG core/shell nanoparticles as magnetic nanocatalyst for acetylation of amines and alcohols using ultrasound irradiations under solvent-free conditions
-
Abstract: Ultrasound irradiation was used to prepare one-pot Fe3O4@PEG core/shell nanostructure for the first time. The morphology, structure, and physicochemical properties were specified by different analytical techniques including field emission scanning electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray powder diffraction, and vibrating sample magnetometer. For acetylation of phenols, alcohols, and amines, the synthesized Fe3O4@PEG core/shell nanoparticles were used as an efficient heterogeneous and green catalyst with acetic anhydride under sonication applying mild reaction conditions. Different electron-withdrawing and electron-donating substrates indicate a prominent yield of desired products with the merit of reusability of Fe3O4@PEG nanocatalyst and magnetic separation. Graphical Abstract: [Figure not available: see fulltext.].
- Veisi, Hojat,Nikseresht, Ahmad,Rostami, Afsaneh,Hemmati, Saba
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p. 507 - 520
(2018/10/24)
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- Graphene Oxide: A Metal-Free Carbocatalyst for the Synthesis of Diverse Amides under Solvent-Free Conditions
-
An environmentally friendly, inexpensive, carbocatalyst, graphene oxide (GO) promoted efficient, metal-free transamidation of various carboxamides with aliphatic, cyclic, and aromatic amines is demonstrated. The protocol is equally applicable to phthalimide, urea, and thioamide determining its adaptability. The oxygenated functionalities such as carbonyl (?C=O), epoxy (?O?), carboxyl (?COOH) and hydroxyl (?OH), present on graphene oxide surface impart acidic properties to the catalyst. The graphene oxide being heterogeneous in nature, work efficiently under solvent-free reaction conditions providing desired products in good to excellent yields. The one-pot synthesis of 2,3-Dihydro-5H-benzo[b]-1,4-thiazepin-4-one moiety by GO catalyzed Aza Michael addition followed by intramolecular transamidation is also described. A plausible reaction mechanistic pathway involving H-bonding is discussed. The graphene oxide can be recycled and reused up to five cycles without much loss in catalytic activity. (Figure presented.).
- Patel, Khushbu P.,Gayakwad, Eknath M.,Patil, Vilas V.,Shankarling, Ganapati S.
-
supporting information
p. 2107 - 2116
(2019/03/26)
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- Ruthenium-Catalyzed Reductive Amidation without an External Hydrogen Source
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A catalytic reaction between aldehydes and primary amides that leads to N-alkylated amides was investigated. The developed protocol employs carbon monoxide as a deoxygenative agent and, therefore, avoids the use of an external hydrogen source. Cyclopentad
- Yagafarov, Niyaz Z.,Muratov, Karim M.,Biriukov, Klim,Usanov, Dmitry L.,Chusova, Olga,Perekalin, Dmitry S.,Chusov, Denis
-
supporting information
p. 557 - 563
(2018/02/09)
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- Preparation of Polydopamine Sulfamic Acid-Functionalized Silica Gel as Heterogeneous and Recyclable Nanocatalyst for Acetylation of Alcohols and Amines Under Solvent-Free Conditions
-
To fabricate SiO2/PDA–SO3H nanocatalyst, a suitable method is designed for the loading of sulfonic acid groups on the surface of polydopamine (PDA)-encapsulated SiO2 nanoparticles. To bridge the gap between heterogeneous and homogeneous catalysis, surface functionalization of silica gel is an elegant procedure. The morphology, structure, and physicochemical features were specified using different analytical techniques including field emission scanning electron microscopy (FESEM), Fourier transformed infrared spectroscopy (FT-IR), high resolution-transmission electron microscopy (HR-TEM), energy dispersive X-ray spectroscopy (EDS), wavelength-dispersive X-ray spectroscopy (WDX), X-ray photoelectron spectroscopy (XPS), and back titration. The SiO2/PDA–SO3H nanoparticles are efficient nanocatalysts for the acetylation of many alcohols, phenols, and amines with acetic anhydride under solvent-free conditions in good to excellent yields. Moreover, the reuse and recovery of the catalyst was shown seven times without detectible loss in activity. Graphical Abstract: [Figure not available: see fulltext.]
