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Articoli di riviste sul tema "Imines"

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Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 28 luglio 2024

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1

Svete, Jurij, Uroš Grošelj, Franc Požgan e Bogdan Štefane. "Copper-Catalyzed Azomethine Imine–Alkyne Cycloadditions (CuAIAC)". Synthesis 50, n. 23 (5 ottobre 2018): 4501–24. http://dx.doi.org/10.1055/s-0037-1610284.

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Abstract (sommario):

Although the first example of copper-catalyzed azomethine imine–alkyne cycloaddition (CuAIAC) was published only a year after the seminal papers of Meldal and Sharpless on Cu-catalyzed azide–alkyne cycloaddition (CuAAC), the CuAIAC reaction has remained overlooked by the synthetic community for almost a decade. Since 2010, however, CuAIAC reaction started to emerge as a promising supplement to the well-known CuAAC reaction. The present review surveys primarily the literature on CuAIAC reaction since 2003. Beside this, azomethine imine–alkyne cycloadditions catalyzed by other metals, selected examples of metal-free reactions, and related [3+3] and [3+4] cycloadditions of azomethine imines are presented. All these experimental data indicate the viability of CuAIAC in organic synthesis and the applicability in ‘click’ chemistry.1 Introduction2 Reactions with Acyclic Azomethine Imines3 Reactions with C,N-Cyclic Azomethine Imines4 Reactions with N,N-Cyclic Azomethine Imines5 Reactions with C,N,N-Cyclic Azomethine Imines6 The Mechanism of the CuAIAC Reaction7 Conclusions and Outlook

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2

Wulff, William, Xin Zhang e Yijing Dai. "The Acceleration of the Rearrangement of α-Hydroxy Aldimines by Lewis or Brønsted Acids". Synlett 29, n. 15 (28 agosto 2018): 2015–18. http://dx.doi.org/10.1055/s-0037-1610262.

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An efficient method was developed for the synthesis of α-amino ketones from α-hydroxy imines. The reaction occurs through an α-iminol rearrangement involving the migration of a substituent of the carbinol carbon to the imine carbon. The optimal catalysts were found to be silica gel or montmorillonite K 10, which effected migration of a variety of aryl and alkyl substituents in high yields. The rearrangement can also be carried out on imines generated in situ from aldehydes and amines in essentially the same yields as those from the preformed imines.

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3

Gonciarz, Agnieszka, Robert Pich, Krzysztof Artur Bogdanowicz, Beata Jewloszewicz, Wojciech Przybył, Karolina Dysz, Agnieszka Dylong et al. "UV–Vis Absorption Properties of New Aromatic Imines and Their Compositions with Poly({4,8-bis[(2-Ethylhexyl)oxy]Benzo[1,2-b:4,5-b′]Dithiophene-2,6-diyl}{3-Fluoro-2-[(2-Ethylhexyl)Carbonyl]Thieno[3,4-b]Thiophenediyl})". Materials 12, n. 24 (13 dicembre 2019): 4191. http://dx.doi.org/10.3390/ma12244191.

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In this paper, four new aromatic imines containing at least one thiazole-based heterocycle were analyzed in detail by UV–Vis spectroscopy, taking into consideration their chemical structures and interactions with PTB7, a known polymeric electron donor widely used in bulk heterojunction organic solar cells. It is demonstrated that the absorption spectra of the investigated active compositions can be modified not only by changing the chemical structure of imine, but also via formulations with PTB7. For all investigated imines and PTB7:imine compositions, calibration curves were obtained in order to find the optimum concentration in the composition with PTB7 for expansion and optimization of absorption spectra. All imines and PTB7:imine compositions were investigated in 1,2-dichlorobenzene by UV–Vis spectroscopy in various concentrations, monitoring the changes in the π–π* and n–π* transitions. With increasing imine concentrations, we did not observe changes in absorption maxima, while with increasing imine concentrations, a hypochromic effect was observed. Finally, we could conclude that all investigated compositions exhibited wide absorptions of up to 800 nm and isosbestic points in the range of 440–540 nm, confirming changes in the macromolecular organization of the tested compounds. The theoretical calculations of their vibration spectra (FTIR) and LUMO–HOMO levels by Density Functional Theory (DFT) methods are also provided. Finally, IR thermal images were measured for organic devices based on imines and the imine:PTB7 composite.

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4

Mendes, Joseane A., Paulo R. R. Costa, Miguel Yus, Francisco Foubelo e Camilla D. Buarque. "N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles". Beilstein Journal of Organic Chemistry 17 (12 maggio 2021): 1096–140. http://dx.doi.org/10.3762/bjoc.17.86.

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Abstract (sommario):

The synthesis of nitrogen-containing heterocycles, including natural alkaloids and other compounds presenting different types of biological activities have proved to be successful employing chiral sulfinyl imines derived from tert-butanesulfinamide. These imines are versatile chiral auxiliaries and have been extensively used as eletrophiles in a wide range of reactions. The electron-withdrawing sulfinyl group facilitates the nucleophilic addition of organometallic compounds to the iminic carbon with high diastereoisomeric excess and the free amines obtained after an easy removal of the tert-butanesulfinyl group can be transformed into enantioenriched nitrogen-containing heterocycles. The goal of this review is to the highlight enantioselective syntheses of heterocycles involving the use of chiral N-tert-butanesulfinyl imines as reaction intermediates, including the synthesis of several natural products. The synthesis of nitrogen-containing heterocycles in which the nitrogen atom is not provided by the chiral imine will not be considered in this review. The sections are organized according to the size of the heterocycles. The present work will comprehensively cover the most pertinent contributions to this research area from 2012 to 2020. We regret in advance that some contributions are excluded in order to maintain a concise format.

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5

Garrido-Castro, Alberto F., M. Carmen Maestro e José Alemán. "α-Functionalization of Imines via Visible Light Photoredox Catalysis". Catalysts 10, n. 5 (19 maggio 2020): 562. http://dx.doi.org/10.3390/catal10050562.

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Abstract (sommario):

The innate electrophilicity of imine building blocks has been exploited in organic synthetic chemistry for decades. Inspired by the resurgence in photocatalysis, imine reactivity has now been redesigned through the generation of unconventional and versatile radical intermediates under mild reaction conditions. While novel photocatalytic approaches have broadened the range and applicability of conventional radical additions to imine acceptors, the possibility to use these imines as latent nucleophiles via single-electron reduction has also been uncovered. Thus, multiple research programs have converged on this issue, delivering creative and practical strategies to achieve racemic and asymmetric α-functionalizations of imines under visible light photoredox catalysis.

