- Arylhydrazine trapping of benzynes: Mechanistic insights and a route to azoarenes
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Arylhydrazines (ArNαHNβH2) are ambident nucleophiles. We describe here their reactivity with benzynes generated in situ by thermal cyclization of several multiynes. Products arising from attack of both the alpha- and beta-nitrogen atoms are observed. These competitive modes of reaction were explored by DFT calculations. Substituent effects on the site-selectivity for several substituted phenylhydrazines were explored. Interestingly, the hydrazo products from beta-attack (ArNHNHAr') can be oxidized, sometimes in situ by oxygen alone, to give structurally complex, unsymmetrical azoarenes (ArN=NAr'). Toluenesulfonohydrazide and benzohydrazide analogues were each demonstrated to undergo similar transformations, including oxidation to the corresponding benzyne-trapped azo compounds.
- Sneddon, Dorian S.,Hoye, Thomas R.
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- Palladium-catalyzed monoarylation of arylhydrazines with aryl tosylates
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A palladium-catalyzed C-N bond coupling reaction between arylhydrazines and aryl tosylates for facile synthesis of unsymmetrical N,N-diarylhydrazines has been developed. Employing the catalyst system of Pd(TFA)2 associated with newly developed phosphine ligand L1, the monoarylation of arylhydrazine proceeds smoothly to afford desired products in good-to-excellent yields (up to 95%) with good functional group compatibility. This method provides an alternative synthetic pathway for accessing structurally diversified N,N-diarylhydrazines from simple and easily accessible coupling components.
- Huang, Yange,Choy, Pui Ying,Wang, Junya,Tse, Man-Kin,Raymond Wai-Yin Sun,Albert Sun-Chi Chan,Kwong, Fuk Yee
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p. 14664 - 14673
(2020/12/29)
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- Rh(iii)-catalyzed, hydrazine-directed C-H functionalization with 1-alkynylcyclobutanols: A new strategy for 1: H -indazoles
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Rh(iii)-catalyzed coupling of phenylhydrazines with 1-alkynylcyclobutanols was realized through a hydrazine-directed C-H functionalization pathway. This [4+1] annulation, based on the cleavage of a Csp-Csp triple bond in alkynylcyclobutanol, provides a new pathway to prepare diverse 1H-indazoles under mild reaction conditions. This journal is
- Zhang, Lei,Chen, Junyu,Chen, Xiahe,Zheng, Xiangyun,Zhou, Jian,Zhong, Tianshuo,Chen, Zhiwei,Yang, Yun-Fang,Jiang, Xinpeng,She, Yuan-Bin,Yu, Chuanming
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p. 7415 - 7418
(2020/07/15)
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- 4-amino diphenylamine preparation method
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The invention discloses a 4-amino diphenylamine preparation method which includes the steps: slowly dropping concentrated hydrochloric acid into concentrated sulfuric acid, drying generated HCl gas bythe concentrated sulfuric acid and then leading the HCl gas into n-butyl alcohol for absorbing the gas; adding diphenylamine, sodium nitrite, water and methylbenzene, dissolving the diphenylamine bystirring, and then dropping hydrogen chloride for reaction with n-butyl alcohol solution; performing standing and liquid separation, removing water phase and organic phase vacuum desolvation agents, adding water, stirring the solution and performing suction filtration, washing and drying to obtain 4-nitroso diphenylamine; adding the 4-nitroso diphenylamine into an autoclave, adding solvents and catalysts, replacing air in the autoclave by hydrogen and performing hydrogenation reaction; filtering catalyzed hydrogenation liquid, decompressing the desolvation agents and finally performing rectification to obtain 4-amino diphenylamine. According to the preparation method, under the condition of low and medium pressure, composite skeleton nickel catalysts replace traditional noble metal catalysts for hydrogenation reduction of 4-amino diphenylamine, waste gas, waste water and industrial residues are fewer, environmental protection is benefited, and production cost is reduced.