- Veisi, Hojat,Vafajoo, Saba,Bahrami, Kiumars,Mozafari, Bita
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p. 2734 - 2745
(2018/07/30)
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- Manganese-Catalyzed Direct Conversion of Ester to Amide with Liberation of H2
-
A simple and efficient Mn-catalyzed acylation of amines is achieved using both acyl and alkoxy functions of unactivated esters with the liberation of molecular hydrogen as a sole byproduct. The present protocol provides an atom-economical and sustainable route for the synthesis of amides from esters by employing an earth-abundant manganese salt and inexpensive phosphine-free tridentate ligand.
- Mondal, Akash,Subaramanian, Murugan,Nandakumar, Avanashiappan,Balaraman, Ekambaram
-
supporting information
p. 3381 - 3384
(2018/06/11)
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- Nickel-Catalyzed Phosphine Free Direct N-Alkylation of Amides with Alcohols
-
Herein, we developed an operational simple, practical, and selective Ni-catalyzed synthesis of secondary amides. Application of renewable alcohols, earth-abundant and nonprecious nickel catalyst facilitates the transformations, releasing water as byproduct. The catalytic system is tolerant to a variety of functional groups including nitrile, allylic ether, and alkene and could be extended to the synthesis of bis-amide, antiemetic drug Tigan, and dopamine D2 receptor antagonist Itopride. Preliminary mechanistic studies revealed the participation of a benzylic C-H bond in the rate-determining step.
- Das, Jagadish,Banerjee, Debasis
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p. 3378 - 3384
(2018/03/26)
-
- Photocatalyzed synthesis of isochromanones and isobenzofuranones under batch and flow conditions
-
Photocatalyzed reactions of 2-(alkoxycarbonyl)benzenediazonium tetrafluoroborates with various alkenes afforded isochromanones in good yields, according to a mechanism that was investigated. The advantage of using highly soluble esters rather than carboxylic acids as starting compounds became evident when the reactions were performed under flow conditions. On the other hand, when 2-vinylbenzoic acid derivatives were employed as reagents, isobenzofuranones were obtained together with unprecedented benzo[e][1,3]oxazepin-1(5H)-ones, with the latter derived from incorporation of the solvent (acetonitrile).
- Anselmo, Manuel,Moni, Lisa,Ismail, Hossny,Comoretto, Davide,Riva, Renata,Basso, Andrea
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supporting information
p. 1456 - 1462
(2017/08/02)
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- Dichotomy of Atom-Economical Hydrogen-Free Reductive Amidation vs Exhaustive Reductive Amination
-
Rh-catalyzed one-step reductive amidation of aldehydes has been developed. The protocol does not require an external hydrogen source and employs carbon monoxide as a deoxygenative agent. The direction of the reaction can be altered simply by changing the solvent: reaction in THF leads to amides, whereas methanol favors formation of tertiary amines.
- Kolesnikov, Pavel N.,Usanov, Dmitry L.,Muratov, Karim M.,Chusov, Denis
-
supporting information
p. 5657 - 5660
(2017/10/25)
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- Transition-Metal- and Halogen-Free Oxidation of Benzylic sp 3 C-H Bonds to Carbonyl Groups Using Potassium Persulfate
-
Aryl carbonyl compounds including acetophenones, benzophenones, imides, and benzoic acids are prepared from benzyl substrates using potassium persulfate as oxidant with catalytic pyridine in acetonitrile under mild conditions. Neither transition metals nor halogens are involved in the reactions.
- Hu, Yixin,Zhou, Lihong,Lu, Wenjun
-
supporting information
p. 4007 - 4016
(2017/08/29)
-
- 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.
-
supporting information
p. 1526 - 1539
(2017/04/01)
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- Transamidation catalysed by a magnetically separable Fe3O4 nano catalyst under solvent-free conditions
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An environmentally benign protocol for transamidation of carboxamides with different amines under solvent free conditions using magnetically separable nano Fe3O4 as a heterogeneous catalyst is developed. The series of aryl and alkyl amines with long chain alkyl substituents have been selectively converted into transamide products. The current protocol offers a diverse substrate scope with good yield of the product. The Fe3O4 nano catalyst has also been used for formylation of amines via transamidation of dimethyl formamide. Efficient transamidation, ease of work up, simple separation and reusability of the catalyst for up to six runs are the important highlights of this process.
- Thale, Pranila B.,Borase, Pravin N.,Shankarling, Ganapati S.
