- Method for preparing 1 - chloronaphthalene
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The invention specifically relates to a novel preparation method for 1-chloronaphthalene, belonging to the technical field of fine chemical engineering. The preparation method comprises a step of reacting naphthalene with chlorine at 50 to 80 DEG C and at a normal pressure so as to obtain a reaction solution in the presence of a solvent and a catalyst, wherein the solvent is kerosene; the catalystis one or more selected from a group consisting of ferric sulfide, ferrous sulfide and copper sulfide; reaction temperature is 50 to 80 DEG C; and reaction time is 2 to 3 h. According to the preparation method for 1-chloronaphthalene, the conversion rate of naphthalene is 100%, the content of 1-chloronaphthalene in the reaction solution is 90% or more, and the reaction is carried out at normal temperature and normal pressure; so energy consumption is lowered, and the conversion rate is increased.
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Paragraph 0013-0022
(2021/03/23)
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- A Visible Light and Iron-mediated Carbocationic Route to Polysubstituted 1-Halonaphthalenes by Benzannulation using Allylbenzenes and Polyhalomethanes
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A wide array of polysubstituted 1-bromo and chloronaphthalenes are obtained from coupling of allylbenzenes and polyhalomethanes. The reaction is mediated by iron metal under visible light irradiation and proceeds via a Kharasch addition intermediate followed by intramolecular FeIII mediated Friedel-Crafts alkylation, with the formation of two Csp2?Csp2 bonds in the process. This method gives easy access to 1-halonaphthalenes with substituent(s) at C-5 to C-8 that are otherwise hard to synthesize. (Figure presented.).
- Roslan, Irwan Iskandar,Zhang, Hongwei,Ng, Kian-Hong,Jaenicke, Stephan,Chuah, Gaik-Khuan
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p. 1007 - 1013
(2020/12/30)
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- Triptycenyl Sulfide: A Practical and Active Catalyst for Electrophilic Aromatic Halogenation Using N-Halosuccinimides
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A Lewis base catalyst Trip-SMe (Trip = triptycenyl) for electrophilic aromatic halogenation using N-halosuccinimides (NXS) is introduced. In the presence of an appropriate activator (as a noncoordinating-anion source), a series of unactivated aromatic compounds were halogenated at ambient temperature using NXS. This catalytic system was applicable to transformations that are currently unachievable except for the use of Br2 or Cl2: e.g., multihalogenation of naphthalene, regioselective bromination of BINOL, etc. Controlled experiments revealed that the triptycenyl substituent exerts a crucial role for the catalytic activity, and kinetic experiments implied the occurrence of a sulfonium salt [Trip-S(Me)Br][SbF6] as an active species. Compared to simple dialkyl sulfides, Trip-SMe exhibited a significant charge-separated ion pair character within the halonium complex whose structural information was obtained by the single-crystal X-ray analysis. A preliminary computational study disclosed that the πsystem of the triptycenyl functionality is a key motif to consolidate the enhancement of electrophilicity.
- Nishii, Yuji,Ikeda, Mitsuhiro,Hayashi, Yoshihiro,Kawauchi, Susumu,Miura, Masahiro
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supporting information
p. 1621 - 1629
(2020/02/04)
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- Amplification of Trichloroisocyanuric Acid (TCCA) Reactivity for Chlorination of Arenes and Heteroarenes via Catalytic Organic Dye Activation
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Heteroarenes and arenes that contain electron-withdrawing groups are chlorinated in good to excellent yields (scalable to gram scale) using trichloroisocyanuric acid (TCCA) and catalytic Brilliant Green (BG). Visible-light activation of BG serves to amplify the electrophilic nature of TCCA, providing a mild alternative approach to acid-promoted chlorination of deactivated (hetero)aromatic substrates. The utility of the TCCA/BG system is demonstrated through comparison to other chlorinating reagents and by the chlorination of pharmaceuticals including caffeine, lidocaine, and phenazone.
- Rogers, David A.,Bensalah, Adam T.,Espinosa, Alvaro Tomas,Hoerr, John L.,Refai, Fares H.,Pitzel, Amy K.,Alvarado, Juan J.,Lamar, Angus A.
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supporting information
p. 4229 - 4233
(2019/06/17)
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- Visible-light photocatalytic activation of N-chlorosuccinimide by organic dyes for the chlorination of arenes and heteroarenes
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A variety of arenes and heteroarenes are chlorinated in moderate to excellent yields using N-chlorosuccinimide (NCS) under visible-light activated conditions. A screening of known organic dye photocatalysts resulted in the identification of methylene green as the most efficient catalyst to use with NCS. According to mechanistic studies described within, the reaction is speculated to proceed via a single electron oxidation of NCS utilizing methylene green under visible-light photoredox pathway. The photo-oxidation of NCS amplifies the electrophilicity of the chlorine atom of the NCS, thus leading to enhanced reactivity as a chlorinating reagent with aromatic substrates.
