- Synthesis of a poly(ethylene glycol)-supported tetrakis ammonium salt: A recyclable phase-transfer catalyst of improved catalytic efficiency
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The immobilization of four quaternary ammonium groups on a poly(ethylene glycol) support provided an efficient and recyclable phase-transfer catalyst.
- Benaglia, Maurizio,Cinquini, Mauro,Cozzi, Franco,Tocco, Graziella
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Read Online
- Discovery of allosteric and selective inhibitors of inorganic pyrophosphatase from mycobacterium tuberculosis
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Inorganic pyrophosphatase (PPiase) is an essential enzyme that hydrolyzes inorganic pyrophosphate (PPi), driving numerous metabolic processes. We report a discovery of an allosteric inhibitor (2,4-bis(aziridin-1-yl)-6-(1-phenylpyrrol-2-yl)-s-triazine) of bacterial PPiases. Analogues of this lead compound were synthesized to target specifically Mycobacterium tuberculosis (Mtb) PPiase (MtPPiase). The best analogue (compound 16) with a Ki of 11 μM for MtPPiase is a species-specific inhibitor. Crystal structures of MtPPiase in complex with the lead compound and one of its analogues (compound 6) demonstrate that the inhibitors bind in a nonconserved interface between monomers of the hexameric MtPPiase in a yet unprecedented pairwise manner, while the remote conserved active site of the enzyme is occupied by a bound PPi substrate. Consistent with the structural studies, the kinetic analysis of the most potent inhibitor has indicated that it functions uncompetitively, by binding to the enzyme-substrate complex. The inhibitors appear to allosterically lock the active site in a closed state causing its dysfunctionalization and blocking the hydrolysis. These inhibitors are the first examples of allosteric, species-selective inhibitors of PPiases, serving as a proof-of-principle that PPiases can be selectively targeted.
- Pang, Allan H.,Garzan, Atefeh,Larsen, Martha J.,McQuade, Thomas J.,Garneau-Tsodikova, Sylvie,Tsodikov, Oleg V.
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- Pyrrole synthesis using a tandem Grubbs' carbene-RuCl3 catalytic system
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A straightforward pyrrole synthesis from diallylamines is developed by using a tandem catalyst system leading to ring-closing metathesis with the second generation Grubbs' catalyst (10%) followed by dehydrogenation in the presence of RuCl3 × H2O (2%).
- Dieltiens, Nicolai,Stevens, Christian V.,Vos, David De,Allaert, Bart,Drozdzak, Renata,Verpoort, Francis
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Read Online
- A new method to N-arylmethylenepyrroles from N-acylpyrroles
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An efficient general method for the preparation of N-arylmethylenepyrroles based on the reduction of N-acylpyrroles is reported. The reduction procedure described is sufficiently mild to make it applicable to a variety of sensitive acyl and heterocyclic acyl compounds where reduction results in cleavage of the C-N bond. The method can also be used in the preparation of pyrrole derivatives containing base sensitive protecting groups.
- D'Silva, Claudius,Iqbal, Rifat
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Read Online
- Palladium-promoted 1,4-Cycloamination of 1,3-Dienes to Pyrroles
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1,3-Dienes react with palladium(II) chloride and acetic acid with the formation of 4-acetoxy-alk-2-enyl-palladium complexes (2), which on reaction with primary amines give N-alkylpyrroles.
- Baeckvall, Jan-E.,Nystroem, Jan-E.
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Read Online
- Arylation of indoles using cyclohexanones dually-catalyzed by niobic acid and palladium-on-carbons
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3-Arylindoles were easily constructed from indoles and cyclohexanone derivatives using a combination of catalytic niobic acid-on-carbon (Nb2O5/C) and palladium-on-carbon (Pd/C) under heating conditions without any oxidants. The Lewis acidic Nb2O5/C promoted the nucleophilic addition of indoles to the cyclohexanones, and the subsequent dehydration and Pd/C-catalyzed dehydrogenation produced the 3-arylindoles. The additive 2,3-dimethyl-1,3-butadiene worked as a hydrogen acceptor to facilitate the dehydrogenation step.
- Ban, Kazuho,Sajiki, Hironao,Sawama, Yoshinari,Yamamoto, Yuta
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supporting information
p. 3898 - 3902
(2020/06/03)
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- Lactam derivatives and preparation method and application thereof
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The invention relates to lactam derivatives and a preparation method and application thereof. Compared with the prior art, the invention provides lactam compounds with a novel structure. The compoundsand compositions thereof have remarkable activity in inhibition of the proliferation of cancer cells (including, but not limited to, the liver cancer cell line HepG2 and the lung cancer cell line A549), and the activity of multiple compounds is in the same order of magnitude as the activity of the commercial drug adriamycin or superior to the activity of adriamycin. The compounds of the inventioncan be prepared from N-substituted pyrrole compounds through a reaction, and the preparation method is convenient, rapid and efficient.