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p. 52724 - 52728
(2016/06/14)
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- Aqueous MW eco-friendly protocol for amino group protection
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In this paper a new catalyst-free and on-water method for protection of amines and amino acids with di-tert-butyl dicarbonate, 9-fluorenylmethoxycarbonyl chloride, acetyl chloride and tosyl chloride is presented. The protection can be realized in a few minutes under microwave-assistance. The reaction proved to be chemoselective in presence of ambident nucleophiles and water solution of di-tert-butyl carboxylic acid or chloride acid are the only wastes produced.
- Nardi,Cano, N. Herrera,Costanzo,Oliverio,Sindona,Procopio
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p. 18751 - 18760
(2015/06/15)
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- An attractive route to transamidation catalysis: Facile synthesis of new o-aryloxide-N-heterocyclic carbene ruthenium(II) complexes containing trans triphenylphosphine donors
-
Well-defined robust ruthenium(II) complexes 3a-d bearing o-aryloxide-N-heterocyclic carbene ligands with different wingtip substituents (3a (R = Me), 3b (R = Ph), 3c (R = iPr) and 3d (R = Mes)) in the imidazole ring were synthesized in good yields by the reaction of imidazolium proligands with metal precursor [RuHCl(CO)(PPh3)3] by transmetallation from the corresponding silver carbene complexes. All the Ru(II)-NHC complexes have been characterized by elemental analyses, spectroscopic methods as well as ESI mass spectrometry. The molecular structure of the complex 3a was identified by means of single-crystal X-ray diffraction analysis, which revealed that the complexes possess a distorted octahedral geometry. In order to explore the catalytic potential of the synthesized complexes, all the four [Ru-NHC] complexes [3a-d] were tested as catalysts for transamidation of carboxamides with amines. Notably, the complex 3a was found to be very efficient and versatile catalyst toward transamidation of a wide range of amides with amines.
- Nirmala, Muthukumaran,Prakash, Govindan,Viswanathamurthi, Periasamy,Malecki, Jan Grzegorz
-
-
- H-β-zeolite catalyzed transamidation of carboxamides, phthalimide, formamides and thioamides with amines under neat conditions
-
Efficient transamidation of unactivated carboxamides, phthalimides, formamides and thioamides with amines under solvent-free conditions using H-β-zeolite as a green and recyclable heterogeneous catalyst is described. Easy work up, high purity of the products, recyclability and environmentally-friendly nature of the catalyst are the attractive features of the present methodology. This is the first report for the transamidation of thioamides under heterogeneous conditions.
- Rao, Sadu Nageswara,Chandra Mohan, Darapaneni,Adimurthy, Subbarayappa
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p. 95313 - 95317
(2015/11/24)
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- Designing of thermally stable amide functionalized benzimidazolium perchlorate ionic liquid for transamidation of primary carboxamides
-
In the present work, we have designed and synthesized a thermally stable catalyst based on functionalized benzimidazolium perchlorate ionic liquid and tested its efficacy towards metal free and solvent free transamidation of amides and amines. The ionic liquid comprising the perchlorate ion has shown remarkably better activity than those which contain other anions and accordingly a plausible mechanism for the catalytic activity is arrived. The developed catalytic system has shown excellent activity towards the transamidation of alicyclic and aromatic amines with acetamide, benzamide and p-nitrobenzamide under mild conditions. Furthermore, the transamidation of nicotinamide with benzylamine in presence of the ionic liquid catalyst was found to occur with very good yields and thus provides a facile route for the synthesis of pharmaceutically significant compounds. The catalyst has exhibited very good thermal stability upto 203 °C and very good recyclability upto 5 runs without significant loss in its activity.
- Muskawar, Prashant Narayan,Thenmozhi,Bhagat, Pundlik Rambhau
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p. 158 - 167
(2015/09/28)
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- Hydrogen bond organocatalysis of benzotriazole in transamidation of carboxamides with amines
-
A new method of transamidation of carboxamides with amines catalyzed by benzotriazole has been developed.
- Nguyen, Thanh Binh,Ermolenko, Ludmila,Dau, Marie-Elise Tran Huu,Al-Mourabit, Ali
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p. 403 - 416
(2014/01/17)
-
- Tandem synthesis of amides and secondary amines from esters with primary amines under solvent-free conditions
-
An iridium(III)-catalyzed tandem synthesis of amides and amines from esters under solvent-free conditions is described. A commercially available iridium(III) complex, [Cp*IrCl2]2, with sodium acetate showed the best activity for the synthesis of amides and secondary amines. The amide was formed by ester-amide exchange which generates an alcohol in situ which is subsequently transformed to a secondary amine via hydrogen autotransfer. This synthetic protocol with high atom economy generates water as the sole by-product and can afford amides and amines from various esters in a one-pot reaction, expanding the synthetic versatility of ester transformations.