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Paragraph 0024-0065
(2019/04/06)
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- Preparation method of 9-anthraldehyde-1, 1-diphenylhydrazone
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The invention relates to a preparation method of 9-anthraldehyde-1, 1-diphenylhydrazone. The preparation method comprises that anthracene, phosphorous oxychloride and N, N-dimethyl formamide are added into a reaction container, the materials undergo a reaction at a temperature of 60-120 DEG C for 6-48h to produce 9-anthraldehyde, N-nitrosodiphenylamine, zinc, acetate acid gracial and an alcohol solvent are added into the reaction container, the mixture undergoes a reaction at a temperature of 0-40 DEG C for 1-9h to produce 1, 1-diphenylhydrazine, 9-anthraldehyde and 1, 1-diphenylhydrazine are added into the reaction container, the mixture undergoes a reaction, the reaction product is cooled and precipitated, and the crystals are filtered and then are recrystallized in benzene so that 9-anthraldehyde-1, 1-diphenylhydrazone is obtained. Through simple recrystallization of the desired compound, a product with purity greater than 99.5% is obtained. The preparation method has the advantages of low raw material cost, mild reaction conditions and high desired product yield. The preparation method provides possibility for use of the hydrazone compound as a semi-conducting material in research on organic electroluminescent devices and organic light conductors.
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Paragraph 0030; 0034; 0035; 0038; 0041; 0045; 0049; 0053
(2017/02/24)
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- Diaza [1,4] Wittig-type rearrangement of N-allylic-N-Boc-hydrazines into γ-amino- N -Boc-enamines
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Diaza [1,4] Wittig-type rearrangement of N-allylic-N-Boc-hydrazines into γ-amino-N-Boc-enamines was demonstrated. The scope and limitation, experimental mechanistic studies, and a proposed reaction mechanism were also described.
- Tayama, Eiji,Kobayashi, Yoshiaki,Toma, Yuka
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supporting information
p. 10570 - 10573
(2016/09/02)
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- Copper(ii)-catalyzed coupling reaction: An efficient and regioselective approach to N′,N′-diaryl acylhydrazines
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Using N′-aryl acylhydrazines as aryl donors, a novel copper(ii)-catalyzed homo-coupling reaction of N′-aryl acylhydrazines has been developed for the synthesis of N′,N′-diaryl acylhydrazines. We also provided a complementary procedure for the preparation of unsymmetrical diaryl acylhydrazines via cross-coupling reaction. These protocols featured mild reaction conditions, wide functional group tolerance and highly regioselective products. Control experiments indicated that this kind of coupling reaction might undergo a transient acyl diazene intermediate. This journal is
- Zhang, Ji-Quan,Huang, Gong-Bin,Weng, Jiang,Lu, Gui,Chan, Albert S. C.
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p. 2055 - 2063
(2015/03/05)
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- An easy route to N,N-diarylhydrazines by Cu-catalyzed arylation of pyridine-2-carbaldehyde hydrazones with aryl halides
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A copper-catalyzed C-N coupling reaction is described for the preparation of pyridine-2-carbaldehyde N,N-diarylhydrazones by the arylation of N-mono- or -non-substituted hydrazones with aryl bromides/iodides, and the subsequent conversion of the hydrazones into N,N-diarylhydrazines by a transimination process with an aqueous solution of H2NNH2. The reaction features the use of CuI as the catalyst without the need for external ligands. This methodology provides a convenient alternative to the synthesis of structurally diverse N,N-diarylhydrazines from simple, easily accessible precursors. Copyright
- Wu, Wei,Li, Xin-Le,Fan, Xin-Heng,Yang, Lian-Ming
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supporting information
p. 862 - 867
(2013/03/28)
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- PROCESS FOR PRODUCING HYDRAZONE COMPOUND
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The present invention provides a process for producing a hydrazone compound represented by the general formula (5): which comprises a step of condensing a hydrazine compound represented by the general formula (3): with a carbonyl compound represented by the general formula (4): without taking the hydrazine compound out of a reactor. According to the invention, the target hydrazone compound can be obtained in high quality and in a high yield without taking the hydrazine compound out of the reactor at all, the hydrazine compound being a reaction intermediate which is structurally unstable and has a fear of influencing safety of workers owing to its toxicity (mutagenicity).
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Page/Page column 7; 8
(2008/06/13)
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- Synthesis and properties of amorphous hole transport materials of triphenylamine based trihydrazones
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A novel class of amorphous state triphenylamine-based trihydrazones were synthesized by condensation reaction of tris(p-formylphenyl)amine with N-methyl-N-phenyl hydrazine, N,N-diphenylhydrazine, N-1-naphthyl-N-phenyl- hydrazine, and N-2-naphthyl-N-phenyl-hydrazine, respectively, and characterized using different scanning calorimetry (DSC) and cyclic voltammetry (CV).