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6

Nugent, Thomas C., Richard Vaughan Williams, Andrei Dragan, Alejandro Alvarado Méndez e Andrei V. Iosub. "An investigation of the observed, but counter-intuitive, stereoselectivity noted during chiral amine synthesis via N-chiral-ketimines". Beilstein Journal of Organic Chemistry 9 (15 ottobre 2013): 2103–12. http://dx.doi.org/10.3762/bjoc.9.247.

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The default explanation for good to high diastereomeric excess when reducing N-chiral imines possessing only mediocre cis/trans-imine ratios (>15% cis-imine) has invariably been in situ cis-to-trans isomerization before reduction; but until now no study unequivocally supported this conclusion. The present study co-examines an alternative hypothesis, namely that some classes of cis-imines may hold conformations that erode the inherent facial bias of the chiral auxiliary, providing more of the trans-imine reduction product than would otherwise be expected. The ensuing experimental and computational (DFT) results favor the former, pre-existing, explanation.

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7

Rawaa Daoud Sulaiman e Zaheda Ahmed Najim. "The Effect of Temperature and Thermodynamic Parameters on the Ionization Constants of Some Imines Derived from Vanillin with substituted aniline". Tikrit Journal of Pure Science 27, n. 4 (28 novembre 2022): 31–38. http://dx.doi.org/10.25130/tjps.v27i4.30.

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This work presents a method for the preparation of imine compounds including Schiff bases derived from vanillin with aniline, o-nitroaniline, o-tolidene and o-chloroaniline. Compounds' structures of the prepared compounds were confirmed by physical methods like melting point, infrared spectroscopy (IR), electronic spectroscopy (U.V), and nuclear magnetic resonance spectroscopy (NMR). The ionization constants of the imine nitrogen proton Ka1 and the phenol hydroxyl group proton Ka2 were determined using the spectrometric titration method at five temperatures including 293,298,303,308 and 313K in a buffer solution medium. The thermodynamic of ionization for imines confirm that ionization reactions in these imines are accompanied by an increase of parameters ∆Gº and ∆Hº. These mean that ionization reactions in these imines are non-spontaneous and endothermic respectively. ∆Sº values of ionization reactions estimated have a negative and a positive signs.

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8

An, Ran, Mengbi Guo, Yingbo Zang, Hang Xu, Zhuang Hou e Chun Guo. "Recent Advances in Synthesis of Benzazoles via Imines". Current Organic Chemistry 24, n. 17 (12 novembre 2020): 1897–942. http://dx.doi.org/10.2174/1385272824999200818180845.

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Imines, versatile intermediates for organic synthesis, can be exploited for the preparation of diverse classes of biologically active benzazoles. Because of the special characteristics of the C=N bond, imines can be simultaneously used in the synthesis of 1,3-benzazoles and 1,2-benzazoles. With the development of imine synthesis, a variety of novel cascade reactions for benzazole synthesis have been reported in the last decade. Therefore, there is a strong need to elucidate the recent progress in the formation of various classes of benzazoles, including benzimidazoles, benzoxazoles, benzothiazoles, indazoles, and benzisoxazoles, via imines obtained by condensation reactions or oxidative/ redox coupling reactions

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9

Freese, Tyll, Jan C. Namyslo, Martin Nieger e Andreas Schmidt. "Sulfur, mercury, and boron adducts of sydnone imine derived anionic N-heterocyclic carbenes". RSC Advances 9, n. 9 (2019): 4781–88. http://dx.doi.org/10.1039/c9ra00294d.

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The sydnone imines (5-benzoylimino)-3-(2-methoxyphenyl)-sydnone imine and molsidomine were deprotonated at C4 to give sydnone imine anions which can be represented as anionic N-heterocyclic carbenes, respectively.

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10

Zhang, Hanmo, E. Ben Hay, Stephen J. Geib e Dennis P. Curran. "Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides". Beilstein Journal of Organic Chemistry 11 (17 settembre 2015): 1649–55. http://dx.doi.org/10.3762/bjoc.11.181.

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Two new fates of imine intermediates formed on radical cyclizations of ene-sulfonamides have been identified, reduction and hydration/fragmentation. Tin hydride-mediated cyclizations of 2-halo-N-(3-methyl-N-sulfonylindole)anilines provide spiro[indoline-3,3'-indolones] or spiro-3,3'-biindolines (derived from imine reduction), depending on the indole C2 substituent. Cyclizations of 2-haloanilide derivatives of 3-carboxy-N-sulfonyl-2,3-dihydropyrroles also presumably form spiro-imines as primary products. However, the lactam carbonyl group facilitates the ring-opening of these cyclic imines by a new pathway of hydration and retro-Claisen-type reaction, providing rearranged 2-(2'-formamidoethyl)oxindoles.

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11

Meng, Qingxi, Fen Wang e Ming Li. "Bisoxazoline–copper(I)-catalyzed aziridination of diazoacetate with imines — A DFT study". Canadian Journal of Chemistry 88, n. 10 (ottobre 2010): 981–90. http://dx.doi.org/10.1139/v10-099.

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Density functional theory (DFT) has been used to study bisoxazoline–copper(I)-catalyzed aziridination of diazoacetate with syn-imines or anti-imines. All the intermediates and transition states were optimized completely at the B3LYP/6-31G(d) level. Calculation results confirm that Cu(I)-catalyzed aziridination goes mainly through the catalyst–diazoacetate complex (M1), the copper(I)–carbene intermediate (M2), the copper–carbene–imine complex (M3), and the catalyst–aziridine carboxylate complex (M4). For syn-imines, the reaction mode I (C3–N5 bond attacking the Cu–C1 bond of M2) is more dominant than the reaction mode II (C3–N5 bond attacking the carbene–carbon C1 of M2), and the attack from the si-surface of M2 is prior to the re-surface. For anti-imines, the reaction modes and attacks from the si- or re-surface coexist. The reactivity of syn-imines is stronger than anti-imines. The favorable reaction channel is CA2 → M1b → TS1b → M2 → syn-TS2b → syn-M3b → syn-TS3b → syn-M4b → syn-P2. The dominant product theoretically predicted is of (S,S)-chirality. On the whole, the solvent effect decreases the free energies of the species.