- Lee, Jeongbin,Muthaiah, Senthilkumar,Hong, Soon Hyeok
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p. 2653 - 2660
(2014/09/17)
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- L-Proline: An efficient catalyst for transamidation of carboxamides with amines
-
In the presence of a catalytic amount of l-proline (10 mol %), transamidations of carboxamides with amines were achieved under solvent-free conditions. The transamidation process is compatible with a wide range of amines.
- Rao, Sadu Nageswara,Mohan, Darapaneni Chandra,Adimurthy, Subbarayappa
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supporting information
p. 1496 - 1499
(2013/06/27)
-
- A novel and simple transamidation of carboxamides in 1,4-dioxane without a catalyst
-
An easy acylation and formylation of amines has been achieved via transamidation using 1,4-dioxane. The investigation works efficiently without an added catalyst and completes within short time under microwave irradiation.
- Vanjari, Rajeshwer,Allam, Bharat Kumar,Singh, Krishna Nand
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p. 2553 - 2555
(2013/06/05)
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- Application of SiO2-Pr-SO3H as an efficient catalyst in the Ritter reaction
-
Sulfonic-acid-functionalized silica was applied as an efficient heterogeneous acid catalyst in the Ritter reaction to prepare amides by reaction of various benzylic, allylic, and tertiary alcohols with various nitriles in good to excellent yields under solvent-free conditions. The simplicity of the reaction, recovery of catalyst without loss of reactivity, high yield of products, and short reaction time represent improvements over many existing methods.
- Mohammadi Ziarani, Ghodsi,Badiei, Alireza,Dashtianeh, Zeinab,Gholamzadeh, Parisa,Mohtasham, Nina Hosseini
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p. 3157 - 3163
(2013/09/23)
-
- One-pot stibine modified Co2(CO)8 catalyzed reductive N-alkylation of primary amides with carbonyl compounds
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A one-pot stibine modified Co2(CO)8 homogeneous catalytic reductive N-alkylation of primary amides using aldehydes/ketones as alkylating agents, is reported. Good to excellent yields of a wide range of secondary amides are obtained (up to 97%) under relative mild conditions.
- Rubio-Pérez, Laura,Sharma, Pankaj,Pérez-Flores, F. Javier,Velasco, Luis,Arias, J. Luis.,Cabrera, Armando
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experimental part
p. 2342 - 2348
(2012/04/10)
-
- Pentafluorophenylammonium triflate as a mild and new organocatalyst for acylation of alcohols, phenols, and amines under solvent-free condition
-
A simple, inexpensive, environmentally friendly and efficient route for the acylation of a number of alcohols, phenols and amines using pentafluorophenylammonium triflate (PFPAT) as a catalyst is described. PFPAT organocatalyst is air-stable, cost-effective, easy to handle, and easily removed from the reaction mixtures.
- Khaksar, Samad,Zakeri, Hasan
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p. 576 - 579,4
(2020/08/31)
-
- Transamidation of primary amides with amines catalyzed by zirconocene dichloride
-
Zirconocene dichloride (Cp2ZrCl2) has been shown to be an effective catalyst for the transamidation of primary amides with amines in cyclohexane at 80°C in 5-24 hours. For favourable substrates, the reaction can be performed at temperatures as low as 30°C.
- Atkinson, Benjamin N.,Chhatwal, A. Rosie,Lomax, Helen V.,Walton, James W.,Williams, Jonathan M. J.
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supporting information
p. 11626 - 11628,3
(2012/12/12)
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- Transamidation of primary amides with amines catalyzed by zirconocene dichloride
-
Zirconocene dichloride (Cp2ZrCl2) has been shown to be an effective catalyst for the transamidation of primary amides with amines in cyclohexane at 80°C in 5-24 hours. For favourable substrates, the reaction can be performed at temperatures as low as 30°C.
- Atkinson, Benjamin N.,Chhatwal, A. Rosie,Lomax, Helen V.,Walton, James W.,Williams, Jonathan M. J.