- Jiang, Ke Jian,Sun, Ya Li,Shao, Ke Feng,Yang, Lian Ming
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- N-phenylation of N-arylaminophthalimides with triphenylbismuth and cupric acetate: A convenient synthesis of 1-aryl-1-phenylhydrazines
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Synthesis of 1-aryl-1-phenylhydrazines (2) from N-aryl-N- phenylaminophthalimides (1) which were synthesized by the phenylation of 1 with triphenylbismuth and cupric acetate is described.
- Aoki, Yutaka,Saito, Yuko,Sakamoto, Takeshi,Kikugawa, Yasuo
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p. 131 - 140
(2007/10/03)
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- Investigation of the Potential of Molybdenum(VI) Hydrazido(2-) Complexes as Sources of Nitrenium Ions: Cleavage of the N-N Bond and Incorporation of the β-Nitrogen Group into Solvent Molecules
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Photolyis or thermolysis of bis(N,N-dimethyldithiocarbamato)bismolybdenum(VI) complexes in 1,1,2,2-tetrachloroethane results predominantly in transfer of the hydrazido group to the solvent with formation of dichloroacetohydrazides.A small amount of the corresponding dichloroacetamides are produced by N-N cleavage and N(R)Ph transfer.In contrast, the latter process dominates the reaction of dichlorobis(N,N-dimethyldithiocarbamato)mono-molybdenum(VI) complexes with silver nitrate in alcohols occuring concomitantly with ring methoxylation and nitration and N-nitrosation.Neither transfer of N(R)Ph appears to involve free nitrenium ions.
- Baum, Marc M.,Smith, Edward H.
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p. 2513 - 2520
(2007/10/02)
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- MANY-ELECTRON ELECTRODE PROCESSES. XIII. PRODUCTS OF THE ELECTROLYSIS OF N-NITRO AND N-NITROSO AMINES
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A study was made of the factors influencing the relative yields of the corresponding amines and hydrazines in the reduction of 4-nitro- and 4-nitroso-morpholines and N-nitrosodiphenylamine in DMF and acetonitrile in presence of acetic and benzoic acids.The relative yield of the hydrazine in the reduction of N-nitroso amines rises with rise in the concentration of the carboxylic acid, rise in the basicity of the amine nitrogen atom in the depolarizer molecule, and fall in the basicity of the organic solvent.
- Krgin, Yu. M.,Latypova, V. Z.,Supyrev, A. V.,Zhuikov, V. V.
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p. 1510 - 1513
(2007/10/02)
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- An efficient synthesis of 1,1-disubstituted hydrazines
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1,1-disubstituted hydrazines were prepared from the corresponding 1,1-disubstituted ureas by means of the Hofmann rearrangement reaction. The yields were fairly good, except from the ureas susceptible to oxidation, and thus the present method represents an additional and efficient procedure for the synthesis of 1,1-disubstituted hydrazines.
- Murakami,Yokoyama,Sasakura,Tamagawa
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p. 423 - 428
(2007/10/02)
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- METAL-ASSISTED REACTIONS-PART 11 RAPID REDUCTION OF N-NITROSOAMINES TO N,N-DISUBSTITUTED HYDRAZINES; THE UTILITY OF SOME LOW-VALENT TITANIUM REAGENTS
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The rapid reduction of N-nitrosoamines to N,N-disubstituted hydrazines by a low-valent titanium reagent is described.The reagent is selective in that many other functional groups are unaffected by it.The nature of the low-valent titanium reagent is discussed in terms of experimental results of comparisons of its reactivity and that of other low-valent titanium reducing agents.
- Entwistle, Ian D.,Johnstone, A. W.,Wilby, Anna H.
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p. 419 - 423
(2007/10/02)
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- Reduction of N-nitrosodiphenylamine to the corresponding hydrazine by guinea pig liver preparations
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The present study provides first evidence for enzymatic reduction of a noncyclic nitrosamine to the corresponding hydrazine. Under anaerobic conditions, N-nitrosodiphenylamine was reduced to 1,1-diphenylhydrazine by guinea pig liver 9,000 xg supernatant or cytosol in the presence of an NADPH-generating system and FAD, or NADH and FAD. However, guinea pig liver microsomes did not catalyze the reduction of the nitrosamine at all. The reduction product was isolated from the reaction mixture and identified unequivocally by comparing with authentic samples its mass and UV spectra, and its behavior in HPLC and TLC. Under aerobic conditions, no formation of the hydrazine was observed by HPLC and TLC examinations. However, when aerobic incubation was performed in the presence of acetaldehyde, a reduction product was isolated and identified as the acetaldehyde hydrazone derivative.
- Tatsumi,Yamada
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p. 3842 - 3845
(2007/10/02)
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