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12

Baig, Fayaz, Rajni Kant, Vivek K. Gupta e Madhushree Sarkar. "Effects of non covalent interactions in light emitting properties of bis-pyridyl-alkyl-di-imines". RSC Advances 5, n. 63 (2015): 51220–32. http://dx.doi.org/10.1039/c5ra09562j.

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Crystallization induced emission is observed for bis-pyridyl-ethyl-di-imine and bis-pyridyl-butyl-di-imine. While in case of bis-pyridyl-di-imines, with no alkyl spacer, the quenching is observed in the solid state.

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13

Benz, Scott, e Andrew S. Murkin. "α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions". Beilstein Journal of Organic Chemistry 17 (15 ottobre 2021): 2570–84. http://dx.doi.org/10.3762/bjoc.17.172.

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In the presence of a suitable acid or base, α-hydroxyaldehydes, ketones, and imines can undergo isomerization that features the 1,2-shift of an alkyl or aryl group. In the process, the hydroxy group is converted to a carbonyl and the aldehyde/ketone or imine is converted to an alcohol or amine. Such α-ketol/α-iminol rearrangements are used in a wide variety of synthetic applications including asymmetric synthesis, tandem reactions, and the total synthesis and biosynthesis of natural products. This review explores the use of α-ketol rearrangements in these contexts over the past two decades.

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14

Zhao, Qun, Jin Zhang e Michal Szostak. "Ruthenium(0)-sequential catalysis for the synthesis of sterically hindered amines by C–H arylation/hydrosilylation". Chemical Communications 55, n. 61 (2019): 9003–6. http://dx.doi.org/10.1039/c9cc04072b.

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15

Edwards, Oliver E., Dusan Dvornik, Ralph J. Kolt e Barbara A. Blackwell. "Formation, reactions, and NMR spectra of 1,20-cycloatidanes". Canadian Journal of Chemistry 70, n. 5 (1 maggio 1992): 1397–405. http://dx.doi.org/10.1139/v92-178.

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Imines derived from the alkaloid atisine gave N-acetyl 1,20-cycloatidane derivatives when heated with acetic anhydride. Vigorous alkaline hydrolysis cleaved the cyclopropane ring, regenerating the parent imine. The 1H and 13C NMR spectra of several 1,20-cyclo derivatives have been assigned and compared to those of the parent imines 2. All of the N-acetyl compounds showed doubling of the majority of the NMR resonances, due to amide rotamers. The effects of the cyclopropane ring current are noted.

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16

Laha, Joydev K., K. S. Satyanarayana Tummalapalli e Krupal P. Jethava. "Implications of dynamic imine chemistry for the sustainable synthesis of nitrogen heterocycles via transimination followed by intramolecular cyclisation". Organic & Biomolecular Chemistry 14, n. 8 (2016): 2473–79. http://dx.doi.org/10.1039/c5ob02670a.

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17

Becica, Joseph, Andrew B. Jackson, William G. Dougherty, W. Scott Kassel e Nathan M. West. "Bis-tropolonate complexes of tungsten: scaffolds for selective side-on binding of nitriles, imines and ketones". Dalton Trans. 43, n. 23 (2014): 8738–48. http://dx.doi.org/10.1039/c4dt00734d.

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The bis-tropolonate tungsten(ii) tricarbonyl compound, (trop)₂W(CO)₃ will preferentially bind nitriles, imines, and aldehydes in a side-on fashion. Crystallographic analysis of the imine adduct supports the postulation of 4-electron donation from the imine.

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18

Juneja, Navkiran, Ethan Zahid, Daniel K. Unruh e Kristin M. Hutchins. "Solid-state behaviors of imines: colossal biaxial positive thermal expansion, motion capability, and phase transitions". CrystEngComm 23, n. 25 (2021): 4439–43. http://dx.doi.org/10.1039/d1ce00706h.

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The torsional flexibility of imines affects solid-state packing and properties. Behaviors including colossal thermal expansion, pedal motion, and phase transitions in imine-containing solids are described.

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19

Lorenzini, Fabio, Paolo Marcazzan, Brian O. Patrick e Brian R. James. "Synthesis, characterization, and X-ray structures of three iridium(III)-hydrido-cyclometallated-imine complexes, including the first reported hydrido-(η1-imine)-Ir complex". Canadian Journal of Chemistry 86, n. 3 (1 marzo 2008): 253–60. http://dx.doi.org/10.1139/v07-153.

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Reactions of cis,trans,cis-[Ir(H)2(PPh3)2(solv)2]PF6 (solv = MeOH or Me2CO) with the imines HN=CPh2, (o-HOC6H4)C(Me)=NCH2Ph, and PhC(H)=N(p-F-C6H4) in MeOH or acetone under Ar give the complexes [IrH{NH=C(Ph)(o-C6H4)}(NH=CPh2)(PPh3)2]PF6 (3), [IrH{PhCH2N=C(Me)(o-C6H3OH)}(solv)(PPh3)2]PF6, where solv = MeOH (4) or Me2CO (4a), and [IrH{N(p-F-C6H4)=CH(o-C6H4)}(Me2CO)(PPh3)2]PF6 (5a), which have been isolated and characterized. The imine (C6F5)C(H)=NPh is unreactive toward the Ir precursors. The X-ray structures of 3, 4·2MeOH, and 5a·1/2Me2CO show an η2-N,C-imine moiety coordinated via the N atom and an orthometallated-C atom. Complex 3, which contains both an orthometallated imine and an η1-imine, is the first structurally characterized hydrido-(η1-imine)-Ir complex. Comparisons are made with data for the corresponding Rh systems.Key words: iridium, hydride complexes, imines, fluoroimines, phosphine complexes, orthometallation, crystallography, NMR spectroscopy.

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20

Mao, Kebin, Guoqin Fan, Yuanhong Liu, Shi Li, Xu You e Dan Liu. "Titanium-mediated reductive cross-coupling reactions of imines with terminal alkynes: An efficient route for the synthesis of stereodefined allylic amines". Beilstein Journal of Organic Chemistry 9 (27 marzo 2013): 621–27. http://dx.doi.org/10.3762/bjoc.9.69.