-
supporting information
p. 11626 - 11628
(2013/01/15)
-
- Poly-(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide) and N,N,N′,N′- tetrabromobenzene-1,3-disulfonamide as highly efficient catalysts, and (AC2O/SIO2) as a heterogeneous system for the acetylation of alcohols, amines, and thiols under microwave irradiation
-
Chemical Equation Presented Poly-(N,N′-dibromo-N-ethyl-benzene-1,3- disulfonamide) (PBBS) and N,N,N′,N′-tetrabromobenzene-1,3- disulfonamide (TBBDA) are good activators and catalytic reagents for the acetylation of alcohols, amines, and thiols. The presented method has the advantages of mild conditions, chemoselectivity, and good to high yields, and uses noncorrosive, inexpensive, recyclable, and environmentally friendly catalysts. We have also demonstrated that combining SiO2 with microwave energy provides an efficient, fast, convenient, and easy workup procedure for the synthesis of mono- and disubstituted acetates, acetamides, and thioacetamides. Copyright Taylor & Francis Group, LLC.
- Veisi, Hojat,Ghorbani-Vaghei, Ramin,Eskandari, Hosna,Hemmati, Saba,Rezaei, Ardashir,Hajinazari, Somaye,Far, Mohammad Raoof Heidari,Entezari, Azam
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experimental part
p. 213 - 219
(2011/04/24)
-
- Dynamic path bifurcation in the Beckmann reaction: Support from kinetic analyses
-
The reactions of oximes to amides, known as the Beckmann rearrangement, may undergo fragmentation to form carbocations + nitriles when the migrating groups have reasonable stability as cations. The reactions of oxime sulfonates of 1-substituted-phenyl-2-propanone derivatives (7-X) and related substrates (8-X, 9a-X) in aqueous CH3CN gave both rearrangement products (amides) and fragmentation products (alcohols), the ratio of which depends on the system; the reactions of 7-X gave amides predominantly, whereas 9a-X yielded alcohols as the major product. The logk-logk plots between the systems gave excellent linear correlations with slopes of near unity. The results support the occurrence of path bifurcation after the rate-determining TS of the Beckmann rearrangement/fragmentation reaction, which has previously been proposed on the basis of molecular dynamics simulations. It was concluded that path-bifurcation phenomenon could be more common than thought and that a reactivity-selectivity argument based on the traditional TS theory may not always be applicable even to a well-known textbook organic reaction.
- Yamamoto, Yutaro,Hasegawa, Hiroto,Yamataka, Hiroshi
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p. 4652 - 4660
(2011/07/29)
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- Metal acetate/metal oxide in acetic acid: An efficient reagent for the chemoselective N-acetylation of amines under green conditions
-
The use of catalytic amount of metal acetate or metal oxide in acetic acid is a new and highly efficient acetylating system for chemoselective N-acetylation of primary and secondary amines in excellent yields under reflux condition. No other solvent is required. The noted features of this method include mild reaction conditions, use of innocuous reagents, excellent yields, convenient work-up, and reuse of catalyst.
- Brahmachari, Goutam,Laskar, Sujay,Sarkar, Sajal
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experimental part
p. 288 - 295
(2010/10/18)
-
- Silica-bonded N-propyl sulfamic acid as an efficient catalyst for the formylation and acetylation of alcohols and amines under heterogeneous conditions
-
A simple and efficient procedure for the preparation of silica-bonded N-propyl sulfamic acid (SBNPSA) by the reaction of 3-aminopropylsilica (1) and chlorosulfonic acid in chloroform is described. This solid acid is employed as a new catalyst for the formylation of alcohols and amines with ethyl formate under mild and heterogeneous conditions at room temperature with good to excellent yields. Also, SBNPSA catalyzed acetylation of various alcohols and amines with acetic anhydride at room temperature.
- Niknam, Khodabakhsh,Saberi, Dariush
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experimental part
p. 5210 - 5214
(2009/12/06)
-
- o-Benzenedisulfonimide as a reusable Bronsted acid catalyst for Ritter-type reactions
-
Reactions between various benzyl alcohols or tert-butyl alcohol and nitriles were carried out in the presence of catalytic amounts (usually 10-20 mol-%) of o-benzenedisulfonimide as a Bronsted acid catalyst; the reaction conditions were mild and the yields of amides were good. The catalyst was easily recovered and purified, ready to be used in further reactions, with economic and ecological advantages. Wiley-VCH Verlag GmbH & Co. KGaA, 2009.