- Rogers, David A.,Gallegos, Jillian M.,Hopkins, Megan D.,Lignieres, Austin A.,Pitzel, Amy K.,Lamar, Angus A.
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- Nickel-catalyzed cross-coupling reaction of carbamates with silylmagnesium reagents
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The C–O bonds are kinetically inert in cross-coupling reactions compared to those of carbon–halogen bonds. Thus, developing methodologies for the activation of C–O bonds in cross-coupling reactions remains a major challenge. We disclose an unprecedented nickel mediated cross-coupling of carbamates with silylmagnesium reagents that does not require the expensive silylboranes. Silylmagnesium reagents were prepared from either silyllithium or silyl iodides. This methodology is distinguished by the synthesis of trimethylsilyl coupled product and its synthetic applications. Kinetic studies and radical clock experiments revealed the rate-limiting C–O bond cleavage, half order with respect to the catalyst and a non-radical transition state.
- Murugesan, Vetrivelan,Balakrishnan, Venkadesh,Rasappan, Ramesh
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p. 293 - 298
(2019/08/12)
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- Room temperature C(sp2)-H oxidative chlorination: Via photoredox catalysis
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Photoredox catalysis has been developed to achieve oxidative C-H chlorination of aromatic compounds using NaCl as the chlorine source and Na2S2O8 as the oxidant. The reactions occur at room temperature and exhibit exclusive selectivity for C(sp2)-H bonds over C(sp3)-H bonds. The method has been used for the chlorination of a diverse set of substrates, including the expedited synthesis of key intermediates to bioactive compounds and a drug.
- Zhang, Lei,Hu, Xile
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p. 7009 - 7013
(2017/10/05)
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- Salicylic Acid-Catalyzed One-Pot Hydrodeamination of Aromatic Amines by tert-Butyl Nitrite in Tetrahydrofuran
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A significant acceleration in the hydrodeamination of in situ formed diazonium salts (from aromatic amines) has been observed in the presence of 10-mol% salicylic acid, using tetrahydrofuran as the hydrogen donor. The reaction proceeds efficiently at 20 °C for a wide range of substituted anilines, even at 10-mmol scale, without any other additive. The same protocol has been adapted to the selective deuterodeamination of some aromatic amines. Control experiments clearly show that aryl radicals are involved in the reaction mechanism. (Figure presented.).
- Felipe-Blanco, Diego,Alonso, Francisco,Gonzalez-Gomez, Jose C.
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supporting information
p. 2857 - 2863
(2017/08/23)
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- Pd-Catalyzed Decarbonylative Cross-Couplings of Aroyl Chlorides
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This report describes a method for Pd-catalyzed decarbonylative cross-coupling that enables the conversion of carboxylic acid derivatives to biaryls, aryl amines, aryl ethers, aryl sulfides, aryl boronate esters, and trifluoromethylated arenes. The success of this transformation leverages the Pd0/Brettphos-catalyzed decarbonylative chlorination of aroyl chlorides, which can then participate in diverse cross-coupling reactions in situ using the same Pd catalyst.
- Malapit, Christian A.,Ichiishi, Naoko,Sanford, Melanie S.