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Paragraph 0066-0070
(2020/02/10)
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- Sulfoxide-Promoted Chlorination of Indoles and Electron-Rich Arenes with Chlorine as Nucleophile
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An efficient chlorination of indoles and electron-rich arenes with chlorine anion as nucleophile is described. With the use of ethyl phenyl sulfoxide as the promoter, the reaction went smoothly under metal-free and mild conditions. Various indoles and electron-rich arenes are converted into the corresponding chlorinated compounds in moderate to excellent yields. A plausible interrupted Pummerer reaction mechanism was proposed without the oxidation of chloride anion. In addition, the byproduct thioether could be easily converted to the starting material sulfoxide just by a simple oxidation reaction. (Figure presented.).
- Ji, Yuan-Zhao,Li, Hui-Jing,Wang, Yi-Ruo,Wu, Yan-Chao,Zhang, Zheng-Yan
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supporting information
(2020/02/05)
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- Development of Pd(OAc)2-catalyzed tandem oxidation of C[sbnd]N, C[sbnd]C, and C(sp3)–H bonds: Concise synthesis of 1-aroylisoquinoline, oxoaporphine, and 8-oxyprotoberberine alkaloids
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A catalytic tandem oxidation of C[sbnd]N, C[sbnd]C, and C(sp3)–H bonds is developed. This tandem oxidation is applied to two-step total syntheses of papaveraldine and pulcheotine A. Additionally, the total synthesis of liriodenine is achieved in six steps from homopiperonyl alcohol and 2-bromophenylacetonitrile by applying this catalytic tandem oxidation. Moreover, the direct conversion of xylopinine to 8-oxypseudopalmatine in a 76% yield demonstrates the versatility of this catalytic reaction.
- Nishimoto, Saeko,Nakahashi, Hiromichi,Toyota, Masahiro
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- Anti-inflammatory COX/LOX inhibitor, and preparation method and application thereof
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The invention provides an anti-inflammatory COX/LOX inhibitor, and a preparation method and an application thereof. The inhibitor is a compound represented by formula I, or a pharmaceutically acceptable salt thereof. The novel anti-inflammatory COX/LOX inhibitor can significantly reduce the ear swelling degree of mice in an administrated group in xylene-induced ear swelling test, so the compound has an anti-inflammatory effect, and the anti-inflammatory effect of the compound is equivalent with that of aspirin; and additionally, pharmacological tests show that the compound has small irritationto the gastrointestinal tract. The preparation method of the novel anti-inflammatory COX/LOX inhibitor has the advantages of simplicity, easiness in operation, and effectiveness in the reduction of the production cost to realize industrial production.
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Paragraph 0054-0056
(2019/04/10)
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- An enantioselective synthesis of α-alkylated pyrroles: Via cooperative isothiourea/palladium catalysis
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Herein we describe the direct enantioselective Lewis base/Pd catalysed α-allylation of pyrrole acetic acid esters. This provides high isolated yields of highly enantioenriched products and exhibits broad reaction scope with respect to both reaction partners. The products can be readily elaborated in a manner which points towards potential applications in target directed synthesis.
- Rush Scaggs,Scaggs, Toya D.,Snaddon, Thomas N.
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supporting information
p. 1787 - 1790
(2019/02/20)
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- Sustainable Manganese-Catalyzed Solvent-Free Synthesis of Pyrroles from 1,4-Diols and Primary Amines
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A general and selective metal-catalyzed conversion of biomass-derived primary diols and amines to the highly valuable 2,5-unsubstituted pyrroles has been developed. The reaction is catalyzed by a stable nonprecious manganese complex (1 mol %) in the absence of organic solvents whereby water and molecular hydrogen are the only side products. The manganese catalyst shows unprecedented selectivity, avoiding the formation of pyrrolidines, cyclic imides, and lactones.
- Borghs, Jannik C.,Lebedev, Yury,Rueping, Magnus,El-Sepelgy, Osama
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supporting information
p. 70 - 74
(2019/01/11)
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- Multifunctional 2- and 3-Fluoropyrroles
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Sequential reaction cascades for the synthesis of polysubstituted 2- and 3-fluoropyrrole derivatives from common polybromopyrrole precursors have been developed. A strategic variation of a combination of regioselective debromolithiation followed by trapping of the corresponding carbanions by electrophilic fluorination and Pd catalysed cross-coupling reactions allows access to polyfunctional fluoropyrrole products by methodology applicable to drug discovery programs, extending the range of five-membered fluoroazaheteroaromatic derivatives potentially available for incorporation into screening libraries.
