- A asymmetric to P for the preparation of compounds (by machine translation)
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The present invention discloses a non-symmetrical P-composition preparation method, in order to backward and halogenated aromatic hydrocarbons as raw material, solid alkali catalyst in dichloromethane in a two-phase system to conduct the condensation reaction, to obtain the asymmetric double-substituted jingjing passes through catalytic oxidation, to prepare the asymmetric P-compound. For the method of the invention the product yield is greater than 85% and above, the purity of the product reach 98% and above. The invention compared with the prior art, safe and convenient operation, the operating environment is greatly improved, avoiding the danger in operation of the diazotization step. The invention mild reaction conditions, good selectivity, process is easy to control, the un-reacted organic raw materials can be recycled, thereby greatly reducing the environmental protection COD treatment intensity, the product quality is stable, it is suitable for industrial production. (by machine translation)
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- When Do Strongly Coupled Diradicals Show Strongly Coupled Reactivity? Thermodynamics and Kinetics of Hydrogen Atom Transfer Reactions of Palladium and Platinum Bis(iminosemiquinone) Complexes
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The 2,2′-biphenylene-bridged bis(iminosemiquinone) complexes (tBuClip)M [tBuClipH4 = 4,4′-di-tert-butyl-N,N′-bis(3,5-di-tert-butyl-2-hydroxyphenyl)-2,2′-diaminobiphenyl; M = Pd, Pt] can be reduced to the bis(aminophenoxide) complexes (tBuClipH2)M by reaction with hydrazobenzene (M = Pd) or by catalytic hydrogenation (M = Pt). The palladium complex with one aminophenoxide ligand and one iminosemiquinone ligand, (tBuClipH)Pd, is generated by comproportionation of (tBuClip)Pd with (tBuClipH2)Pd in a process that is both slow (0.06 M-1 s-1 in toluene at 23 °C) and only modestly favorable (Kcom = 1.9 in CDCl3), indicating that both N-H bonds have essentially the same bond strength. The mono(iminoquinone) complex (tBuClipH)Pt has not been observed, indicating that the platinum analogue shows no tendency to comproportionate (Kcom tBuClipH2)Pt to (tBuClip)Pd occurring with ?G° = ?8.9 kcal mol-1. The palladium complex (tBuClipH2)Pd reacts with nitroxyl radicals in two observable steps, with the first hydrogen transfer taking place slightly faster than the second. In the platinum analogue, the first hydrogen transfer is much slower than the second, presumably because the N-H bond in the monoradical complex (tBuClipH)Pt is unusually weak. Using driving force-rate correlations, it is estimated that this bond has a BDFE of 55.1 kcal mol-1, which is 7.1 kcal mol-1 weaker than that of the first N-H bond in (tBuClipH2)Pt. The two radical centers in the platinum, but not the palladium, complex thus act in concert with each other and display a strong thermodynamic bias toward two-electron reactivity. The greater thermodynamic and kinetic coupling in the platinum complex is attributed to the stronger metal-ligand ? interactions in this compound.
- Conner, Kyle M.,Arostegui, AnnaMaria C.,Swanson, Daniel D.,Brown, Seth N.
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p. 9696 - 9707
(2018/08/28)
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- Aromatic amine oxidation process for preparing aromatic azobenzene method
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The invention relates to a method for preparing an aromatic azo compound by utilizing aromatic amine oxidation. In the method, air or oxygen serves as an oxygen source, and under the effect of a catalyst, aromatic amine is oxidized into the aromatic azo compound. The method is high in oxidization efficiency and product yield; the air or the oxygen serves as the oxygen source, and the method is economical and environmentally friendly. The product and the catalyst can be separated easily, and the aftertreatment is simple. The catalyst is easy to reuse, and the method has very good application prospect.
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Paragraph 0024; 0026-0027
(2017/10/11)
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- NH4I/tert-butyl hydroperoxide-promoted oxidative C–N cleavage of tertiary amines leading to nitroaromatic compounds
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A NH4I/tert-butyl hydroperoxide-promoted oxidation of tertiary N-aryl-N,N-dialkylamines in DMSO has been developed to access nitroaromatic compounds. This methodology involves sequential N-dealkylation reactions in one-pot and a radical pathway is proposed.