- Barbero, Margherita,Bazzi, Stefano,Cadamuro, Silvano,Dughera, Stefano
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experimental part
p. 430 - 436
(2009/07/19)
-
- Pyrano-[2,3b]-pyridines as potassium channel antagonists
-
The design and synthesis of a series of highly functionalized pyrano-[2,3b]-pyridines is described. These compounds were assayed for their ability to block the IKur channel encoded by the gene hKV1.5 in patch-clamped L-929 cells. Six of the compounds in this series showed sub-micromolar activity, the most potent being 4-(4-ethyl-benzenesulfonylamino)-3-hydroxy-2,2-dimethyl-3,4-dihydro-2H-pyrano[2,3b]-pyridine-6-carboxylic acid ethyl-phenyl-amide with an IC50 of 378 nM.
- Finlay, Heather J.,Lloyd, John,Nyman, Michael,Conder, Mary Lee,West, Tonya,Levesque, Paul,Atwal, Karnail
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p. 2714 - 2718
(2008/12/21)
-
- Catalytic metathesis of simple secondary amides
-
(Chemical Equation Presented) Trading places: The metathesis of secondary amides through a transacylation mechanism has been achieved by employing catalytic quantities of an organic imide and a Bronsted base (see scheme). Equilibrium-controlled exchange between various amide pairs is demonstrated for substrates bearing N-alkyl and N-aryl substituents.
- Bell, Christen M.,Kissounko, Denis A.,Gellman, Samuel H.,Stahl, Shannon S.
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p. 761 - 763
(2007/10/03)
-
- Benzyl amide-ketoacid inhibitors of HIV-integrase
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Integrase is one of three enzymes expressed by HIV and represents a validated target for therapy. Previous reports have demonstrated that the diketoacid-based chemotype is a useful starting point for the design of inhibitors of this enzyme. In this study, one of the ketone groups is replaced by a benzylamide resulting in a new potent chemotype. A preliminary SAR study is carried out to investigate the substitution requirements on the phenyl ring and methylene group of the benzylamide.
- Walker, Michael A.,Johnson, Timothy,Naidu, B. Narasimhulu,Banville, Jacques,Remillard, Roger,Plamondon, Serge,Martel, Alain,Li, Chen,Torri, Albert,Samanta, Himadri,Lin, Zeyu,Dicker, Ira,Krystal, Mark,Meanwell, Nicholas A.
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p. 4886 - 4890
(2008/02/13)
-
- (P2O5/SiO2): a useful heterogeneous alternative for the Ritter reaction
-
Tertiary alcohols as well as primary and secondary benzylic alcohols react efficiently with nitriles to give the corresponding amides in good to excellent yields in the presence of P2O5/SiO2 (60% w/w).
- Tamaddon, Fatemeh,Khoobi, Mehdi,Keshavarz, Elham
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p. 3643 - 3646
(2008/02/03)
-
- Transamidation catalyzed by a recoverable and reusable polyDMAP-based hafnium chloride and montmorillonite KSF
-
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)
-
- Mechanistic investigations on the reaction between amines or amides and an alkylperoxy-λ3-iodane
-
A mechanism involving the intermediate formation of an amine radical cation by single-electron transfer is proposed for the oxidation of secondary amines with alkylperoxy-λ3-iodane. On the other hand, the oxidation of acetamides probably proceeds by a radical process, which involves the direct hydrogen abstraction of the methylene group α to the nitrogen atom.
- Sueda, Takuya,Kajishima, Daisuke,Goto, Satoru
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p. 3307 - 3310
(2007/10/03)
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- TiO2-photocatalyzed reactions of some benzylic donors
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TiO2-photocatalyzed oxidation of toluene (1a), benzyltrimethylsilane (1b), and 4-methoxybenzyltrimethylsilane (1c) has been carried out in acetonitrile under oxygen, under nitrogen, and in the presence of electrophilic alkenes under various conditions (using Ag2SO 4 as electron acceptor, adding 2.5% H2O, changing solvent to CH2Cl2). Benzyl radicals, formed via electron transfer and fragmentation, are trapped. A good material balance is often obtained. The overall efficiency of the process depends on the donor Eox, on the rate of fragmentation of the radical cation, and on the acceptor present (Ag+ is an efficient oxidant, an electrophilic alkene a poor one, O2 is intermediate). With ring-unsubstituted benzyl derivatives 1a and 1b, oxidative fragmentation occurs mainly close to the catalyst surface. The benzyl radicals form at a high local concentration and give benzaldehyde under O2, bibenzyl under N2 and dibenzylated derivatives by attack on the alkenes (acrylonitrile, fumaronitrile, maleic acid). In this case, using CH2Cl2-O2 enhances the yield of benzaldehyde. With methoxylated 1c, however, the radical cation migrates into the solution before fragmentation and, therefore, the free benzyl radical is formed. This radical in part is oxidized to the cation, giving a considerable amount of benzylacetamide (or of the alcohol with water), and in part is trapped by the alkenes. The last reaction is less efficient in this case and yields monobenzyl derivatives.