- Heeran, Darren,Sandford, Graham
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supporting information
p. 2339 - 2343
(2019/02/27)
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- Nickel-Catalyzed Synthesis of N-Substituted Pyrroles Using Diols with Aryl- and Alkylamines
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Herein, nickel-catalyzed sustainable strategy for the synthesis of N-substituted pyrroles using butene-1,4-diols and butyne-1,4-diols with a series of aryl-, alkyl-, and heteroarylamines is reported. The catalytic protocol is tolerant of free alcohol, halide, alkyl, alkoxy, oxygen heterocycles, activated benzyl, and the pyridine moiety and resulted in up to 90% yield. Initial mechanistic studies involving defined nickel catalyst, determination of rate, and order of reaction including deuterium-labeling experiments were performed for pyrrole synthesis.
- Singh, Khushboo,Kabadwal, Lalit Mohan,Bera, Sourajit,Alanthadka, Anitha,Banerjee, Debasis
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supporting information
p. 15406 - 15414
(2019/01/04)
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- Solvent Free Synthesis of N-Substituted Pyrrole Derivatives Catalyzed by Silica Sulfuric Acid
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Sulfuric acid immobilized on silica gel is used as an efficient catalyst in the synthesis of N-substituted pyrrole derivatives by the Clauson–Kaas pyrrole synthesis. The solvent free reaction mixture is stirred by grinding. Within very short reaction time the process leads to the corresponding products without any decomposition recorded.
- Khammas,Yolacan,Aydogan
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p. 2680 - 2683
(2019/04/04)
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- Synthesizing process of nitrogen-heterocyclic high-selectivity aldehyde
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The invention relates to a synthesizing process of nitrogen-heterocyclic high-selectivity aldehyde. The synthesizing process is characterized in that when nitrogen-heterocyclic nitrogen atoms have hydrogen atoms, pyrrole, piperidine and pyrazole are used as the initial raw materials, and the pyrrole, the piperidine and the pyrazole are allowed to have reaction with piperidine-1-formaldehyde under nitrogen atom protection to obtain required nitrogen-atom ortho-position aldehyde; when nitrogen-heterocyclic nitrogen atoms have no hydrogen atoms, pyridine and pyrimidine are used to have reaction with the piperidine-1-formaldehyde to obtain the required nitrogen-atom ortho-position aldehyde. The synthesizing process is simple to operate, few in steps and high in selectivity and is a universal method using nitrogen heterocycle to synthesize the nitrogen ortho-position aldehyde.
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Paragraph 0014; 0017; 0018; 0030; 0031; 0043; 0044
(2017/09/05)
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- Unveiling the Biocatalytic Aromatizing Activity of Monoamine Oxidases MAO-N and 6-HDNO: Development of Chemoenzymatic Cascades for the Synthesis of Pyrroles
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A chemoenzymatic cascade process for the sustainable production of pyrroles has been developed. Pyrroles were synthesized by exploiting the previously unexplored aromatizing activity of monoamine oxidase enzymes (MAO-N and 6-HDNO). MAO-N/6-HDNO whole cell biocatalysts are able to convert 3-pyrrolines into pyrroles under mild conditions and in high yields. Moreover, MAO-N can work in combination with the ruthenium Grubbs catalyst, leading to the synthesis of pyrroles from diallylamines/-anilines in a one-pot cascade metathesis-aromatization sequence.
- Scalacci, Nicoló,Black, Gary W.,Mattedi, Giulio,Brown, Nicola L.,Turner, Nicholas J.,Castagnolo, Daniele
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p. 1295 - 1300
(2017/08/09)
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- Iron-catalyzed sustainable synthesis of pyrrole
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Efficient, sustainable, highly regiospecific substituted pyrroles were synthesized using a well-defined, air stable, molecular iron(0) complex. The developed methodology is broadly applicable and tolerates a variety of functional groups. C-2, C-3, and C-2 & C-4 substituted pyrroles were synthesized in good yield. Symmetrical bis-pyrroles were accessible for the first time using an iron catalyst. On the basis of the experimental observation, we propose that the reaction proceeds through a hydrogen autotransfer process followed by second oxidation/ intramolecular dehydrative condensation to provide the pyrrole.
- Emayavaramban, Balakumar,Sen, Malay,Sundararaju, Basker
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supporting information
p. 6 - 9
(2017/11/28)
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- Palladium-Catalyzed Regioselective Dehydrogenative C–H/C–H Cross-Coupling of Pyrroles and Pyridine N-Oxides
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The palladium-catalyzed cross-dehydrogenative coupling of N-alkylpyrroles and pyridine N-oxides gave the corresponding pyrrolylpyridine N-oxides. Cu(OAc)2·H2O as a co-catalyst with air as the terminal oxidant led to preferential coupling in the β-position, whereas AgOAc as the stoichiometric oxidant resulted in preferential coupling in the α-position. N-(Benzyloxymethyl)pyrrole derivatives were deprotected by hydrogenolysis followed by basic hydrolysis.
