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Artículos de revistas sobre el tema "Electrophilic nitrogens"

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Autor: Grafiati

Publicado: 27 de febrero de 2024

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1

Aeyad, Tahani, Jason Williams, Anthony Meijer y Iain Coldham. "Lithiation–Substitution of N-Boc-2-phenylazepane". Synlett 28, n.º 20 (17 de agosto de 2017): 2765–68. http://dx.doi.org/10.1055/s-0036-1590857.

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Preparation of 2,2-disubstituted azepanes was accomplished from N-tert-butoxy(N-Boc)-2-phenylazepane by treatment with butyllithium then electrophilic quench. The lithiation was followed by in situ ReactIR spectroscopy and the rate of rotation of the carbamate was determined by variable temperature (VT)-NMR spectroscopy and by DFT studies. Most electrophiles add α to the nitrogen atom but cyanoformates and chloroformates gave ortho-substituted products. Cyclic carbamates were formed from an aldehyde or ketone electrophile. Kinetic resolution with sparteine was only poorly selective. Removal of the Boc group promoted cyclization to a homoindolizidine or an isoindolinone.

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2

LEVONEN, Anna-Liisa, Aimee LANDAR, Anup RAMACHANDRAN, Erin K. CEASER, Dale A. DICKINSON, Giuseppe ZANONI, Jason D. MORROW y Victor M. DARLEY-USMAR. "Cellular mechanisms of redox cell signalling: role of cysteine modification in controlling antioxidant defences in response to electrophilic lipid oxidation products". Biochemical Journal 378, n.º 2 (1 de marzo de 2004): 373–82. http://dx.doi.org/10.1042/bj20031049.

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The molecular mechanisms through which oxidized lipids and their electrophilic decomposition products mediate redox cell signalling is not well understood and may involve direct modification of signal-transduction proteins or the secondary production of reactive oxygen or nitrogen species in the cell. Critical in the adaptation of cells to oxidative stress, including exposure to subtoxic concentrations of oxidized lipids, is the transcriptional regulation of antioxidant enzymes, many of which are controlled by antioxidant-responsive elements (AREs), also known as electrophile-responsive elements. The central regulator of the ARE response is the transcription factor Nrf2 (NF-E2-related factor 2), which on stimulation dissociates from its cytoplasmic inhibitor Keap1, translocates to the nucleus and transactivates ARE-dependent genes. We hypothesized that electrophilic lipids are capable of activating ARE through thiol modification of Keap1 and we have tested this concept in an intact cell system using induction of glutathione synthesis by the cyclopentenone prostaglandin, 15-deoxy-Δ12,14-prostaglandin J2. On exposure to 15-deoxy-Δ12,14-prostaglandin J2, the dissociation of Nrf2 from Keap1 occurred and this was dependent on the modification of thiols in Keap1. This mechanism appears to encompass other electrophilic lipids, since 15-A2t-isoprostane and the lipid aldehyde 4-hydroxynonenal were also shown to modify Keap1 and activate ARE. We propose that activation of ARE through this mechanism will have a major impact on inflammatory situations such as atherosclerosis, in which both enzymic as well as non-enzymic formation of electrophilic lipid oxidation products are increased.

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3

Ceaser, E. K., D. R. Moellering, S. Shiva, A. Ramachandran, A. Landar, A. Venkartraman, J. Crawford et al. "Mechanisms of signal transduction mediated by oxidized lipids: the role of the electrophile-responsive proteome". Biochemical Society Transactions 32, n.º 1 (1 de febrero de 2004): 151–55. http://dx.doi.org/10.1042/bst0320151.

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Cellular redox signalling is mediated by the post-translational modification of proteins by reactive oxygen/nitrogen species or the products derived from their reactions. In the case of oxidized lipids, several receptor-dependent and -independent mechanisms are now emerging. At low concentrations, adaptation to oxidative stress in the vasculature appears to be mediated by induction of antioxidant defences, including the synthesis of the intracellular antioxidant glutathione. At high concentrations apoptosis occurs through mechanisms that have yet to be defined in detail. Recent studies have revealed a mechanism through which electrophilic lipids, formed as the reaction products of oxidation, orchestrate these adaptive responses in the vasculature. Using a proteomics approach, we have identified a subset of proteins in cells that we term the electrophile-responsive proteome. Electrophilic modification of thiol groups in these proteins can initiate cell signalling events through the transcriptional activation of genes regulated by consensus sequences for the antioxidant response element found in their promoter regions. The insights gained from our understanding of the biology of these mechanisms will be discussed in the context of cardiovascular disease.

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4

Palillero-Cisneros, Angel, Paola G. Gordillo-Guerra, Fernando García-Alvarez, Olivier Jackowski, Franck Ferreira, Fabrice Chemla, Joel L. Terán y Alejandro Perez-Luna. "α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping". Beilstein Journal of Organic Chemistry 19 (21 de septiembre de 2023): 1443–51. http://dx.doi.org/10.3762/bjoc.19.103.

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We demonstrate that α-(aminomethyl)acrylates are suitable acceptors for 1,4-additions of dialkylzincs in aerobic conditions. The air-promoted radical–polar crossover process involves the 1,4-addition of an alkyl radical followed by homolytic substitution at the zinc atom of dialkylzinc. Coordination of the nitrogen atom to zinc enables this SH2 process which represents a rare example of alkylzinc-group transfer to a tertiary α-carbonyl radical. The zinc enolate thus formed readily undergoes β-fragmentation unless it is trapped by electrophiles in situ. Enolates of substrates having free N–H bonds undergo protodemetalation to provide ultimately the 1,4-addition adduct. In the presence of carbonyl acceptors, aldol condensation occurs providing overall a tandem 1,4-addition–aldol process. When a tert-butanesulfinyl moiety is present on the nitrogen atom, these electrophilic substitution reactions occur with good levels of chiral induction, paving the way to enantioenriched β2-amino acids and β2,2-amino acids.