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Low-valency titanium species, generated in situ by using Ti(OiPr)4/2 c-C5H9MgCl reagent, react with imines to give a titanium-imine complex that can couple with terminal alkynes to provide azatitanacyclopentenes with excellent regioselectivity. Stereodefined allylic amines are obtained in good yields after hydrolysis or iodonolysis of the corresponding azatitanacyclopentenes. When ethynylcyclopropane is used as the coupling partner to react with imines in this reaction, the initially generated allylic amine undergoes an unexpected 1,3-amino migration on silica gel during the column chromatography.

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21

A.S.P. Azzouz e D.B.AL-Bakzo. "Determination of Stability for imines derived from carbonyl compounds by conductivity measurements". Tikrit Journal of Pure Science 23, n. 3 (22 maggio 2018): 43–47. http://dx.doi.org/10.25130/tjps.v23i3.499.

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The project explained for the first time, how conductivity method was used in the determination of stability of some imines derived from mother compounds 2-acetyl pyridine, 3 or 4 –hydroxy benzaldehyde, and others. The method as found, simple precise and fast for the determination of stability of imines in 10% ethanol aqueous medium, as measured by evaluation of their conductance. Different conductance values for 10-2 M imine solutions in the range (5.53-180) μmho were collected experimentally as interpreted and discussed.

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22

Banks, Surya R., J. Tanner Morningstar e Mark E. Welker. "Synthesis of Aminopropyltriethoxysilyl-Substituted Imines and Amides". Molbank 2021, n. 3 (18 luglio 2021): M1251. http://dx.doi.org/10.3390/m1251.

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A series of small molecules containing aminopropyltriethoxysilyl-substituted imines and amides were synthesized so that they could potentially be incorporated into self-assembled monolayers (SAMs) on metal oxide surfaces. Simple one-step imine preparations and two-step amide preparations are reported here.

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23

Bosica, Giovanna, Roderick Abdilla, Kaylie Demanuele e Josef Fiteni. "Facile imine synthesis under green conditions using Amberlyst® 15". PeerJ Organic Chemistry 4 (9 agosto 2022): e7. http://dx.doi.org/10.7717/peerj-ochem.7.

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Imines and their derivatives are of great interest to organic synthetic chemists due to their involvement as key intermediates which facilitate the construction of nitrogen heterocycles, particularly the formation of alkaloids. Imine formation by condensation of primary amines with aromatic aldehydes and cyclohexanone has been investigated under environmentally-friendly solventless heterogeneous catalysis. An array of different imines was obtained in excellent yields in appreciably short reaction times using Amberlyst® 15 as a heterogeneous catalyst. The latter was used owing to its high commercial availability, recyclability, ease of separation from the reaction mixture, and versatility.

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24

Wolfsberger, W. "N-(Halogendimethylsilyl)-1 -methylphospholanimine/N-(Halogenodimethylsilyl)-1 -methylphospholane Imines". Zeitschrift für Naturforschung B 55, n. 7 (1 luglio 2000): 557–60. http://dx.doi.org/10.1515/znb-2000-0701.

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N-Trimethylsilyl-1 -methylphospholane imine has been prepared by the Staudinger reaction of 1-methylphospholane with trimethylsilyl azide. Transsilylation reactions of the phosphine imine with dichloro or dibromodimethylsilane lead to dimeric N-(halogenodimethylsilyl)-l-methylphospholane imines with an ionic type of structure, containing a dicationic four-membered Si-N ring system. Upon heating, the chloro compound undergoes a reversible isomerization to give the corresponding covalent monomer.

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25

Zhang, Hongming, Jiahe Zhuang, Xiangrui Feng e Ben Ma. "Co0.6Ni0.4S2/rGO Photocatalyst for One-Pot Synthesis of Imines from Nitroaromatics and Aromatic Alcohols by Transfer Hydrogenation". Coatings 12, n. 12 (23 novembre 2022): 1799. http://dx.doi.org/10.3390/coatings12121799.

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Co0.6Ni0.4S2/rGO catalysts exhibit excellent photocatalytic performance for one-step synthesis of N-benzylideneaniline from nitrobenzene and benzyl alcohol by transfer hydrogenation, and the selectivity and yield of N-benzylideneaniline can reach as high as 93% and 77.2%, respectively. The reaction process for the synthesis of imines can be divided into two steps: benzyl alcohol is oxidized to benzaldehyde, while nitrobenzene is reduced to aniline; benzaldehyde and aniline are condensed to form imines. Under visible light irradiation, photo-induced electrons in Co0.6Ni0.4S2/rGO photocatalyst play an important role in activating nitrobenzene and benzaldehyde. Photo-induced holes are mainly responsible for the partial dehydrogenation of benzyl alcohol to benzaldehyde. Next, aniline molecules condense with benzaldehyde molecules to synthesize imine. The photocatalytic system provides an environmentally friendly for the synthesis of imines and supplies an alternative approach for hydrogen auto-transfer reactions.

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26

Satyam, Killari, Battu Harish, Jagadeesh Babu Nanubolu e Surisetti Suresh. "N-Heterocyclic carbene (NHC)-catalyzed tandem imine umpolung–aza-Michael addition–oxidation of β-carboline cyclic imines". Chemical Communications 56, n. 18 (2020): 2803–6. http://dx.doi.org/10.1039/d0cc00321b.

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N-Heterocyclic carbene (NHC)-catalyzed tandem imine umpolung–aza-Michael addition–oxidation of cyclic imines for the synthesis of a wide range of biologically relevant β-carboline-1-one derivatives has been disclosed.

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27

Wang, Liming, Hao Wu, Ruxin Ding, Zhe Chen e Ying Jin. "Enantioselective Friedel-Crafts Reaction of Indoles with N-Tosylimines Employing Takemoto's Organocatalyst". Current Organic Chemistry 23, n. 15 (28 ottobre 2019): 1688–94. http://dx.doi.org/10.2174/1385272823666190823115333.