- Liu, Shanshan,Tzschucke, C. Christoph
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supporting information
p. 3509 - 3513
(2016/07/28)
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- Indium-Catalyzed Formal N-Arylation and N-Alkylation of Pyrroles with Amines
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Under indium Lewis acid catalysis, a nitrogen atom of N-unsubstituted pyrroles was replaced with a nitrogen atom of primary amines, thereby producing N-aryl- and N-alkylpyrroles. This system formally introducing such carbon frameworks to the pyrrole nitrogen atom shows unique selectivity: only the H?N(pyrrolyl) unit undergoes the N-arylation and N-alkylation even in the coexistence of a similar H?N(indolyl) part; and an aryl–halogen bond remains intact. These are clearly different from the typical method depending on the C?N(pyrrolyl) bond-forming reaction with organic halides as substrates. From a viewpoint of pyrrole N-protection–deprotection chemistry, worth noting is that a methyl group on the pyrrole nitrogen atom can be removed, albeit in a formal way. (Figure presented.).
- Yonekura, Kyohei,Oki, Kenji,Tsuchimoto, Teruhisa
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supporting information
p. 2895 - 2902
(2016/09/16)
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- Sustainable Pathways to Pyrroles through Iron-Catalyzed N-Heterocyclization from Unsaturated Diols and Primary Amines
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Pyrroles are prominent scaffolds in pharmaceutically active compounds and play an important role in medicinal chemistry. Therefore, the development of new, atom-economic, and sustainable catalytic strategies to obtain these moieties is highly desired. Direct catalytic pathways that utilize readily available alcohol substrates have been recently established; however, these approaches rely on the use of noble metals such as ruthenium or iridium. Here, we report on the direct synthesis of pyrroles using a catalyst based on the earth-abundant and inexpensive iron. The method uses 2-butyne-1,4-diol or 2-butene-1,4-diol that can be directly coupled with anilines, benzyl amines, and aliphatic amines to obtain a variety of N-substituted pyrroles in moderate-to-excellent isolated yields.
- Yan, Tao,Barta, Katalin
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p. 2321 - 2325
(2016/10/24)
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- A novel and convenient method for the preparation of 5-(diphenylmethylene)-1H-pyrrol-2(5H)-ones; synthesis and mechanistic study
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An efficient, regioselective synthesis has been developed for the preparation of 5-(diphenylmethylene)-1H-pyrrol-2(5H)-ones from readily available 1H-pyrroles by sequential dibromination and selective organometallic bromine/lithium exchange followed by reaction with benzophenone. Comparison of various N-substituents was shown to demonstrate the high tolerance of the transformation to functional groups. The structures of the new products were determined by spectroscopic methods and confirmed by single-crystal X-ray diffraction measurement. In addition, theoretical study of the reaction mechanism and selective functionalization of the endocyclic double bond were also presented.
- Faigl, Ferenc,Deák, Szilvia,Mucsi, Zoltán,Hergert, Tamás,Balázs, László,Sándor, Boros,Balázs, Barbara,Holczbauer, Tamás,Nyerges, Miklós,Mátrav?lgyi, Béla
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p. 5444 - 5455
(2016/08/04)
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- A simple and convenient method for the synthesis of N, N-diaryl tertiary amines
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Direct preparation of tertiary amines in which two substituents are aromatic is described. In the presence of either the inorganic base sodium tert-butoxide or the sterically hindered organic base diisopropylethylamine, the alkylation of secondary diarylamines is achieved smoothly. In contrast to methods previously reported in the literature, this procedure is high-yielding and does not require the use of transition-metal catalysts or functional-group-intolerant hydride reductants. Georg Thieme Verlag Stuttgart ? New York.
- Wekesa, Francis S.,Phadke, Neha,Jahier, Claire,Cordes, David B.,Findlater, Michael
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p. 1046 - 1051
(2014/05/06)
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- An elegant protocol for the synthesis of N-substituted pyrroles through C-N cross coupling/aromatization process using CuFe2O4 nanoparticles as catalyst under ligand-free conditions
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A simple and efficient, ligand-free C-N cross-coupling of aryl halides/benzyl bromides with trans-4-hydroxy-l-proline has been developed to produce aromatized N-substituted pyrroles, using a catalytic amount of magnetically separable and recyclable CuFe2O4 nanoparticles, in the presence of Cs2CO3 in DMSO at 100 °C.
- Satish,Reddy, K. Harsha Vardhan,Ramesh,Kumar, B.S.P. Anil,Nageswar
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supporting information
p. 2596 - 2599
(2014/05/06)
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- Synthesis of N-alkyl pyrroles via decarboxylation/dehydration in neutral ionic liquid under catalyst-free conditions
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A general route to N-alkyl pyrroles by reacting aromatic, heteroaromatic or aliphatic aldehydes with 4-hydroxyproline in ionic liquid under neutral condition was developed. The ionic liquid can be readily recovered and reused for up to 5 reaction cycles without any effect on the yield of the product formed. The utility of the protocol for the one-pot synthesis of 9H-benzo[e]pyrrolo[2,1-b][1,3]oxazines is also presented.