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5

Cao, Chengyao, Jinyu Sheng y Chao Chen. "Cu-Catalyzed Cascade Annulation of Diaryliodonium Salts and Nitriles: Synthesis of Nitrogen-Containing Heterocycles". Synthesis 49, n.º 23 (11 de octubre de 2017): 5081–92. http://dx.doi.org/10.1055/s-0036-1589515.

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Developing versatile methodologies to construct various nitrogen-containing heterocycles is a crucially significant part of contemporary organic chemistry. This review summarizes recent developments on the formation of nitrogen-containing heterocycles triggered by diaryliodonium salts. Diaryliodonium salts, as electrophilic arylating agents in the presence of catalytic copper salts, can react with nitriles to give N-arylnitrilium cations, which are highly reactive species. These species can efficiently react with nucleophiles, including C-, N- and O-nucleophiles, to give the corresponding products. This strategy is not only efficient and convenient, but also enables the synthesis of diverse nitrogen-containing heterocycles such as quinolines, quinazolines, and phenanthridines.1 Introduction2 Strategies and Mechanisms3 Cascade Annulations3.1 Cascade Annulation of Diaryliodoniums, Nitriles and C-Nucleophiles3.2 Cascade Annulation of Diaryliodoniums, Nitriles and N-Nucleophiles3.3 Cascade Annulation of Diaryliodoniums, Nitriles and O-Nucleophiles4 Summary and Outlook

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6

Slivka, Mikhailo y Mikhailo Onysko. "The Use of Electrophilic Cyclization for the Preparation of Condensed Heterocycles". Synthesis 53, n.º 19 (19 de mayo de 2021): 3497–512. http://dx.doi.org/10.1055/s-0040-1706036.

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AbstractCondensed heterocycles are well-known for their excellent biological effects and they are undeniably important compounds in organic chemistry. Electrophilic cyclization reactions are widely used for the synthesis of mono-heterocyclic compounds. This review highlights the utility of electrophilic cyclization reactions as an effective generic tool for the synthesis of various condensed heterocycles containing functional groups that are able to undergo further chemical transformations, such as nucleophilic substitution, elimination, re-cyclization, cleavage, etc. This review describes the reactions of unsaturated derivatives of different heterocycles with various electrophilic agents (halogens, arylsulfanyl chlorides, mineral acids) resulting in annulation of an additional partially saturated heterocycle. The electrophilic reaction conditions, plausible mechanisms and the use of such transformations in organic synthesis are also discussed. The review mainly focuses on research published since 2002 in order to establish the current state of the art in this area. 1 Introduction2 Electrophilic Cyclization Pathways Involving a Nitrogen Nucleophilic Center3 Electrophilic Cyclization Pathways Involving a Chalcogen Nucleophilic Center3.1 Sulfur Centers3.2 Oxygen Centers3.3 Selenium Centers4 Strategies and Mechanisms5 Conclusion

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7

Chandra, Swaroop, B. Suryaprasad, N. Ramanathan y K. Sundararajan. "Nitrogen as a pnicogen?: evidence for π-hole driven novel pnicogen bonding interactions in nitromethane–ammonia aggregates using matrix isolation infrared spectroscopy and ab initio computations". Physical Chemistry Chemical Physics 23, n.º 10 (2021): 6286–97. http://dx.doi.org/10.1039/d0cp06273a.

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8

Bhadra, Biswa Nath, Yong Su Baek, Cheol Ho Choi y Sung Hwa Jhung. "How neutral nitrogen-containing compounds are oxidized in oxidative-denitrogenation of liquid fuel with TiO2@carbon". Physical Chemistry Chemical Physics 23, n.º 14 (2021): 8368–74. http://dx.doi.org/10.1039/d1cp00633a.

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In oxidative denitrogenation of neutral nitrogen-containing compounds, it was found that oxygen firstly attacks the nitrogen atom, via electrophilic addition of an active oxygen atom; and oxygen on nitrogen moves to the nearby carbon atom because of the relative stability of the intermediates and products.

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9

Ageshina, Alexandra A., Gleb A. Chesnokov, Maxim A. Topchiy, Igor V. Alabugin, Mikhail S. Nechaev y Andrey F. Asachenko. "Making endo-cyclizations favorable again: a conceptually new synthetic approach to benzotriazoles via azide group directed lithiation/cyclization of 2-azidoaryl bromides". Organic & Biomolecular Chemistry 17, n.º 18 (2019): 4523–34. http://dx.doi.org/10.1039/c9ob00615j.

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10

Shen, Kun y Qiu Wang. "Copper-catalyzed diamination of unactivated alkenes with hydroxylamines". Chemical Science 6, n.º 7 (2015): 4279–83. http://dx.doi.org/10.1039/c5sc00897b.

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11

Varadwaj, Pradeep R., Arpita Varadwaj, Helder M. Marques y Koichi Yamashita. "The Nitrogen Bond, or the Nitrogen-Centered Pnictogen Bond: The Covalently Bound Nitrogen Atom in Molecular Entities and Crystals as a Pnictogen Bond Donor". Compounds 2, n.º 1 (15 de marzo de 2022): 80–110. http://dx.doi.org/10.3390/compounds2010007.