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Abstract (sommario):

The asymmetric Friedel-Crafts reaction of indoles with imines provides a direct approach for the enantioselective construction of 3-indolyl methanamine derivatives. In this paper, a series of thiourea/ urea-tertiary amine derivatives have been used to catalyze the asymmetric F-C reaction of indoles with N-tosylimines. The effect of solvent, temperature and catalyst loading amount were investigated. the optimized conditions were determined to be toluene as the solvent with a 5 mol% loading of Takemoto's catalyst 1c at rt. A wide range of substituted indoles and imines were evaluated to explore the scope and general applicability of this reaction. The enantioselectivities were obviously affected by the position of the substituents on the phenyl ring of imines. 4- electron-donating substituted imines appeared to favor higher enantioselectivities. Moreover, indoles containing either electron-donating groups or electron-withdrawing groups were then investigated for the reaction with imines. In all cases, high yields and excellent enantioselectivities could be achieved. Of all the different substrates, the reaction of the 5-OMe substituted indole with 4-chloride substituted imine afforded an optimal yield and enantiomeric excess. Under the screened optimal condition, optically active 3-indolyl-methanamines were obtained in good yields (70-90%) with high enantioselectivities (up to 98%ee). The catalyst type and the substrate scope were broadened in this methodology.

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28

Gamenara, Daniela, e Pablo Domínguez de María. "Enantioselective imine reduction catalyzed by imine reductases and artificial metalloenzymes". Org. Biomol. Chem. 12, n. 19 (2014): 2989–92. http://dx.doi.org/10.1039/c3ob42205d.

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Abstract (sommario):

Adding value to organic synthesis. Novel imine reductases enable the enantioselective reduction of imines to afford chiral amines. Likewise, novel bioinspired artificial metalloenzymes can perform the same reaction as well. Remarkable recent examples are herein discussed.

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29

Kuznetsova, Juliana V., Varvara T. Tkachenko, Lada M. Petrovskaya, Maria E. Filkina, Dmitry E. Shybanov, Yuri K. Grishin, Vitaly A. Roznyatovsky et al. "[3+2]-Cycloaddition of Nitrile Imines to Parabanic Acid Derivatives—An Approach to Novel Spiroimidazolidinediones". International Journal of Molecular Sciences 25, n. 1 (19 dicembre 2023): 18. http://dx.doi.org/10.3390/ijms25010018.

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Abstract (sommario):

Approximately 1,3-Dipolar cycloaddition of imidazolidine derivatives containing exocyclic double bonds is a convenient method of creating spiro-conjugated molecules with promising anticancer activity. In this work, the derivatives of parabanic acid (2-thioxoimidazolidine-4,5-diones and 5-aryliminoimidazolidine-2,4-diones) were first investigated as dipolarophiles in the reactions with nitrile imines. The generation of nitrile imines was carried out either by the addition of tertiary amine to hydrazonoyl chlorides «drop by drop» or using the recently proposed diffusion mixing technique, which led to ~5–15% increases in target compound yields. It was found that the addition of nitrile imines to C=S or C=N exocyclic double bonds led to 1,2,4-thiazolines or triazolines and occurred regioselectively in accordance with the ratio of FMO coefficients of reactants. The yield of the resulting spiro-compound depended on the presence of alkyl substituents in the nitrile imine structure and was significantly decreased in reactions with imines with strong electron donor or electron-withdrawing groups. Some of the obtained compounds showed reasonable in vitro cytotoxicity. IC50 values were calculated for HCT116 (colon cancer) cells using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test.

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30

García-Hernández, Zureima, e François P. Gabbaï. "Synthesis and Properties of 2-(Dimesitylboryl)benzylideneamines". Zeitschrift für Naturforschung B 64, n. 11-12 (1 dicembre 2009): 1381–86. http://dx.doi.org/10.1515/znb-2009-11-1219.

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Abstract (sommario):

Lithiation of 2-(2-bromophenyl)-dioxolane (1) followed by reaction with dimesitylboron fluoride afforded 2-(2-dimesitylborylphenyl)-dioxolane (2) which was deprotected to afford 2- dimesitylboryl-benzaldehyde (3). Compound 3 reacts with aliphatic amines such as n-butylamine and ethanolamine to afford the corresponding imines 2-(dimesitylboryl)benzylidenebutylamine (4) and 2-(dimesitylboryl)benzylideneethanolamine (5), respectively. Structural studies indicate coordination of the imine-nitrogen atom to the boron center. Imines 4 and 5 emit a green fluorescence near 510 nm with quantum yields approaching 10%. TD-DFT calculations suggest that this emission arises from an intramolecular charge-transfer excited state

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31

Al-Shalaan, Abdulla M., Salim S. Al-Showiman e Ibrahim M. Al-Najjar. "Isomerization of imines in platinum-imine complexes". Inorganica Chimica Acta 121, n. 2 (novembre 1986): 127–29. http://dx.doi.org/10.1016/s0020-1693(00)84510-7.

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32

Xu, Wengang, e Naohiko Yoshikai. "Cobalt-catalyzed directed C–H alkenylation of pivalophenone N–H imine with alkenyl phosphates". Beilstein Journal of Organic Chemistry 14 (28 marzo 2018): 709–15. http://dx.doi.org/10.3762/bjoc.14.60.

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Abstract (sommario):

A cobalt–N-heterocyclic carbene (NHC) catalyst efficiently promotes an ortho C–H alkenylation reaction of pivalophenone N–H imine with an alkenyl phosphate. The reaction tolerates various substituted pivalophenone N–H imines as well as cyclic and acyclic alkenyl phosphates.

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33

Fondo, Matilde, Julio Corredoira-Vázquez, Ana M. GarcíaDeibe e Jesús Sanmartín-Matalobos. "An Easy Approach to Obtain Alcohol-Amines by Reduction of Alcohol Functionalized Imines". Proceedings 9, n. 1 (14 marzo 2019): 2. http://dx.doi.org/10.3390/ecsoc-22-05697.

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Abstract (sommario):

The reduction of functionalized imines to yield amines is often an intricate task, since most of the methods described in the literature to reduce imines to amines do not take into account that many reducing agents have also basic character. In this way, iminic compounds that have phenol functions usually produce the phenolic salt of the precursor when they are treated with a basic reducing agent, but not the desired amine. In this work, we describe an easy way of isolating very pure aminic compounds with alcoholic functions in its structure from the corresponding iminic compounds, by using NaBH4 as a reducing agent, and avoiding tedious chromatography or multiple solvent extraction steps.