- Yadav, Veena D.,Dighe, Shashikant U.,Batra, Sanjay
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p. 57587 - 57590
(2015/01/08)
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- Copper-catalyzed domino homologation and cycloisomerization reactions for 3-pyrroline synthesis
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Copper bromide was found to be an efficient catalyst for a domino reaction sequence leading to 3-pyrrolines. The Cu(I)-catalyzed Crabbe reaction of propargyl sulfonamide and selective cycloisomerization of the allene intermediate were carried out using microwave irradiation conditions affording a wide range of 2-substituted- and 2,5-disubstituted-3-pyrrolines. Mechanistic studies of the reaction intermediates revealed two possible reaction pathways; both invoke the importance of vinyl copper intermediates.
- Shin, Ye Ho,Maheswara, Muchchintala,Hwang, Joon Young,Kang, Eun Joo
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p. 2305 - 2311
(2014/04/17)
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- First total synthesis of isoquinolinone alkaloid marinamide and its methyl ester
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The first total synthesis of isoquinolinone alkaloid marinamide 1 and its methyl ester 2 was described. The key steps involved a regioselective Friedel-Crafts reaction of 1-benzyl-1H-pyrrole to form the intermediate 8.
- Feng, Cheng-Liang,Zhang, Shu-Guang,Chen, Jun-Qing,Cai, Jin,Ji, Min
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p. 767 - 769
(2013/07/26)
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- Total synthesis of a novel isoquinolinone alkaloid marinamide and its methyl ester
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A naturally occurring isoquinolinone alkaloid marinamide and its methyl ester were synthesised from phthalic anhydride over eight steps in 46% and 52% overall yield. The key intermediate methyl 2-(1-benzyl-1H-pyrrole-2-carbonyl) benzoate was synthesised from the acid chloride of mono methyl phthalate and 1-benzyl-1H-pyrrole catalysed by Zinc oxide under solvent-free conditions at room temperature.
- Zhang, Shuguang,Feng, Chengliang,Cai, Jin,Chen, Junqing,Ji, Min
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p. 291 - 293
(2013/07/27)
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- Suzuki-miyaura cross-coupling of potassium trifluoro(N -methylheteroaryl) borates with aryl and heteroaryl halides
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The synthesis of potassium trifluoro(N-methylheteroaryl)borates and their use in cross-coupling reactions with various aryl and heteroaryl halides to construct N-methyl heteroaryl-substituted aromatic and heteroaromatic compounds are reported.
- Molander, Gary A.,Ryu, Daweon,Hosseini-Sarvari, Mona,Devulapally, Rammohan,Seapy, Dave G.
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p. 6648 - 6656
(2013/07/26)
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- Direct functionalization of tetrahydrofuran and 1,4-dioxane: Nickel-catalyzed oxidative C(sp3)-H arylation
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CHoose nickel: The nickel-catalyzed oxidative arylation of C(sp 3)-H bonds has been achieved. Several substituted arylboronic acids and various C(sp3)-H bonds were found to be suitable substrates for this novel transformation, which is likely to proceed through a radical pathway. This method allows the introduction of simple ether derivatives to construct α-arylated ethers. FG=functional group. Copyright
- Liu, Dong,Liu, Chao,Li, Heng,Lei, Aiwen
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supporting information
p. 4453 - 4456
(2013/05/21)
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- Organic synthesis via magnetic attraction: Benign and sustainable protocols using magnetic nanoferrites
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Magnetic nano-catalysts have been prepared using simple modification of iron ferrites. The nm size range of these particles facilitates the catalysis process, as an increased surface area is available for the reaction; the easy separation of the catalysts by an external magnet and their recovery and reuse are additional beneficial attributes. Glutathione bearing nano-ferrites have been used as organocatalysts for the Paal-Knorr reaction and homocoupling of boronic acids. Nanoferrites, post-synthetically modified by ligands, were used to immobilize nanometals (Cu, Pd, Ru, etc.) which enabled the development of efficient, sustainable and green procedures for azide-alkynes-cycloaddition (AAC) reactions, C-S coupling, O-allylation of phenol, Heck-type reactions and hydration of nitriles.
- Nasir Baig,Varma, Rajender S.
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p. 398 - 417
(2013/03/14)
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- A general method for palladium-catalyzed direct carbonylation of indole with alcohol and phenol
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A novel strategy involving a first oxidative iodination and subsequent Pd0-catalyzed carbonylation to yield indole-3-carboxylate has been developed. It showed perfect generality to indole, alcohol, and phenol. The current methodology could also be conveniently applied to the synthesis of biologically active tropisetron from simple indole and tropine.