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The nitrogen bond in chemical systems occurs when there is evidence of a net attractive interaction between the electrophilic region associated with a covalently or coordinately bound nitrogen atom in a molecular entity and a nucleophile in another, or the same molecular entity. It is the first member of the family of pnictogen bonds formed by the first atom of the pnictogen family, Group 15, of the periodic table, and is an inter- or intra-molecular non-covalent interaction. In this featured review, we present several illustrative crystal structures deposited in the Cambridge Structure Database (CSD) and the Inorganic Crystal Structure Databases (ICSD) to demonstrate that imide nitrogen is not the only instance where nitrogen can act as an electrophilic agent. Analysis of a set of carefully chosen illustrative crystal systems shows that a covalently bound nitrogen atom in a variety of molecular entities features a σ-hole or even a π-hole, and these have the ability to sustain attractive engagements with negative sites to form inter- and/or intramolecular interactions that drive, or assist, the formation of a crystalline phase.

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12

Simonneau, Antoine, Pierre Garcia, Jean-Philippe Goddard, Virginie Mouriès-Mansuy, Max Malacria y Louis Fensterbank. "Combination of gold catalysis and Selectfluor for the synthesis of fluorinated nitrogen heterocycles". Beilstein Journal of Organic Chemistry 7 (7 de octubre de 2011): 1379–86. http://dx.doi.org/10.3762/bjoc.7.162.

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We herein report the synthesis of 3-fluoro-2-methylene-pyrrolidine (3a) and -piperidine (3b) from 1,5- and 1,6-aminoalkynes, respectively, using a combination of a gold-catalyzed hydroamination reaction followed by electrophilic trapping of an intermediate cyclic enamine by Selectfluor. Careful attention was paid to the elucidation of the mechanism and Selectfluor was suggested to play the double role of promoting the oxidation of gold(I) to a gold(III) active species and also the electrophilic fluorination of the enamine intermediates.

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13

Makarov, Anton S., Alexander A. Fadeev y Maxim G. Uchuskin. "Intramolecular iron-catalyzed transannulation of furans with O-acetyl oximes: synthesis of functionalized pyrroles". Organic Chemistry Frontiers 8, n.º 23 (2021): 6553–60. http://dx.doi.org/10.1039/d1qo01281a.

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14

Senthil Kumar Raju, Archana Settu, Archana Thiyagarajan, Divya Rama, Praveen Sekar y Shridharshini Kumar. "Synthetic approaches of medicinally important Schiff bases: An updated Review". World Journal of Advanced Research and Reviews 16, n.º 3 (30 de diciembre de 2022): 838–52. http://dx.doi.org/10.30574/wjarr.2022.16.3.1394.

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The Schiff base defined by an imine or azomethine (-CH= N-) group, is mostly synthesized by the condensation reaction of carbonyl compounds (Aldehyde or Ketone) with compounds consisting of amine moiety. Schiff bases are among the most chiefly used organic compounds, revealing a wide range of applications, such as electroluminescent effects, fluorescence properties, nonlinear optical and chemosensory properties. The typical Schiff bases are crystalline solids that are basic, although at least some of them combine with strong acids to generate insoluble salt. Schiff bases are widely used in the pharmaceutical, electronic, cosmetic and polymer industries. Schiff bases use various alpha-amino acids and aldehydes in acidic or basic conditions. Schiff bases form a new class of drugs that can strengthen the immune system and also be used in the treatment of various ailments. The C=N imine bond's electrophilic carbon and nucleophilic nitrogen offer great binding chances with many nucleophiles and electrophiles, which can be used to suppress specific diseases, enzymes or DNA replication. These Schiff bases are synthesized from various aldehydes or ketones and amines under stirring conditions, catalyst-free, reflux conditions, conventional methods, microwave irradiation and ultrasonic conditions. Thus, Schiff bases and their derivatives can be synthesized using various techniques and may be further used for enormous biological applications with potent effects.

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15

Senthil Kumar Raju, Archana Settu, Archana Thiyagarajan, Divya Rama, Praveen Sekar y Shridharshini Kumar. "Biological applications of Schiff bases: An overview". GSC Biological and Pharmaceutical Sciences 21, n.º 3 (30 de diciembre de 2022): 203–15. http://dx.doi.org/10.30574/gscbps.2022.21.3.0484.

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Schiff bases are the compounds containing the azomethine group (-HC=N-). They are formed by the condensation of ketones or aldehydes with a primary amine. Formation of Schiff base generally takes place under acid/base catalysis or with heat. The common Schiff bases are crystalline solids, which are basic but at least some form insoluble salts with strong acids. Schiff bases are used as intermediates for the synthesis of amino acids or as ligands for the preparation of metal complexes having a series of different structures. The electrophilic carbon and nucleophilic nitrogen in the C=N imine bond provide excellent binding opportunities with different nucleophiles and electrophiles thereby inhibiting targeted diseases, enzymes or DNA replication. These Schiff bases are synthesized from various aldehydes and amines under stirring conditions, catalyst-free, reflux conditions, microwave irradiation and ultrasonic conditions. These compounds serve a wide range of applications in pharmaceutical industries as well as chemical industries. There are a series of biological activities exhibited by these compounds which include antimicrobial, anti-inflammatory, antiviral and antioxidant activities. Apart from exhibiting medicinal properties, Schiff base compounds play an important role as ligands in coordination chemistry. Thus, Schiff bases and their derivatives may be further used for enormous biological applications with potent effects.

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16

Prieto, Alexis, Olivier Baudoin, Didier Bouyssi y Nuno Monteiro. "Electrophilic trifluoromethylation of carbonyl compounds and their nitrogen derivatives under copper catalysis". Chemical Communications 52, n.º 5 (2016): 869–81. http://dx.doi.org/10.1039/c5cc05954b.