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34

Lu, Gang, Peng Zhang, Dongqing Sun, Lei Wang, Kebin Zhou, Zhi-Xiang Wang e Guo-Cong Guo. "Gold catalyzed hydrogenations of small imines and nitriles: enhanced reactivity of Au surface toward H2via collaboration with a Lewis base". Chem. Sci. 5, n. 3 (2014): 1082–90. http://dx.doi.org/10.1039/c3sc52851k.

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Abstract (sommario):

Au (111) surface can serve as a Lewis acid to couple with a Lewis base (e.g. imine or nitrile) to form the Au-coupled FLP (frustrated Lewis pair, left) which can cleave H₂, further achieving hydrogenation of small imines and nitriles.

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35

Ghashghaei, Ouldouz, Consiglia Annamaria Manna, Esther Vicente-García, Marc Revés e Rodolfo Lavilla. "Studies on the interaction of isocyanides with imines: reaction scope and mechanistic variations". Beilstein Journal of Organic Chemistry 10 (6 gennaio 2014): 12–17. http://dx.doi.org/10.3762/bjoc.10.3.

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Abstract (sommario):

The interaction of imines with isocyanides has been studied. The main product results from a sequential process involving the attack of two units of isocyanide, under Lewis acid catalysis, upon the carbon–nitrogen double bond of the imine to form the 4-membered ring system. The scope of the reaction regarding the imine and isocyanide ranges has been determined, and also some mechanistic variations and structural features have been described.

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36

Zarei, Maaroof. "One-step Synthesis of β-lactams Using Cyanuric Fluoride". Journal of Chemical Research 37, n. 1 (gennaio 2013): 25–27. http://dx.doi.org/10.3184/174751912x13545429290478.

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Abstract (sommario):

Cyanuric fluoride works as an efficient acid activator reagent for the direct [2+2] ketene–imine cycloaddition of substituted acetic acids and imines in a one-pot synthesis under mild conditions. The yields are good to excellent and the reaction conditions are mild, simple and efficient.

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37

Yamamoto, K., e Masayoshi Higuchi. "Dendritic polyphenylazomethines: Synthesis, structure, and metal-assembling function". Pure and Applied Chemistry 76, n. 7-8 (1 gennaio 2004): 1399–408. http://dx.doi.org/10.1351/pac200476071399.

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Abstract (sommario):

Dendritic polyphenylazomethines (DPAs) were synthesized as novel topological polymer ligands with pi-conjugated structures by the convergent method via dehydration of aromatic ketones with aromatic amines in the presence of TiCl4. DPA G4 molecules are revealed to have a sphere-like structure with a 2.3-nm diameter and are regularly assembled without deformation of the molecule on a plate as observed by means of gel permeation chromatography (GPC), molecular modeling, transmission electron microscopy (TEM), atomic force microscopy (AFM), and pi-A measurements. The stepwise radial complexation in DPAs with SnCl2 was observed as a stepwise shift in the isosbestic point in the UV-vis spectra. The number of added equivalents of SnCl2 required to induce a shift was in agreement with the number of imine groups present in the different shells of the DPAs. These spectral changes suggest that the complexation is proceeding in a stepwise fashion from the core imines to the terminal imines of the DPAs, which was further supported by shell-selective reduction (SSR) of the imines.

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38

Whittaker, Jacob, Suresh Moorthy, Jonathan Cremers, Jason R. Price, John C. McMurtrie e Jack K. Clegg. "Synthesis of Two 2,2′-Bipyridine Containing Macrocycles for the Preparation of Interlocked Architectures". Australian Journal of Chemistry 70, n. 5 (2017): 588. http://dx.doi.org/10.1071/ch16710.

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Abstract (sommario):

The synthesis and characterisation of two 28-membered, 2,2′-bipyridine-containing macrocycles in high yield is reported. The first imine-containing macrocycle was formed via a Williamson ether synthesis and showed no evidence of higher oligomer formation. Reduction of the imines with sodium borohydride produced the second macrocycle quantitatively.

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39

Sadowski, Mikołaj, Jolanta Utnicka, Adrianna Wójtowicz e Karolina Kula. "The global and local Reactivity of C,N-diarylnitryle imines in [3+2] cycloaddition processes with trans-β-nitrostyrene according to Molecular Electron Density Theory: A computational study". Current Chemistry Letters 12, n. 2 (2023): 421–30. http://dx.doi.org/10.5267/j.ccl.2022.11.004.

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Abstract (sommario):

The regioselectivity of the [3+2] cycloaddition reactions between trans-β-nitrostyrene and C,N-diarylnitryle imine analogues as three atom components (TACs) has been studied with the use of Conceptual Density Functional Theory in the framework of Molecular Electron density Theory. Global and local reactivity indices were determined. Presented quantum-chemical computations showed that, for the reaction of nitroalkene with diphenylnitryle imine, the most favourable reaction path is determined by the nucleophilic attack of C3 carbon atom of TAC on an electrophilic Cα carbon atom of nitroalkene. Therefore, the creation of 1,3,4-triphenyl-5-nitro-Δ2-pyrazoline, according to channel B, is more probable. Similarly, to presented conclusion, for reactions of nitroalkene with nitryle imines containing ED group at para position of the phenyl ring also the most favourable reaction paths run through channel B leading to 1,3,4-triphenyl-5-nitro-Δ2-pyrazolines. In turn, reactions of nitroalkene with nitryle imines containing EW group at para position of the phenyl ring have the opposite preference and the most favourable reaction paths is channel A leading to 1,3,5-triphenyl-4-nitro-Δ2-pyrazolines.

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40

Mwansa, Joseph M., Matthew J. Stirling e Michael I. Page. "Changing the kinetic order of enantiomer formation and distinguishing between iminium ion and imine as the reactive species in the asymmetric transfer hydrogenation of substituted imines using a cyclopentadienyl iridium (III) complex". Pure and Applied Chemistry 92, n. 1 (28 gennaio 2020): 107–21. http://dx.doi.org/10.1515/pac-2019-0222.