- Lang, Rui,Shi, Lijun,Li, Dengfeng,Xia, Chungu,Li, Fuwei
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supporting information; experimental part
p. 4130 - 4133
(2012/10/07)
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- Synthesis, reactions, and rearrangements of 2,4-diazabicyclo[3.1.0]hexan-3- ones
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Copper-mediated cyclopropanation of 1,3-dialkyl-1,3- dihydroimidazol-2-ones with diazomethane and methyl diazoacetate yields 2,4-diazabicyclo[3.1.0]hexan- 3-ones and the first diaza[4.3.1]propellane. The bicyclic system survives elevated temperatures and in strongly basic and acidic solutions, but drastic conditions cleave the (C-1)-(C-6) bond affording 1,3-dihydroimidazol-2-ones. Catalytic hydrogenation removes N-benzyl groups and opens the (C-1)-(C-6) bond. Lithium aluminium hydride reduces 2,4-dibenzyl-2,4-diazabicyclo[3.1.0]hexan-3- one to a bicyclic aminal. Acid-induced cleavage of its imidazolidine ring is followed by unexpected transformations that probably procede via an acyclic intermediate, which comprises an azomethine ylide and an iminium moiety. 1,3-Cyclization involving both functional groups leads to N,N'-dibenzyl-trans-1, 2-cyclopropanediamine, while 1,5-cyclization gives rise to the formation of N-benzylpyrrole along with N-benzylamine.
- Helmut, C.,Stawitz, Josef Walter,Mueller, Bodo
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p. 2449 - 2463,15
(2020/08/24)
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- A new facile approach to N-alkylpyrroles from direct redox reaction of 4-hydroxy-l-proline with aldehydes
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An unprecedented acetic acid-catalyzed efficient access to N-alkylpyrroles from reaction of 4-hydroxy-l-proline with a variety of aldehydes has been achieved in good to excellent yields under mild reaction conditions.
- Zou, Zhiqin,Deng, Zejun,Yu, Xinhong,Zhang, Manman,Zhao, Sihan,Luo, Ting,Yin, Xin,Xu, Hui,Wang, Wei
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experimental part
p. 43 - 49
(2012/03/13)
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- O-Iodoxybenzoic acid (IBX): A versatile reagent for the synthesis of N-substituted pyrroles mediated by β-cyclodextrin in water
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O-Iodoxybenzoic acid (IBX), a very mild and efficient hypervalent iodine(V) reagent, aromatizes diversely substituted 1-benzylpyrrolidines and N-substituted l-proline analogues to the corresponding substituted pyrroles in good to excellent yields under mild conditions mediated by β-cyclodextrin in water at room temperature. To the best of our knowledge, this is the first report on IBX, promoting complete aromatization leading to N-benzylpyrroles from the corresponding saturated five membered heterocyclic derivatives in water medium.
- Narayana Murthy,Nageswar
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supporting information; experimental part
p. 4481 - 4484
(2011/09/19)
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- Decarboxylative formation of N-alkyl pyrroles from 4-hydroxyproline
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N-Alkyl pyrroles are obtained in a single step from 4-hydroxyproline and aldehydes in just 15 min under microwave irradiation.
- Deb, Indubhusan,Coiro, Daniel J.,Seidel, Daniel
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scheme or table
p. 6473 - 6475
(2011/06/28)
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- Magnetic Nanoparticle-Supported Glutathione as a Sustainable Organocatalyst
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This invention relates to the use of nano-organocatalysts, and, more specifically, to the use of magnetic nanomaterial-supported organocatalysts. It is an object of the present invention to provide “green” catalysts and protocols. According to one embodiment of the invention, a nano-organocatalyst in the form of a magnetic nanomaterial-supported organocatalyst is provided. According to other embodiments of the invention, glutathione and cysteine are provided as organocatalysts and magnetic nanomaterial-supported glutathione and magnetic nanomaterial-supported cysteine are provided for use as nano-organocatalysts. According to another embodiment of the invention, a method of using a recyclable magnetic nanomaterial-supported organocatalyst using a totally benign aqueous protocol, without using any organic solvent in the reaction or during the workup, is provided. According to a further embodiment of the invention, a recyclable magnetic nanomaterial-supported organocatalyst for various organocatalytic reactions, including but not limited to Paal-Knorr reactions, aza-Michael addition and pyrazole synthesis, is provided.
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Page/Page column 6; 8
(2011/04/14)
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- Friedel - Crafts acylation of pyrroles and indoles using 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) as a nucleophilic catalyst
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1,5-Diazabicyclo[4.3.0]non-5-ene (DBN) has been shown to be an effective catalyst for the regioselective Friedel - Crafts C-acylation of pyrroles and indoles in high yields. A detailed mechanistic study implies that DBN is acting as a nucleophilic organocatalyst, with the X-ray crystal structure of a key N-acyl-amidine intermediate having been determined for the first time.
- Taylor, James E.,Jones, Matthew D.,Williams, Jonathan M. J.,Bull, Steven D.