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Recent advances in copper-catalyzed electrophilic trifluoromethylation of carbonyl compounds and their nitrogen derivatives are highlighted with particular focus on C–CF₃ bond forming reactions.

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17

Luan, Xinjun y Jingxun Yu. "Hydroxylamines as One-Atom Nitrogen Sources for Metal-Catalyzed Cycloadditions". Synthesis 53, n.º 08 (25 de enero de 2021): 1423–33. http://dx.doi.org/10.1055/s-0040-1706017.

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AbstractTransition-metal-catalyzed C–N bond formation is one of the most important pathways to synthesize N-heterocycles. Hydroxylamines can be transformed into a nucleophilic reagent to react with a carbon cation or coordinate with a transition metal; it can also become an electrophilic nitrogen source to react with arenes, alkenes, and alkynes. In this short review, the progress made on transition-metal-catalyzed cycloadditions with hydroxylamines as a nitrogen source is summarized.1 Introduction2 Cycloaddition To Form Aziridine Derivatives2.1 Intramolecular Cycloaddition To Form Aziridine Derivatives2.2 Intermolecular Cycloaddition To Form Aziridine Derivatives3 Cycloaddition To Form Indole Derivatives4 Cycloaddition To Form Other N-Heterocycles4.1 Aza-Heck-Type Amination Reactions4.2 Nitrene Insertion Amination Reactions4.3 Intramolecular Nucleophilic and Electrophilic Amination Reactions5 Conclusion and Outlook

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18

Jinan, Dilsha, Pinku Prasad Mondal, Anagha Veluthanath Nair y Basudev Sahoo. "O-Protected NH-free hydroxylamines: emerging electrophilic aminating reagents for organic synthesis". Chemical Communications 57, n.º 99 (2021): 13495–505. http://dx.doi.org/10.1039/d1cc05282a.

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O-Protected NH-free hydroxylamines have emerged as electrophilic aminating reagents for constructing nitrogen-enriched compounds with high regio-, and stereoselectivity in the unprotected form, through biocatalysis, organo-, and metal catalysis.

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19

Kang, Jun Yong y Hai Huang. "Triflic Anhydride (Tf2O)-Activated Transformations of Amides, Sulfoxides and Phosphorus Oxides via Nucleophilic Trapping". Synthesis 54, n.º 05 (27 de octubre de 2021): 1157–202. http://dx.doi.org/10.1055/a-1679-8205.

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AbstractTrifluoromethanesulfonic anhydride (Tf2O) is utilized as a strong electrophilic activator in a wide range of applications in synthetic organic chemistry, leading to the transient generation of a triflate intermediate. This versatile triflate intermediate undergoes nucleophilic trapping with diverse nucleophiles to yield novel compounds. In this review, we describe the features and applications of triflic anhydride in organic synthesis reported in the past decade, especially in amide, sulfoxide, and phosphorus oxide chemistry through electrophilic activation. A plausible mechanistic pathway for each important reaction is also discussed.1 Introduction2 Amide Chemistry2.1 Carbon Nucleophiles2.2 Hydrogen Nucleophiles2.3 Nitrogen Nucleophiles2.4 Oxygen and Sulfur Nucleophiles2.5 hosphorus Nucleophiles2.6 A Vilsmeier-Type Reagent2.7 Umpolung Reactivity in Amides3 Sulfoxide Chemistry3.1 Oxygen Nucleophiles3.2 Carbon Nucleophiles3.3 Nitrogen Nucleophiles3.4 Thionium Reagents4 Phosphorus Chemistry4.1 Hendrickson’s Reagent4.2 Diaryl Phosphine Oxides4.3 Phosphonates, Phosphates and Phosphinates5 Conclusion and Outlook

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20

Appiarius, Yannik, Tim Stauch, Enno Lork, Pascal Rusch, Nadja C. Bigall y Anne Staubitz. "From a 1,2-azaborinine to large BN-PAHs via electrophilic cyclization: synthesis, characterization and promising optical properties". Organic Chemistry Frontiers 8, n.º 1 (2021): 10–17. http://dx.doi.org/10.1039/d0qo00723d.

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A synthetic approach towards boron-nitrogen substituted polycyclic aromatic hydrocarbons (BN-PAHs) via electrophilic cyclization is described and it is shown that the variation of the rings' connectivity may tune the emission wavelengths effectively.

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21

Ren, Yun-Lai, Huantao Shang, Jianji Wang, Xinzhe Tian, Shuang Zhao, Qian Wang y Fuwei Li. "Nitrogen Dioxide-Catalyzed Electrophilic Iodination of Arenes". Advanced Synthesis & Catalysis 355, n.º 17 (8 de noviembre de 2013): 3437–42. http://dx.doi.org/10.1002/adsc.201300581.

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22

Ramirez-Balderrama, Kathy, Erasmo Orrantia-Borunda y Norma Flores-Holguin. "Calculation of global and local reactivity descriptors of carbodiimides, a DFT study". Journal of Theoretical and Computational Chemistry 16, n.º 03 (2 de marzo de 2017): 1750019. http://dx.doi.org/10.1142/s0219633617500195.