- Shao, Ying,Zheng, Hao,Wu, Zhuhong,Huang, Lei,Tong, Jingjing,Wu, Ming,Sun, Xiaoqiang
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p. 504 - 508
(2017/10/03)
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- Formal [4+2] cycloaddition of 3-ethoxycyclobutanones with azo compounds
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Azobenzenes reacted with 3-ethoxycyclobutanoes to give 2,3-dihydro-pyridazin-4(1H)-ones by using EtAlCl2as a Lewis acid. Thus, ring cleavage of 3-ethoxycyclobutanones took place to form a zwitterionic intermediate by activation with EtAlCl2, and intermolecular formal [4+2] cycloaddition of the zwitterionic intermediate proceeded with azobenzenes to give 2,3-dihydro-pyridazin-4(1H)-ones after elimination of ethanol. Regioselectivity for cycloaddition of unsymmetrical azobenzenes, ring contraction and chemoselective reduction of 2,3-dihydro-pyridazin-4(1H)-ones, and [4+2] cycloaddition to 4-phenyl-1,2,4-triazolin-3,5-dione are also described.
- Shima, Yusuke,Matsuo, Jun-ichi
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supporting information
p. 4066 - 4069
(2016/08/18)
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- Zirconium-catalysed Oxidation of Primary Aromatic Amines to Nitro Compounds Using tert-Butylhydroperoxide
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A broad range of primary aromatic amines (1a-x) with electron donating and accepting substituents are oxidized in good to excellent yields to the nitro compounds 3a-x using tert-butylhydroperoxide as the oxidant and Zr(OtBu)4 as the catalyst. The corresponding nitroso compounds 2m,-2n, 2s and 2u can be isolated in the conversion of electron-rich anilines 1m, 1n, 1s and 1u. The aminopyridines 5a-d are also converted to the corresponding nitropyridines 6a-d, but in lower yields (41-47%).
- Krohn, Karsten,Kuepke, Jochen,Rieger, Hagen
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p. 335 - 339
(2007/10/03)
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- Insertions of Electrophiles into Metal-Carbon Bonds: Formation of New Carbon-Nitrogen Linkages Mediated by the (ν5-Cyclopentadienyl)dinitrosylchromium Group
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Electrophiles NE+ (E=O, p-O2NC6H4N, or S) undergo unprecedented insertions into the Cr-C ? bonds of CpCr(NO)2R complexes (Cp-η5-C5H5; R=Me, CH2SiMe3, or Ph) to afford + cationic complexes.Present evidence is consistent with these insertions occurring via charge-controlled, intramolecular attacks by NE+ at the Cr-R groups in classical SE2 processes.When R=Me and E=O, the initially formed product isomerizes intramoleculary to the novel formaldoxime complex, +, which is isolable as its PF6- salt.Single crystals of this salt and that resulting from the reaction of +BF4- with CpCr(NO)2Me have been subjected to X-ray crystallographic analyses. +PF6- crystallizes in the monoclinic space group P21/c with cell dimensions a=7.903 (3) Angstroem, b=12.192 (2) Angstroem, c=13.417 (5) Angstroem, β=95.59 (3) deg.Similarly, crystals of +BF4- are also monoclinic , space group P21/c, but with cell dimensions a=8.300 (1) Angstroem, b=16.964 (2) Angstroem, c=12.536 (2) Angstroem, and β=101.87 (1) deg.The structures of the complexes were refined to final RF values of 0.045 and 0.054, respectively.The most chemically interesting feature of both molecular structures is that the newly formed formaldoxime and p-nitrophenylmethyldiazene ligands function as Lewis bases through nitrogen atoms toward the formally 16-electron + cations.These ligands may be displaced from the chromium's coordination sphere by the more strongly coordinating Cl- anion.The resulting CpCr(NO)2Cl can be reconverterd to CpCr(NO)2R by treatment with the appropriate Grignard or organoaluminum reagent, thereby completing a cycle by regenerating the initial organometallic reactant.The entire sequence of stoichiometric reactions forming the cycle thus constitutes a selective method for the formation of new carbon-nitrogen bonds, the net organic conversions mediated by the CpCr(NO)2 group being NE+ + R- -> N(E)R.
- Legzdins, Peter.,Richter-Addo, Georg B.,Wassink, Berend,Einstein, Frederick W. B.,Jones, Richard H.,Willis, Anthony C.
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p. 2097 - 2104
(2007/10/02)
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- Studies on the Reactivity of Azoxybenzenes. Part 12. αβ-Interconversion of para-Monosubstituted Azoxybenzenes in the Wallach Rearrangement
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Under the reaction conditions for the Wallach rearrangement, 4-methyl-ONN-(1α), 4-methyl-NNO-(1β), 4-nitro-ONN-(2α), and 4-nitro-NNO-azoxybenzene (2β) were found to undergo αβ-interconversion, while 4-bromo-ONN-(3α) and 4-bromo-NNO-azoxybenzene (3β) do not.The αβ-interconversion occurs with both mono- and di-protonated forms of the azoxybenzenes.
- Yamamoto, Jiro,Aimi, Hironori,Masuda, Yasuko,Sumida, Takashi,Umezo, Masahiro,Matuura, Teruo
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p. 1565 - 1568
(2007/10/02)
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