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Abstract (sommario):

AbstractThe iridium (III) complex of pentamethylcyclopentadiene and (S,S) or (R,R)-1,2-diphenyl-N′-tosylethane-1,2-diamine is an effective catalyst for the asymmetric transfer hydrogenation of imines under acidic conditions. However, the enantiomeric excess (ee) of the product amines from the reduction of 1-methyl-3,4-dihydroisoquinolines in either acetonitrile or dichloromethane, decreases exponentially. The dominant cause of the enantioselectivity is the difference in kinetic order of the formation of the two enantiomers with the S-enantiomer being formed in a first-order process whereas that for the R-enantiomer follows zero-order kinetics when (R,R)-TsDPEN is employed, due to different rate-limiting steps for the two processes. A series of 1-fluorinated methyl-3,4-dihydroisoquinolines were synthesised to change the rate-limiting dissociation of the (R) amine product from Ir (III) so that both enantiomers are formed with the same kinetic order. This results in almost complete removal of the enantioselectivity of the reduction. It has been suggested that reduction of imines using transition metal complexes occurs through the neutral imine rather than the more reactive iminium-ion. α-Substituted imines with electron-withdrawing groups make protonation more difficult but enhance the electrophilicity of the imine carbon facilitating nucleophilic attack. The pKa of the iminium ions of 1-fluorinated methyl-3,4-dihydroisoquinolines were determined. Using the relative rates of the cyclopentadienyl iridium (III) complex catalysed reduction of these 1-fluorinated methyl-3,4-dihydroisoquinoline in acetonitrile and, under the acidic conditions of a 5:2 ratio of formic acid:triethylamine, showed that the iminium ion is the reactive species.

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41

Song, Tao, Yanan Duan, Xiufang Chen e Yong Yang. "Switchable Access to Amines and Imines from Reductive Coupling of Nitroarenes with Alcohols Catalyzed by Biomass-Derived Cobalt Nanoparticles". Catalysts 9, n. 2 (29 gennaio 2019): 116. http://dx.doi.org/10.3390/catal9020116.

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Abstract (sommario):

Cobalt nanoparticles modified with N-doped hierarchical porous carbon derived from biomass are found to be a highly efficient, reusable heterogeneous catalyst for the coupling of nitroarenes with alcohols, selectively affording imines and amines via the borrowing hydrogen strategy for the first time. The product selectivity between imine and amine may be precisely tuned by simple alteration of the reaction conditions without changing the catalyst in one reaction system. In this study, a broad set of complex imines and amines was successfully synthesized in good to high yields with various functional groups tolerated for both nitroarenes and alcohols, highlighting the potentially practical utility of the protocol. This heterogeneous catalyst can be easily removed from the reaction medium by external magnet and can be reused at least four times without significant loss in activity and selectivity.

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42

Kandemir, Hakan, Ibrahim F. Sengul, Naresh Kumar e David StC Black. "Synthesis of Imine and Amine-Linked Macrocycles Containing Tris-Indoles". Australian Journal of Chemistry 70, n. 11 (2017): 1196. http://dx.doi.org/10.1071/ch17264.

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Abstract (sommario):

The synthesis of 21-membered imine- and amine-linked tris-indole macrocycles starting from 7-nitroethylindoles is described. The 7-nitroethylindoles are converted to 2,2′-diindolylmethanes and the nitro groups reduced to amino. The resulting diamines undergo reactions with indole-2,7-dicarbaldehydes to form the macrocyclic imines, which can subsequently be reduced to the macrocyclic amines.

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43

Honraedt, Aurélien, Lucía Méndez, Jean-Marc Campagne e Eric Leclerc. "A Three-Component Reaction for the One-Pot Preparation of β-Amino-α,α-Difluoroketones from Trimethyl(trifluoromethyl)silane (CF3TMS), Acylsilanes and Imines". Synthesis 49, n. 17 (13 giugno 2017): 4082–92. http://dx.doi.org/10.1055/s-0036-1588447.

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Abstract (sommario):

A methodology allowing the direct preparation of β-amino-α,α-difluoroketones from the Ruppert–Prakash reagent (CF3TMS), acyltrimethylsilanes and N-Boc or N-(diphenylphosphinyl)imines is reported. The process, initiated by a catalytic amount of tetra-n-butylammonium difluorotriphenylsilicate (TBAT), involves the addition of CF3TMS to the acylsilane, followed by a Brook rearrangement and elimination of a fluoride anion. The latter promotes the addition of the resulting difluoroenoxysilane to the imine. The higher electrophilicity of the acylsilane compared to the imine allows the direct mixing of all the reagents in a three-component, one-pot process.

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44

Seibel, Zara M., Jeffrey S. Bandar e Tristan H. Lambert. "Enantioenriched α-substituted glutamates/pyroglutamates via enantioselective cyclopropenimine-catalyzed Michael addition of amino ester imines". Beilstein Journal of Organic Chemistry 17 (17 agosto 2021): 2077–84. http://dx.doi.org/10.3762/bjoc.17.134.

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Abstract (sommario):

A procedure for the enantioselective synthesis of α-substituted glutamates and pyroglutamates via a cyclopropenimine-catalyzed Michael addition of amino ester imines is described. Enantioselectivities of up to 94% have been achieved, and a variety of functional groups were found to be compatible. The impact of the catalyst structure and imine substitution is discussed. Compared to other methods, this protocol allows for a broader and more enantioselective access to pyroglutamate derivatives.

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45

Wang, Yunlong, Zongyang Li, Haiying Zhao e Zhenhua Zhang. "Rhodium-Catalyzed Double Isocyanide Insertion via a Vinylcarbodiimide Intermediate for the Synthesis of 2H-Pyrrol-2-imines". Synthesis 51, n. 17 (21 maggio 2019): 3250–58. http://dx.doi.org/10.1055/s-0037-1611830.

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Abstract (sommario):

2H-Pyrrol-2-imine is an important structural motif exhibiting in biologically active compounds and natural products. An efficient rhodium-catalyzed one-pot reaction of one vinyl azide with sequentially with two different isocyanides is reported, which offers an alternative facile access to 3-amino-5-aryl-2H-pyrrol-2-imines bearing various substitution on the nitrogens in good yields. An unstable vinylcarbodiimide is the key intermediate in this cascade reaction.

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46

Ullah, Qasim, NAHID FATEMA, M. VIJJULATHA, Pathan Mohammad Arif, SALMAN AHMED KHAN, MOHAMMED ARIFUDDIN, Syed Kashif Ali e REHAB EBAID AZOOZ. "Green and Efficient Chemo-selective Synthesis of Chalcone Imines (α,β-Unsaturated imine) using Baker’s Yeast". Asian Journal of Chemistry 35, n. 11 (31 ottobre 2023): 2809–14. http://dx.doi.org/10.14233/ajchem.2023.30302.