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Carbodiimides have been widely used for different purposes, such as an intermediary to form peptides bonds and esters, which have generated industrial, organic and biological applications. Diisoproylcarbodiimide (DIC), (3-(dimethylamino) propyl)ethylcarbodiimide (EDC) and N,N′-dicyclohexylcarbodiimide (DCC) are the most common carbodiimides, however, there exist other carbodiimides that are not normally used. Twelve carbodiimides including the above mentioned were chosen to study their chemical reactivity as well as their nucleophilic and electrophilic attack sites. Geometry optimization in gas and solution phases was obtained using Density Functional Theory (DFT) through B3LYP with 6-31G(d) and 6-311[Formula: see text]G(d,p) level. Global and local reactivity descriptors were calculated and analyzed such as chemical hardness, ionization potential, electron affinity, Fukui functions, dual descriptor and hypersoftness. The results obtained for geometrical parameters do not have significant differences for gas and solution phase. The introduction of diffuse functions has great impact in electron affinity, modifying notably the values of reactivity descriptors, but didn’t show qualitative differences, since the results found for both basis set calculations show that Cyanamide or CD1 is the most stable and CD11 present greater reactivity of all studied molecules. Also, the hypersoftness results obtained with 6-31G(d) are in agreement with the general affirmation that carbodiimides are easily attacked by nucleophiles and electrophiles in the central carbon–nitrogen double bond.

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23

Zmijewski, J. W., A. Landar, N. Watanabe, D. A. Dickinson, N. Noguchi y V. M. Darley-Usmar. "Cell signalling by oxidized lipids and the role of reactive oxygen species in the endothelium". Biochemical Society Transactions 33, n.º 6 (26 de octubre de 2005): 1385–89. http://dx.doi.org/10.1042/bst0331385.

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The controlled formation of ROS (reactive oxygen species) and RNS (reactive nitrogen species) is now known to be critical in cellular redox signalling. As with the more familiar phosphorylation-dependent signal transduction pathways, control of protein function is mediated by the post-translational modification at specific amino acid residues, notably thiols. Two important classes of oxidant-derived signalling molecules are the lipid oxidation products, including those with electrophilic reactive centres, and decomposition products such as lysoPC (lysophosphatidylcholine). The mechanisms can be direct in the case of electrophiles, as they can modify signalling proteins by post-translational modification of thiols. In the case of lysoPC, it appears that secondary generation of ROS/RNS, dependent on intracellular calcium fluxes, can cause the secondary induction of H2O2 in the cell. In either case, the intracellular source of ROS/RNS has not been defined. In this respect, the mitochondrion is particularly interesting since it is now becoming apparent that the formation of superoxide from the respiratory chain can play an important role in cell signalling, and oxidized lipids can stimulate ROS formation from an undefined source. In this short overview, we describe recent experiments that suggest that the cell signalling mediated by lipid oxidation products involves their interaction with mitochondria. The implications of these results for our understanding of adaptation and the response to stress in cardiovascular disease are discussed.

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24

Li, Jiaquan, Hongqi Sun, Shaobin Wang, Yu Dong y Shaomin Liu. "Selective oxidation of alcohols by graphene-like carbon with electrophilic oxygen and integrated pyridinic nitrogen active sites". Nanoscale 13, n.º 30 (2021): 12979–90. http://dx.doi.org/10.1039/d1nr03157k.

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N-Doped graphene-like carbon was prepared via a metal-free method. Electrophilic oxygen and nitrogen species functioned as dual active sites to activate peroxymonosulfate to convert alcohol into aldehyde or ketone by radical and non-radical routes.

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25

Luo, Xuewei, Sheng Wang y Chanjuan Xi. "Cp2TiCl2-catalyzed highly regioselective hydroamination of styrenes with hydroxylamines". Organic Chemistry Frontiers 5, n.º 7 (2018): 1184–87. http://dx.doi.org/10.1039/c7qo01068k.

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An efficient Cp₂TiCl₂-catalyzed one-pot two-step hydroamination procedure that allows the direct formation of tertiary amines from styrenes and an electrophilic nitrogen source has been reported with high regioselectivity.

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26

Li, Huimin, Lihao Liao y Xiaodan Zhao. "Organoselenium-Catalyzed Aza-Wacker Reactions: Efficient Access to Isoquinolinium Imides and an Isoquinoline N-Oxide". Synlett 30, n.º 14 (28 de junio de 2019): 1688–92. http://dx.doi.org/10.1055/s-0039-1690103.

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An efficient approach for the organoselenium-catalyzed aza-Wacker reaction of olefinic hydrazones and an oxime to form isoquinolinium imides and an isoquinoline N-oxide is developed. This transformation involves a direct intramolecular C–H amination using hydrazones and an oxime as imine-type nitrogen sources. This work not only provides a new approach for the construction of isoquinoline derivatives, but also expands the scope of nitrogen sources in electrophilic selenium catalysis.

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27

Harjivan, Shrika G., Pedro F. Pinheiro, Inês L. Martins, Ana L. Godinho, Riccardo Wanke, Pedro P. Santos, Sofia A. Pereira, Frederick A. Beland, M. Matilde Marques y Alexandra M. M. Antunes. "Quinoid derivatives of the nevirapine metabolites 2-hydroxy- and 3-hydroxy-nevirapine: activation pathway to amino acid adducts". Toxicology Research 4, n.º 6 (2015): 1565–77. http://dx.doi.org/10.1039/c5tx00176e.

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28

Comparini, Lucrezia Margherita y Mauro Pineschi. "Recent Progresses in the Catalytic Stereoselective Dearomatization of Pyridines". Molecules 28, n.º 17 (22 de agosto de 2023): 6186. http://dx.doi.org/10.3390/molecules28176186.

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1,2- and 1,4-dihydropyridines and N-substituted 2-pyridones are very important structural motifs due to their synthetic versatility and vast presence in a variety of alkaloids and bioactive molecules. In this article, we gather and summarize the catalytic and stereoselective synthesis of partially hydrogenated pyridines and pyridones via the dearomative reactions of pyridine derivatives up to mid-2023. The material is fundamentally organized according to the type of reactivity (electrophilic/nucleophilic) of the pyridine nucleus. The material is further sub-divided taking into account the nucleophilic species when dealing with electrophilic pyridines and considering the reactivity manifold of pyridine derivatives behaving as nucleophiles at the nitrogen site. The latter more recent approach allows for an unconventional entry to chiral N-substituted 2- and 4-pyridones in non-racemic form.