- Cermenati, Laura,Fagnoni, Maurizio,Albini, Angelo
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p. 560 - 566
(2007/10/03)
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- Silica gel supported ferric perchlorate: A new and efficient reagent for one pot synthesis of amides from benzylic alcohols
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Benzylic alcohols react efficiently with nitriles in the presence of silica gel supported ferric perchlorate to produce amides in high yields.
- Salehi, Peyman,Motlagh, Aghamorad Rostamian
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p. 671 - 675
(2007/10/03)
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- A novel deprotection/functionalisation sequence using 2,4- dinitrobenzenesulfonamide: Part 1
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Treatment of a series of 2,4-dinitrobenzenesulfonamides with various thioacids in the presence of cesium carbonate leads directly to the corresponding amides.
- Messeri, Tommaso,Sternbach, Daniel D.,Tomkinson, Nicholas C. O.
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p. 1669 - 1672
(2007/10/03)
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- Improved functionalized resin for chemical synthesis
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A support functionalized by an indole or pyrrole aldehyde is useful for the solid phase synthesis of amide type compounds.
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- Alkylation of Rink's amide linker on polystyrene resin: A reductive amination approach to modified amine-linkers for the solid phase synthesis of N-substituted amide derivatives
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Reductive amination of aldehydes and ketones using sodium cyanoborohydride and Rink's 4-(2',4'-dimethoxyphenyl-aminomethyl)-phenoxymethyl-linked polystyrene resin [Rink's amine linker on copoly-(styrene-1%-divinylbenzene)]1 2 affords high yields of linker-bound, N-alkyl amines with excellent chemical selectivity. Subsequent coupling with acid derivatives gave derivatized N-substituted amides in excellent yields after cleavage from the solid-support.
- Brown, Edward G.,Nuss, John M.
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p. 8457 - 8460
(2007/10/03)
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- Oxidation of Aromatic Sulfides Photosensitized by TiO2 in CH3CN in the Presence of Ag2SO4. The Role of TiO2 in the Chemistry of Sulfide Radical Cations
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A product study of the photooxidation of the aromatic sulfides 1 - 5 sensitized by TiO2 in MeCN, in the presence of Ag2SO4, has been carried out. With benzyl phenyl sulfide (1), 4-methoxybenzyl phenyl sulfide (2), and phenethyl phenyl sulfide (4), the photooxidation led mainly to aldehydic products, benzaldehyde, 4-methoxybenzaldehyde, and phenylacetaldehyde, respectively. With benzyl 4-methoxyphenyl sulfide (3), the major product was the corresponding sulfoxide. Diphenyl sulfoxide was the only product observed in the oxidation of diphenyl sulfide (5). These results suggest α-C-H deprotonation as the major reaction path for the radical cations of 1, 2, and 4, and an active role in this respect of the oxygenated basic sites present on the TiO2 surface is envisaged. An interaction of these oxygenated centers with the sulfur atom of the adsorbed radical cation is also suggested to explain the remarkable finding that substantial amounts of sulfoxide are observed with 3 and 5, in spite of the fact that the photooxidations were carried under nitrogen. Different than with the sulfides, the photooxidation of 4-methoxybenzyl phenyl sulfoxide leads exclusively to products of C - S bond cleavage, which is attributed to the much greater stability of sulfinyl than thiyl radicals.
- Baciocchi, Enrico,Del Giacco, Tiziana,Ferrero, Marina I.,Rol, Cesare,Sebastiani, Giovanni V.