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Abstract (sommario):

A simple, efficient, chemo-selective and sustainable biocatalytic method for the synthesis of a,b-unsaturated imines or chalcone- mines (3a-l) was developed by using Baker’s yeast. When, chalcones (1a-b) were reacted with the substituted anilines (2a-f) in the presence of Baker’s yeast act as a whole cell biocatalyst at ambient temperature in ethanol as a green solvent to afford the a,b-unsaturated imines or chalcone-imines (3a-l) in good to excellent yield. The reaction procedure was easy to follow and takes place at room temperature (25-28 ºC). The commercially available Baker’s yeast is very cheap and affordable catalyst, easy to use and facilitate this method as an effective and facile chemo-selective synthesis of a,b-unsaturated imines (chalcone-imines) (3a-l). This is the first report about the biocatalytic reactions of a,b-unsaturated imines (chalcone-imines) (3a-l) formation and it is assumed that this method will open an gateway for the organic chemists to design and synthesized chemo-selective chalcone imines.

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47

Lin, Qinghong, Djamal Djaidi, Roger Bishop, Donald C. Craig e Marcia L. Scudder. "Ritter Reactions. XIII Reactivity of Methyl Schiff Bases with Dimethyl Acetylenedicarboxylate and Mercaptoacetic Acid". Australian Journal of Chemistry 51, n. 9 (1998): 799. http://dx.doi.org/10.1071/c98025.

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Abstract (sommario):

Reactions of several methyl imines with dimethyl acetylenedicarboxylate and with mercaptoacetic acid have been studied to investigate further the capricious behaviour of this functionality. The 1 : 1 adduct of imine (1) and dimethyl acetylenedicarboxylate is confirmed as the pyrroloisoquinoline structure (7) by X-ray methods [C17H17NO5, P -1, a 9·037(2), b 9·276(2), c 10·033(2) Å, α 81·99(1), β 81·28(1), γ 64·9(2)°, Z 2, R 0·044]. New products from (2) and dimethyl acetylenedicarboxylate, the 1 : 1 adduct (10) which is readily converted into the known product (9), and the 1 : 2 adduct (12), are described. The structure of the last compound, which arises through a rearrangement process, was determined by X-ray crystallography [C27H36N2O9,P ca21, a 19· 083(4), b 15·217(3), c 9·669(2) Å, Z 4, R 0·038]. Methyl imines (1) and (4) undergo cyclocondensation with mercaptoacetic acid yielding thiazolidinone products but others are inert under similar conditions.

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48

Ravula, Madhu, Siddaramagoud Bandalla, Vijaykumar Dosarapu, Mohan Kurra, Satyanarayana Mavurapu e Chandra Sekhar Vasam. "Selective Synthesis of Imines via Oxidative Coupling of Primary Amines and Oxidation of Secondary Amines by Peroxides and other Competent Oxidants: A Short Review". Oriental Journal Of Chemistry 40, n. 3 (27 giugno 2024): 611–29. http://dx.doi.org/10.13005/ojc/400301.

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Abstract (sommario):

Imines are certainly important constituents of many biomolecules, pharmaceuticals, agrochemicals, and fine chemicals. This review article highlights the standard protocols reported so far for the selective synthesis of imines via catalyzed and non-catalyzed (i) oxidative coupling of primary amines and (ii) oxidation of secondary amines in the presence of some competent/resourceful oxidants other than molecular O2 such as tert-butyl hydroperoxide (TBHP), H2O2, hypervalent iodines, persulfate, hypochlorite, electroactive species and graphene oxide. Indeed, the use of such oxidants offers a cost-effective experimental set-up, operational simplicity and also minimization of by-products. The cooperativity between catalyst, amine substrate, and oxidant is discussed in this review to understand the proposed mechanisms. Three consolidated data tables (Table 1, 2 & 3) are prepared to provide the summary of optimized reaction conditions (type of catalyst, type of oxidant, choice of solvent, amine-to-oxidant ratio, reaction time/temperature, conversion of amine, yield/selectivity of imine) of each article published to have a comparison.

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49

Fukumoto, Yoshiya, Masato Daijo e Naoto Chatani. "Rhenium(I)-catalyzed reaction of terminal alkynes with imines leading to allylamine derivatives". Pure and Applied Chemistry 86, n. 3 (20 marzo 2014): 283–89. http://dx.doi.org/10.1515/pac-2014-5003.

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Abstract (sommario):

Abstract The rhenium-catalyzed reaction of terminal alkynes with imines gives N-alkylideneallylamine derivatives. A diphenylmethyl group as the substituent on the imine nitrogen gave the best result. Deuterium labeling experiments revealed that the regioselective addition of both the hydrogen and the N-alkylideneaminoalkyl group to the terminal alkynes also proceeded stereoselectively. While alkynes bearing primary and secondary alkyl-, vinyl-, and aryl groups were applicable to the catalytic reaction, tertiary alkyl- and silyl-substituted alkynes gave propargylamines. The C–C bond-forming step via the nucleophilic attack of the alkynyl β-carbon on the imine carbon leading to the formation of a vinylidene rhenium species appears to be involved in the catalytic cycle.

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50

Constantin, Catalin Paul, Andra Elena Bejan e Mariana Dana Damaceanu. "The Chromic Response to Environment of some Imine-Based Oligomers". Key Engineering Materials 826 (ottobre 2019): 91–101. http://dx.doi.org/10.4028/www.scientific.net/kem.826.91.

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Abstract (sommario):

Among the organic materials widely studied for applications in advanced techniques, imine-based compounds (or azomethines) have received considerable attention due to their ability to reversibly change the color under the action of an external stimulus. The halochromic or photochromic behavior of imines is based on the protonation or photoizomerization ability of the imine linkage, the color changing effect occurring in response to the change in pH of the surrounding medium or electromagnetic radiation absorption. Starting from these aspects, three imine-based oligomers with a donor-acceptor-donor topology containing phenoxazine as the donor unit and diphenyl-1,3,4-oxadiazole, 9,9-diphenylfluorene or fluorene as an acceptor moiety were thoroughly investigated with respect to their protonation and photoiradiation behavior, evaluated by means of photo-physics analysis.

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