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29

Frontier, Alison J., Shukree Abdul-Rashed y Connor Holt. "Alkynyl Prins and Alkynyl Aza-Prins Annulations: Scope and Synthetic Applications". Synthesis 52, n.º 14 (9 de abril de 2020): 1991–2007. http://dx.doi.org/10.1055/s-0039-1690869.

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This review focuses on alkynyl Prins and alkynyl aza-Prins cyclization processes, which involve intramolecular coupling of an alkyne with either an oxocarbenium or iminium electrophile. The oxocarbenium or iminium species can be generated through condensation- or elimination-type processes, to achieve an overall bimolecular annulation that enables the synthesis of both oxygen- and nitrogen-containing saturated heterocycles with different ring sizes and substitution patterns. Also discussed are cascade processes in which alkynyl Prins heterocyclic adducts react to trigger subsequent pericyclic reactions, including [4+2] cycloadditions and Nazarov electrocyclizations, to rapidly construct complex small molecules. Finally, examples of the use of alkynyl Prins and alkynyl aza-Prins reactions in the synthesis of natural products are described. The review covers the literature through the end of 2019.1 Introduction1.1 Alkyne-Carbonyl Coupling Pathways1.2 Coupling/Cyclization Cascades Using the Alkynyl Prins Reaction2 Alkynyl Prins Annulation (Oxocarbenium Electrophiles)2.1 Early Work2.2 Halide as Terminal Nucleophile2.3 Oxygen as Terminal Nucleophile2.4 Arene as Terminal Nucleophile (Intermolecular)2.5 Arene Terminal Nucleophile (Intramolecular)2.6 Cyclizations Terminated by Elimination3 Synthetic Utility of Alkynyl Prins Annulation3.1 Alkynyl Prins-Mediated Synthesis of Dienes for a [4+2] Cyclo- addition-Oxidation Sequence3.2 Alkynyl Prins Cyclization Adducts as Nazarov Cyclization Precursors3.3 Alkynyl Prins Cyclization in Natural Product Synthesis4 Alkynyl Aza-Prins Annulation4.1 Iminium Electrophiles4.2 Activated Iminium Electrophiles5 Alkynyl Aza-Prins Cyclizations in Natural Product Synthesis6 Summary and Outlook

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30

Rakowski DuBois, M., L. D. Vasquez, R. F. Ciancanelli y B. C. Noll. "Electrophilic Substitution of Nitrogen Heterocycles by Molybdenum Sulfide Complexes". Organometallics 19, n.º 18 (septiembre de 2000): 3507–15. http://dx.doi.org/10.1021/om000218u.

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31

Ren, Yun-Lai, Huantao Shang, Jianji Wang, Xinzhe Tian, Shuang Zhao, Qian Wang y Fuwei Li. "ChemInform Abstract: Nitrogen Dioxide-Catalyzed Electrophilic Iodination of Arenes." ChemInform 45, n.º 19 (23 de abril de 2014): no. http://dx.doi.org/10.1002/chin.201419057.

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32

Sarkar, Sounak, Mysore S. Pavan y T. N. Guru Row. "Experimental validation of ‘pnicogen bonding’ in nitrogen by charge density analysis". Physical Chemistry Chemical Physics 17, n.º 4 (2015): 2330–34. http://dx.doi.org/10.1039/c4cp04690k.

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33

Bédé, Lucie A., Mawa Koné, Guy R. M. Koné, Simplice C. S. Ouattara, Lamoussa Ouattara y El Hadji S. Bamba. "Tautomeric Equilibrium Modeling: Stability and Reactivity of Benzothiazole and Derivatives". International Journal of Chemistry 11, n.º 1 (29 de abril de 2019): 84. http://dx.doi.org/10.5539/ijc.v11n1p84.

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Benzothiazoles are organic compounds with multiple biological activities. Due to their biological interests, these are synthesized on a large scale at the industrial level and used in various fields. Their release into waters causes environmental problems which leads to public health problems. Finding solution which can help for their degradation become necessary. That is the reason why a theoretical study of the reactivity of five benzothiazole derivatives has been initiated in order to understand some aspect of their biodegradation. The calculations were carried out in gaseous and aqueous phase with B3LYP functional associated with bases 6-311G(d) and 6-31+G(d). The results revealed that the thione tautomer of the MBT derivative is more stable than the thiol form. These results are in agreement with previous experimental work which showed that the thiones forms in MBT metal complexes are the most stable. Moreover, the study of the reactivity based on the computation of the global indices of reactivity reveals that the benzothiazoles BT, OBT and MBT are the most reactive. The most electrophilic is BT and the least electrophilic is MTBT. In addition, the thermodynamic parameters and the energy barriers predict a possibility of coexistence of tautomers ol and one of OBT derivative. Fukui dual descriptors have shown that the carbon C2 of BT is the most electrophilic. In substituted derivatives, it is the C6 carbon that is the most electrophilic. N3 nitrogen remains the most nucleophilic site in all the studied molecules.

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34

Lu, Mengsi, Oliver Allemann, Jun Xu, Anthony Linden, Kim K. Baldridge y Jay S. Siegel. "Peraryl-X-onium ions of nitrogen and oxygen". Organic Chemistry Frontiers 6, n.º 15 (2019): 2640–46. http://dx.doi.org/10.1039/c9qo00633h.