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p. 4015 - 4017
(2007/10/03)
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- Photoinduced electron transfer reactions of benzyl phenyl sulfides promoted by 9,10-dicyanoanthracene
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The photoinduced oxidation of benzyl phenyl sulfides 1-3 has been investigated in MeCN using 9,10-dicyanoanthracene as sensitizer in the presence of O2. In this reaction a sulfide radical cation is formed, which undergoes one or more of the three main reaction pathways opened to these species: C-S bond cleavage, C-H bond cleavage and S-oxidation. The former route (leading to benzylic products) was observed with all the substrates investigated, whereas the second (leading to benzaldehydes) operates only with 1 and 2. Formation of sulfoxides was found solely in the photooxidation of 1. The influence of substrate structures on the relative contribution of the three pathways as well as the role of O2- in this respect are discussed.
- Baciocchi, Enrico,Crescenzi, Cristina,Lanzalunga, Osvaldo
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p. 4469 - 4478
(2007/10/03)
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- Kinetics and mechanism of aminolysis of phenyl acetates and phenyl trimethylacetates in dimethyl suldoxide
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Kinetic studies have been carried out on the reactions of phenyl acetates and phenyl trimethylacetates in dimethyl sulfoxide.The rate ratios between the two acyl compounds, and the positive sign and large magnitude of the cross-interaction constants, ρXZ, between substituents X in the nucleophile and Z in the leaving group are considered to favour the rate-limiting expulsion of aryl oxide from the tetrahedral intermediate T+/-.The aprotic solvent used makes the proposed mechanism with a cyclic transition state more attractive especially in view of the greater charge dispersion and assistance to leaving group departure provided in such a structure.
- Koh, Han Joong,Kim, Seung Il,Lee, Byung Choon,Lee, Ikchoon
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p. 1353 - 1358
(2007/10/03)
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- Structural Effects in the TiO2-Photocatalyzed Oxidation of Alkylaromatic Compounds in Acetonitrile in the Presence of Ag2SO4
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The TiO2-sensitized photochemical reactions of some alkylbenzenes (ArCH2R; R = H, Me), 1-aryl-2-propanols, and corresponding methyl esters (ArCH2C(OR'')R'CH3; R', R'' = H, Me) have been investigated in MeCN, in the presence of Ag2SO4, which traps the photogenerated electrons.With ArCH2R, the corresponding radical cations are generated by the photoexcited TiO2 and are then deprotonated to from benzyl radicals; from the latter 1,2-diarylethanes, 3-arylpropanonitriles, and benzylacetamides are obtained as major products.With ArCH2C(OR'')R'CH3, the formed radical cations undergo C-C bond cleavage as the only observed route, when Ar = Ph.However, when Ar = 4-MeOPh and R' = H, the radical cation undergoes C-H bond cleavage as the major or exclusive reaction path.These results are compared with those obtained in the corresponding homogeneous photochemical reactions, and their implications with respect to the role of the structure on the side-chain reactivity of aromatic radical cations are discussed.
- Baciocchi, Enrico,Rol, Cesare,Sebastiani, Giovanni V.,Taglieri, Luca
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p. 5272 - 5276
(2007/10/02)
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- The Direct Synthesis of Secondary Amides from Aldehydes; A Novel General Redox Procedure Mediated by Iodotrichlorosilane (ITCS)
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A unique, general redox process for the preparation of secondary amides by the interaction, of aldehydes with nitriles in the presence of two equivalents of iodotrichlorosilane (ITCS) is described and possible pathways are discussed. - Keywords: Iodotrichlorosilane, Aldehydes, Nitriles, sec-Amides
- Elmorsy, Saad S.,Badawy, Doria S.,Nour, Mohamed A.,Kandeel, Ezzat M.
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p. 417 - 421
(2007/10/02)
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- Iron(III) perchlorate - A novel reagent in synthesis
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Iron (III) perchlorate in acetonitrile as the solvent converts alkohols and alkyl halides to acetamide derivatives, cleaves glycols and converts α-hydroxy acids to aldehydes or ketones.
- Kumar, Baldev,Kumar, Harish,Singh, N
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p. 460 - 461
(2007/10/02)
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- A NOVEL ROUTE FOR THE DIRECT SYNTHESIS OF SECONDARY AMIDES FROM ALDEHYDES
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We describe a unique, general redox process for the preparation of secondary amides by the interaction of aldehydes and nitriles in the presence of two equivalents of iodotrichlorosilane (ITCS).
- Elmorsy, Saad S.,Nour, Mohamed A.,Kandeel, Ezzat M.,Pelter, Andrew
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p. 1825 - 1826
(2007/10/02)
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