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supporting information; experimental part
p. 5740 - 5743
(2011/03/18)
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- Nano-organocatalyst: magnetically retrievable ferrite-anchored glutathione for microwave-assisted Paal-Knorr reaction, aza-Michael addition, and pyrazole synthesis
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Postsynthetic surface modification of magnetic nanoparticles by glutathione imparts desirable chemical functionality and enables the generation of catalytic sites on the surfaces of ensuing organocatalysts. In this article, we discuss the developments, unique activity, and high selectivity of nano-organocatalysts for microwave-assisted Paal-Knorr reaction, aza-Michael addition, and pyrazole synthesis. Their insoluble character coupled with paramagnetic nature enables easy separation of these nano-catalysts from the reaction mixture using external magnet, which eliminates the requirement of catalyst filtration.
- Polshettiwar, Vivek,Varma, Rajender S.
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experimental part
p. 1091 - 1097
(2010/03/25)
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- Magnetic nanoparticle-supported glutathione: A conceptually sustainable organocatalyst
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A conceptually novel nanoparticle-supported and magnetically recoverable organocatalyst has been developed, which is readily prepared from inexpensive starting materials in a truly sustainable manner; which catalyzes the Paal-Knorr reaction with high yield in pure aqueous medium that avoids the use of toxic organic solvents, even in the workup step.
- Polshettiwar, Vivek,Baruwati, Babita,Varma, Rajender S.
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supporting information; experimental part
p. 1837 - 1839
(2009/10/23)
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- Iron-catalyzed inexpensive and practical synthesis of N-substituted pyrroles in water
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An operationally simple, practical, and economical protocol for iron(III) chloride catalyzed Paal-Knorr pyrrole synthesis in water in good to excellent yields has been developed. Several N-substituted pyrroles are readily prepared from the reaction of 2,5-dimethoxytetrahydrofuran and aryl/alkyl, sulfonyl and acyl amines under very mild reaction conditions. Georg Thieme Verlag Stuttgart.
- Azizi, Najmedin,Khajeh-Amiri, Alireza,Ghafuri, Hossein,Bolourtchian, Mohammad,Saidi, Mohammad Reza
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experimental part
p. 2245 - 2248
(2009/12/03)
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- Synthesis of (1H-pyrrol-2-ylsulfanyl)alkanoic acids
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(1-Benzyl-1H-pyrrol-2-ylsulfanyl)acetic acid, 2- and 3-(1-benzyl-1H-pyrrol- 2-ylsulfanyl)propionic acids, 1,1′-[1,4-phenylenebis(methylene)]bis[(1H- pyrrol-2-ylsulfanyl)acetic acid], and 1,1′-(hexane-1,6-diyl)bis-[(1H- pyrrol-2-ylsulfanyl)acetic acid] were synthesized for the first time by reactions of 1-benzyl-1H-pyrrole, 1,1′-[1,4-phenylenebis(methylene)] bis(1H-pyrrole), and 1,1′-(hexane-1,6-diyl)bis(1H-pyrrole) with thiourea, iodine, and the corresponding halogen-substituted alkanoic acids. 1-(4-Nitrophenyl)-1H-pyrrole failed to react with thiourea and iodine.
- Rudyakova,Mirskova,Levkovskaya
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experimental part
p. 1517 - 1521
(2009/06/21)
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- Effects of N-pyrrole substitution on the anti-biofilm activities of oroidin derivatives against Acinetobacter baumannii
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Bacteria of the genus Acinetobacter spp. are rapidly emerging as problematic pathogens in healthcare settings. This is exacerbated by the bacteria's ability to form robust biofilms. Marine natural products incorporating a 2-aminoimidazole (2-AI) motif, namely from the oroidin class of marine alkaloids, have served as a unique scaffold for developing molecules that have the ability to inhibit and disperse bacterial biofilms. Herein we present the anti-biofilm activity of a small library of second generation oroidin analogues against the bacterium Acinetobacter baumannii.
- Richards, Justin J.,Reed, Catherine S.,Melander, Christian
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supporting information; scheme or table
p. 4325 - 4327
(2009/04/06)
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- Catalytic investigations of calix[4]arene scaffold based phase transfer catalyst
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Calix[4]arene scaffold based quaternary ammonium salts as multi-site phase transfer catalysts were prepared and their catalytic activities were investigated for Darzens condensation, O/N-alkylation reactions and ethyl benzene oxidation. These calix[4]arene based multi-site phase transfer catalysts showed significant high catalytic activity as compared to single-site phase transfer catalysts.
- Srivastava, Pallavi,Srivastava, Rajendra
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p. 4489 - 4493
(2008/02/03)
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- Reversion of Paal-Knorr synthesis: A new strategy for ring-opening and N-substituent change in 1H-pyrroles
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1H-Pyrroles were converted into 1,4-dicarbonyl compounds, and then into 1H-pyrroles with a different N-substituent by heating at 110 °C under nitrogen in 0.3 M sodium citrate buffer, pH 3, and in the presence of alkyl or aryl amines. The new pyrroles were obtained in low to very high yields depending upon the pH, the reaction time, the initial pyrrole and amine involved, and the proportion between both reagents. Georg Thieme Verlag Stuttgart.