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Carbon fluorine bond activation produces phenyl cations that are effective electrophiles for a new synthesis of tetraarylammonium and triaryloxonium ions. In parallel with diazonium salt decomposition a robust and general method to these underrepresented cations is demonstrated in this work.

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35

Motornov, Vladimir y Petr Beier. "NH-1,2,3-triazoles as versatile building blocks in denitrogenative transformations". RSC Advances 13, n.º 49 (2023): 34646–51. http://dx.doi.org/10.1039/d3ra06045d.

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The utilization of NH-1,2,3-triazoles as easily accessible building blocks in denitrogenative ring cleavage transformations with electrophiles to provide multifunctionalized nitrogen heterocycles and N-alkenyl compounds is reviewed.

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36

Murai, Toshiaki. "Thioamide dianions derived from N-arylmethyl thioamides: Generation and application as carbon nucleophiles adjacent to the nitrogen atom". Pure and Applied Chemistry 82, n.º 3 (18 de febrero de 2010): 541–54. http://dx.doi.org/10.1351/pac-con-09-08-04.

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This review illustrates the ready availability of thioamide dianions and their versatility as carbon nucleophiles adjacent to the nitrogen atom. The products derived from the addition of thioamide dianions to a range of electrophiles can participate in a cyclization reaction to form nitrogen-containing heterocycles. The electronic properties of thioamide dianions are also considered.

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37

Das, Tamal Kanti y Akkattu T. Biju. "Imines as acceptors and donors in N-heterocyclic carbene (NHC) organocatalysis". Chemical Communications 56, n.º 61 (2020): 8537–52. http://dx.doi.org/10.1039/d0cc03290e.

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The application of imines as electrophiles (acceptors) or as a source of nucleophiles (donors) in N-heterocyclic carbene (NHC) catalysis for the synthesis of various nitrogen heterocycles and functionalized amines is presented.

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38

Joost, Maximilian, Wesley J. Transue y Christopher C. Cummins. "Diazomethane umpolung atop anthracene: an electrophilic methylene transfer reagent". Chemical Science 9, n.º 6 (2018): 1540–43. http://dx.doi.org/10.1039/c7sc04506a.

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39

Li, Juan, Ning Wang, Wen-Tao Liu, Hong-Lin Ding, Yue An y Cheng-Wei Lü. "A revisit to the Gattermann reaction: interesting synthesis of nitrogen heterocyclic aromatic halides and their fluorescence properties". New J. Chem. 41, n.º 20 (2017): 12225–30. http://dx.doi.org/10.1039/c7nj02672b.

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The Gattermann reaction and an electrophilic substitution reaction, which were conducted in a one-pot reaction, are reported, and four aromatic dihalides of similar structure were obtained. 2-Chloro-5-(3-chloro-4-methoxy-phenyl)-1,3,4-thiadiazole was applied as a highly efficient fluorescence sensor for the detection of TNP.

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40

Jarvo, Elizabeth y Timothy Barker. "Developments in Transition-Metal-Catalyzed Reactions Using Electrophilic Nitrogen Sources". Synthesis 2011, n.º 24 (27 de octubre de 2011): 3954–64. http://dx.doi.org/10.1055/s-0031-1289581.

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41

Qiang, Peirong, Zuobang Sun, Bai Xue y Fan Zhang. "π-Extended Ladder-Type Conjugated Polymers via BN-Annulation". Organic Materials 03, n.º 02 (abril de 2021): 221–27. http://dx.doi.org/10.1055/s-0041-1727181.

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Two kinds of ladder-type conjugated polymers were concisely synthesized by the formation of single-stranded conjugated polymers via Stille cross-couplings, followed by nitrogen-directed electrophilic borylations at electron-rich aromatic rings. The resulting BN-annulated polymers show good film-forming behaviors and high air and thermal stability. Their structurally shape-persistent rigid backbones render them with π-extended conjugation, allowing for efficient light harvesting in the low-energy regions, and emitting strong fluorescence with narrow emission widths.

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42

Chaudhari, Raju y Sahebrao Rindhe. "Synthesis and antimicrobial activities of novel n-substituted 8-(1-alkyl/alkylsulphonyl/alkoxycarbonyl-benzimidazol-2-ylmethoxy)-5-chloroquinolines". Journal of the Serbian Chemical Society 76, n.º 9 (2011): 1199–206. http://dx.doi.org/10.2298/jsc100817105c.

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Herein the synthesis of a series of novel 8-(1- alkyl/alkylsulphonyl/alkoxycarbonyl-benzimidazol-2-ylmethoxy)-5- chloroquinoline derivatives is reported. These derivatives were prepared by the condensation of o-phenylenediamine with [(5-chloroquinolin-8- yl)oxy]acetic acid, followed by substitution at nitrogen with different electrophilic reagents in presence of an appropriate base to give a series of nitrogen heterocycles containing the benzimidazole and quinoline nuclei. The structures of the compounds were confirmed based on 1H-NMR, 13CNMR, IR and mass spectral data. Almost all the compounds exhibited promising antibacterial activity against Salmonella typhimurium and Staphylococcus aureus. Some of the compounds showed good antifungal activities against Aspergillus niger but the antifungal activities against Candida albicans were disappointing.

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43

Ranjith, Jala y Hyun-Joon Ha. "Synthetic Applications of Aziridinium Ions". Molecules 26, n.º 6 (22 de marzo de 2021): 1774. http://dx.doi.org/10.3390/molecules26061774.

