- Visible-Light-Mediated Umpolung Reactivity of Imines: Ketimine Reductions with Cy2NMe and Water
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A novel carbanionic reactivity of imines mediated by photoredox catalysis is demonstrated. The umpolung imine reactivity is exemplified by proton abstraction from water as a key step in the reduction of benzophenone ketimines to amines (up to 98% yield). Deuterium is introduced into amines efficiently using D2O as an inexpensive deuterium source (≥95% D ratio). The mechanism of this unusual transformation is probed.
- Wang, Rui,Ma, Mengyue,Gong, Xu,Panetti, Grace B.,Fan, Xinyuan,Walsh, Patrick J.
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supporting information
p. 2433 - 2436
(2018/04/27)
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- Simplified ketimine preparation
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An extremely simple method for preparing imines from aryl and alkylaryl ketones and a variety of amines is presented. The process involves the diffusion of the appropriate amine vapor from one arm of an H-tube into the other arm containing the ketone. Most reactions are quantitative, and, in many cases, there is no real work-up or purification required.
- Thienthong, Neeranat,Bergman, Ylva E.,Perlmutter, Patrick
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experimental part
p. 2683 - 2693
(2009/12/06)
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- Photolysis of 3-Methyl-5,5-diphenyl-3,5-dihydro-4H-1,2,3-triazol-4-one
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Irradiation (λ >/= 280 nm) of a degassed solution in deuterated benzene of the dihydro-1,2,3-triazolone 5 yields the dihydroindolone 7, the imine 9, and its photoreduction product 10, besides molecular nitrogen. Key Words: 4H-1,2,3-Triazol-4-one, 3,5-dihydro- / Photoextrusion of molecular nitrogen / Indol-2-one, 2,3-dihydro- / Aziridone / α-Lactam / Decarbonylation
- Quast, Helmut,Hergenroether, Thomas
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p. 2625 - 2628
(2007/10/02)
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- Electron Paramagnetic Resonance Study of Imine Radical Cations in Low-temperature Solid Matrices
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A series of imine radical cations has been studied by EPR spectroscopy, generated in low-temperature halogenocarbon matrices by γ-radiolysis.Radicals of the type ArCH=NR.+ tend to be formed in the 2A'state, corresponding to ionisation of the in-plane (mainly the nitrogen lone-pair) a' orbital (I).These are isostructural with the corresponding vinyl radicals and show angular geometries at the radical centres and large couplings (ca. 85 G) to the proton trans to the nominally nitrogen-localised SOMO (I).When R = But, a 12 G long-range coupling is observed to a single proton from the But group, arising via the W-configuration (II).This coupling was found to persist in the CFCl3 matrix up to its melting point (ca. 160 K), but was lost reversibly in the higher melting CCl4 matrix at ca. 200 K. When R = phenyl, the radical centre is rendered linear, because of the partial ?-bonding between the aromatic ring and the nitrogen atom due to delocalisation of the unpaired electron, as shown by a fall in the parallel (14N) coupling with a concomitant increase in the nitrogen 2p/2s ratio, and by the observation of couplings to the ortho and para phenyl protons. For imines derived from benzophenone (Ph2C=NR) the tendency is for ionisation to occur from the ?-orbital (III) which has large spin densities on the para carbon atoms. Benzophenone imine (Ph2C=NH), in addition to forming the ?-state (III), was found to deprotonate, giving rise to the Ph2C=N. radical.Similar behaviour was shown by benzophenone oxime, which gave only the corresponding iminoxyl radical (Ph2C=N-O.), and we propose that this is due to the dissolution of the latter two materials in the form of hydrogen-bonded molecular clusters in the non-polar freon solvent, thus facilitating deprotonation of the primary cations.
- Rhodes, Christopher J.,Agirbas, Hikmet
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p. 3303 - 3308
(2007/10/02)
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- Reactions of N-Halo-N-methylbenzylamines with MeONa-MeOH and t-BuOK-t-BuOH. Effects of β-Carbon Substituent and Base-Solvent System upon the Imine-Forming Transition State
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Elimination reactions of YC6H4CH(R)N(X)CH3 in which R = Me and Ph and X = Cl and Br promoted by MeONa-MeOH and t-BuOK-t-BuOH have been studied kinetically.The elimination reactions are regiospecific, producing only the corresponding N-benzylidenemethylami
- Bartsch, Richard A.,Cho, Bong Rae
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p. 2252 - 2257
(2007/10/02)
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- Thermolyse et photolyse de tetrazolines
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The thermolysis of tetrazolines leads to diaziridines the cyclic carbon atom bears two hydrogens or one hydrogen and a methyl group.If one of the substituents of this carbon is aromatic, two cycloreversions may be observed, giving azides and imines.The photolysis at low temperature leads to diaziridines, except when the cyclic carbon atom bears two insaturated substituents.
- Carboni, B.,Tonnard, F.,Carrie, R.
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p. 525 - 530
(2007/10/02)
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- SYNTHESIS OF ARYLIMINES FROM N-SILYLAMIDES AND ARYLLITHIUM COMPOUNDS
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Various arylimines were synthesized by the addition of N-silylated-N-alkyl- or N-aryl-amides to aryllithium compounds.
- Feringa, Ben L.,Jansen, F. G. A.
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p. 507 - 508
(2007/10/02)
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- A CONVENIENT SYNTHETIC METHOD FOR SCHIFF BASES. THE TRIMETHYLSILYL TRIFLUOROMETHANESULFONATE-CATALYZED REACTION OF N,N-BIS(TRIMETHYLSILYL)AMINES WITH ALDEHYDES AND KETONES
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N,N-Bis(trimethylsilyl)amines react with aldehydes or ketones in the presence of trimethylsilyl trifluoromethanesulfonate to give Schiff bases in high yields.In situ utilization of the reaction solution as the Schiff base is also demonstrated.
- Morimoto, Toshiaki,Sekiya, Minoru
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p. 1371 - 1372
(2007/10/02)
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- Photolysis of Alkyl Azides. Evidence for a Nonnitrene Mechanism
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The photolyses of nine sec- and tert-alkyl azides have been studied in detail.The products consist of imines derived from 1,2-shifts of groups on the alkyl carbon atom α to the azide nitrogen atom.No evidence of typical nitrene processes (aromatic substitution, aliphatic C-H insertion) was found.The imine product distributions are rationalized on the basis of a preferred migration orientation in the photochemically excited azide, along with a consideration of either ground or excited state rotational equilibration of the azide.Photolyses of selected azides carried out over an approximately 200 deg C temperature range allow an estimation of apparent activation energy differences between different group migrations.These energy differences are in the range of 70-493 cal/mol and are related to rotational equilibration of the alkyl azide.
- Kyba, Evan P.,Abramovitch, Rudolph A.
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p. 735 - 740
(2007/10/02)
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