- Zamora, Rosario,Hidalgo, Francisco J.
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p. 1428 - 1430
(2007/10/03)
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- Amine degradation by 4,5-epoxy-2-decenal in model systems
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The reactions of 4,5-epoxy-2-decenal with octylamine, benzylamine, and 2-phenylglycine methyl ester were studied to investigate if amines may suffer a Strecker type degradation by epoxyalkenals analogously to amino acids. In addition to other reactions, the studied amines were converted into their corresponding Strecker aldehydes (octanal, benzaldehyde, and methyl 2-oxo-2-phenylacetate, respectively) to an extent that depended on the pH, the temperature, the amount of epoxyalkenal, and the amine involved. Each amine exhibited an optimum pH for the reaction, but the corresponding Strecker aldehydes were produced to a significant extent within a broad pH range. In addition, the temperature mostly influenced the reaction rate, which was increased between 6.5 and 9.5 times when the reaction was carried out at 60°C than when it took place at 37°C. Furthermore, Strecker aldehyde formation was linearly correlated with the amount of the epoxyalkenal present in the reaction mixture. Nevertheless, the reaction yield mostly depended on the amine involved. Thus, octylamine only produced trace amounts of octanal, benzylamine was converted into benzaldehyde with a yield of 4.3%, and 2-phenylglycine methyl ester was converted into methyl 2-oxo-2-phenylacetate with a reaction yield of 49%. All of these results suggest that suitable amines can be degraded by epoxyalkenals to their corresponding Strecker aldehydes to a significant extent.
- Zamora, Rosario,Gallardo, Emerenciana,Hidalgo, Francisco J.
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p. 2398 - 2404
(2007/10/03)
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- Organic reactions in ionic liquids: A simple and highly regioselective N-substitution of pyrrole
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In ionic liquids [Bmim][PF6] or [Bmim][BF4], pyrrole replaced the halogen atom of an alkyl halide to give the corresponding N-substituted pyrrole in excellent yield. Benzenesulfonyl chloride, p-methylbenzenesulfonyl chloride and benzoyl chloride reacted similarly with pyrroles to afford the N-substituted pyrroles in quantitative yield. Michael addition reaction of pyrrole with electrophilic olefins was completed in a highly regioselective manner to afford the N-alkylpyrroles.
- Le, Zhang-Gao,Chen, Zhen-Chu,Hu, Yi,Zheng, Qin-Guo
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p. 1951 - 1954
(2007/10/03)
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- Use of DOE for rapid development of a red-Al reduction process for the synthesis of 3,4-isopropylidenedioxypyrrolidine hydrotosylate
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Statistical design of experiments (DOE) was used to rapidly optimize Red-Al reduction of an imide to produce, after deprotection and salt formation, 3,4-isopropylidenedioxypyr-rolidine hydrotosylate (1), an intermediate in the synthesis of Ingliforib. A Red-Al reduction process was successfully scaled to produce multikilogram quantities of 1, thus demonstrating a safer and more economical process. Further development resulted in an optimized procedure, which not only avoided borane reduction but also allowed the three-step procedure to be performed without isolation of the intermediates, solvent exchange, or distillation.
- Alimardanov, Asaf R.,Barrila, Mark T.,Busch, Frank R.,Carey, James J.,Couturier, Michel A.,Cui, Curtis
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p. 834 - 837
(2013/09/03)
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- N-Alkylation of anilines, carboxamides and several nitrogen heterocycles using CsF-Celite/alkyl halides/CH3CN combination
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It has been found that the N-alkylation of aniline, carboxamides and heterocyclic compounds bearing an acidic hydrogen atom attached to nitrogen can be accomplished with alkyl halides in acetonitrile and cesium fluoride-celite employed as a solid base. In this manner, pyrrole, indole, pyrazole, imidazole, benzimidazole, carbazole, phthalimide, indazole, indoline, 2-pyrrolidinone, piperidine and 1,2,4-triazole can be successfully alkylated. The procedure is convenient, efficient and generally gives rise to the N-alkylated product exclusively.
- Hayat, Safdar,Atta-Ur-Rahman,Iqbal Choudhary,Khan, Khalid Mohammed,Schumann, Wilhelm,Bayer, Ernst
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p. 9951 - 9957
(2007/10/03)
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- A poly(ethylene glycol)-supported quaternary ammonium salt: An efficient, recoverable, and recyclable phase-transfer catalyst
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(matrix presented) A quaternary ammonium salt readily immobilized on a soluble poly(ethylene glycol) polymer support efficiently catalyzes different reactions carried out under phase-transfer catalysis conditions; the catalyst, easily recovered by precipitation and filtration, shows no appreciable loss of activity when recycled three times.
- Annunziata, Rita,Benaglia, Maurizio,Cinquini, Mauro,Cozzi, Franco,Tocco, Graziella
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p. 1737 - 1739
(2007/10/03)
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