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Nonactivated aziridine with an electron-donating group at the ring nitrogen should be activated to an aziridinium ion prior to being converted to cyclic and acyclic nitrogen-containing molecules. This review describes ways to generate aziridinium ions and their utilization for synthetic purposes. Specifically, the intra- and intermolecular formation of aziridinium ions with proper electrophiles are classified, and their regio- and stereoselective transformations with nucleophiles are described on the basis of recent developments.

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44

Mueller, Louis G., Allen Chao, Embarek AlWedi y Fraser F. Fleming. "One-step synthesis of imidazoles from Asmic (anisylsulfanylmethyl isocyanide)". Beilstein Journal of Organic Chemistry 17 (24 de junio de 2021): 1499–502. http://dx.doi.org/10.3762/bjoc.17.106.

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Substituted imidazoles are readily prepared by condensing the versatile isocyanide Asmic, anisylsulfanylmethylisocyanide, with nitrogenous π-electrophiles. Deprotonating Asmic with lithium hexamethyldisilazide effectively generates a potent nucleophile that efficiently intercepts nitrile and imine electrophiles to afford imidazoles. In situ cyclization to the imidazole is promoted by the conjugate acid, hexamethyldisilazane, which facilitates the requisite series of proton transfers. The rapid formation of imidazoles and the interchange of the anisylsulfanyl for hydrogen with Raney nickel make the method a valuable route to mono- and disubstituted imidazoles.

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45

Reisenbauer, Julia C., Ori Green, Allegra Franchino, Patrick Finkelstein y Bill Morandi. "Late-stage diversification of indole skeletons through nitrogen atom insertion". Science 377, n.º 6610 (2 de septiembre de 2022): 1104–9. http://dx.doi.org/10.1126/science.add1383.

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Compared with peripheral late-stage transformations mainly focusing on carbon–hydrogen functionalizations, reliable strategies to directly edit the core skeleton of pharmaceutical lead compounds still remain scarce despite the recent flurry of activity in this area. Herein, we report the skeletal editing of indoles through nitrogen atom insertion, accessing the corresponding quinazoline or quinoxaline bioisosteres by trapping of an electrophilic nitrene species generated from ammonium carbamate and hypervalent iodine. This reactivity relies on the strategic use of a silyl group as a labile protecting group that can facilitate subsequent product release. The utility of this highly functional group-compatible methodology in the context of late-stage skeletal editing of several commercial drugs is demonstrated.

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46

Beaumier, Evan P., Brennan S. Billow, Amrendra K. Singh, Shannon M. Biros y Aaron L. Odom. "A complex with nitrogen single, double, and triple bonds to the same chromium atom: synthesis, structure, and reactivity". Chemical Science 7, n.º 4 (2016): 2532–36. http://dx.doi.org/10.1039/c5sc04608d.

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A complex with single, double and triple bonds between nitrogen and the same metal center has been synthesized, [NCr(NPh)(NPrⁱ₂)₂]⁻. The complex shows differential activity, with some electrophiles attacking the imido and others the nitrido.

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47

Schiemenza, Günter Paulus, Simon Pörksen, Paulina M. Dominiak y Krzysztof Wozniak. "peri-Interactions in Naphthalenes, 6 [1]. On Hypercoordination of Phosphorus in 8-Dialkylamino-naphth-1-yl Phosphonium Salts". Zeitschrift für Naturforschung B 57, n.º 1 (1 de enero de 2002): 8–18. http://dx.doi.org/10.1515/znb-2002-0102.

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Under favourable conditions, the phosphorus centres in tetraorganophosphonium cations are sufficiently electrophilic to become hypercoordinate by reaction with strong nucleophiles. However, as a peri substituent at the naphthalene system, such a centre proved to be unable to induce the nitrogen of a peri-bound dialkylamino group to bond formation. The distortion of the naphthalene skeleton revealed by X-ray structure determination of four 8-dialkylaminonaphth- 1-yl phosphonium salts does not exhibit the criteria of N-P bond formation but rather those of intersubstituent repulsion.

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48

Pabel, Jörg, Elmar Wadenstorfer y Klaus T. Wanner. "Asymmetric Synthesis of Pyrido[1,2-c]pyrimidinones". Zeitschrift für Naturforschung B 64, n.º 6 (1 de junio de 2009): 653–61. http://dx.doi.org/10.1515/znb-2009-0610.

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“Asymmetric Electrophilic α-Amidoalkylation” reactions with a chiral alkylaminocarbonyl unit as chiral auxiliary are used for the stereoselective synthesis of 2-substituted piperidine derivatives. Intramolecular condensation of the nitrogen of the aminocarbonyl group with the keto function present in the newly introduced side chain of the amidoalkylation products results in the formation of hexahydropyrido[1,2-c]pyrimidinones. After reduction and removal of the N-alkyl moiety of the chiral auxiliary the target compounds, enantiopure octahydro-1H-pyrido[1,2-c]pyrimidin-1-ones, are obtained.

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49

Fujioka, Hiromichi, Yasuyuki Kita, Ozora Kubo, Kento Senami, Kazuhisa Okamoto y Takashi Okitsu. "Organic Chemistry Using Weakly Electrophilic Salts: The Reaction with Nitrogen Nucleophiles". HETEROCYCLES 79, n.º 1 (2009): 1113. http://dx.doi.org/10.3987/com-08-s(d)69.

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50

Chambers, Richard D., Alan M. Kenwright, Mandy Parsons, Graham Sandford y John S. Moilliet. "Elemental fluorine. Part 14.1 Electrophilic fluorination and nitrogen functionalisation of hydrocarbons". Journal of the Chemical Society, Perkin Transactions 1, n.º 19 (3 de septiembre de 2002): 2190–97. http://dx.doi.org/10.1039/b204776b.

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