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supporting information
p. 4142 - 4145
(2017/08/15)
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- Degradation of one-side fully-chlorinated 1,2,3,4-tetrachloronaphthalene over Fe-Al composite oxides and its hypothesized reaction mechanism
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The degradation of 1,2,3,4-tetrachloronaphthalene (CN-27) featuring a one-side fully-chlorinated aromatic ring, was evaluated over three of the prepared rod-like Fe-Al composite oxides (FeAl-1, FeAl-5 and FeAl-10). The results showed that their reactive activities were in the order of FeAl-5 ≈ FeAl-10 ? FeAl-1, which could be attributed to their different pore structural properties and reactive sites caused by the different phase interaction between iron species and the γ-Al2O3. The generation of trichloronaphthalenes (1,2,3-TrCN and 1,2,4-TrCN, i.e. CN-13 and CN-14), dichloronaphthalenes (1,2-DiCN, 1,3-DiCN, 1,4-DiCN and 2,3-DiCN, i.e. CN-3, CN-4, CN-5 and CN-10) and monochloronaphthalenes (1-MoCN and 2-MoCN, i.e. CN-1 and CN-2) suggested the occurrence of successive hydrodechlorination reactions. The amount of CN-14 exceeded that of CN-13 from 71.5% to 77.7% across the three different systems, revealing the preferred occurrence of the first hydrodechlorination step at the β-position. This is dissimilar to the preference at the α-position observed during the dechlorination of octachloronaphthalene (CN-75) over micro/nano Fe3O4. The structural differences between one-side and two-side fully-chlorinated aromatic rings would have a pronounced impact on the reactivity of the chlorine substitution position. The major hydrodechlorination pathway was judged to be CN-27 → CN-14 → CN-4 → CN-2. Additionally, the detected 1,2,3,4,6-pentachloronaphthalene (CN-50) and 1,2,4,6/7-tetrachloronaphthalenes (CN-33/34) suggested the reverse chlorination reaction also happened while the hydrodechlorination reaction was occurring. The C-Cl bond dissociation energies (BDEs) of the parent and daughter polychlorinated naphthalene (PCN) congener were calculated using density functional theory (DFT), to achieve a deeper understanding of a different product yield distribution.
- Liu, Yalu,Lu, Huijie,Pan, Wenxiao,Li, Qianqian,Su, Guijin,Zheng, Minghui,Gao, Lirong,Liu, Guorui,Liu, Wenbin
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p. 17577 - 17585
(2017/03/31)
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- A highly efficient heterogeneous copper-catalyzed chlorodeboronation of arylboronic acids leading to chlorinated arenes
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A highly efficient heterogeneous copper-catalyzed chlorodeboronation of arylboronic acids with inexpensive N-chlorosuccinimide (NCS) was achieved in MeCN in the presence of 10 mol% of l-proline-functionalized MCM-41-immobilized copper(i) complex [MCM-41-l-proline-CuCl] under mild conditions, yielding a variety of aryl chlorides in excellent yields. This method proved to be tolerant of a broad range of functional groups and particularly useful for the conversion of electron-deficient arylboronic acids to aryl chlorides, a transformation that is inefficient without copper catalysis. This heterogeneous copper catalyst can be recovered by a simple filtration of the reaction solution and recycled for at least 10 times without any decreases in activity.
- He, Wen,Zhang, Rongli,Cai, Mingzhong
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p. 764 - 770
(2017/01/13)
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- Aromatic Monochlorination Photosensitized by DDQ with Hydrogen Chloride under Visible-Light Irradiation
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Photochlorination of aromatic substrates by hydrogen chloride with 2,3-dichloro-5,6-cyano-p-benzoquinone (DDQ) occurs efficiently to produce the corresponding monochlorinated products selectively under visible-light irradiation. The yields for the chlorination of phenol were 70 % and 18 % for p- and o-chlorophenol, respectively, without formation of further chlorinated products. The photoinduced chlorination is initiated by electron transfer from Cl- to the triplet excited state of DDQ. The radical intermediates involved in the photochemical reaction have been detected by time-resolved transient absorption measurements.
- Ohkubo, Kei,Fujimoto, Atsushi,Fukuzumi, Shunichi
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p. 996 - 999
(2016/04/20)
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- Photocatalytic activation of N-chloro compounds for the chlorination of arenes
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Photoredox catalysis activates N-chloramines and N-chloro-succinimide (NCS) for the electrophilic chlorination of arenes. The photooxidation of the nitrogen atom to a radical cation induces a positive polarization on the chlorine atom, which results in a higher reactivity in electrophilic aromatic chlorination reactions.
- Hering, Thea,K?nig, Burkhard
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p. 7821 - 7825
(2016/11/16)
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- Electrophilic aryl-halogenation using N-halosuccinimides under ball-milling
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We report here a methodology of chemo- and regio-selective aryl bromination and iodination using respective N-halosuccinimides at room temperature in the absence of any solvents, catalyst/additives under ball-milling condition. However, for chlorination ceric ammonium nitrate was used as additive. The coupled product succinimide, produced from the reactions, was recycled via regeneration of NBS. This methodology works with the electron-donor substituted or unsubstituted arenes.
- Bose, Anima,Mal, Prasenjit
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p. 2154 - 2156
(2015/03/18)
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- Electrophilic aryl-halogenation using N-halosuccinimides under ball-milling
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We report here a methodology of chemo- and regio-selective aryl bromination and iodination using respective N-halosuccinimides at room temperature in the absence of any solvents, catalyst/additives under ball-milling condition. However, for chlorination ceric ammonium nitrate was used as additive. The coupled product succinimide, produced from the reactions, was recycled via regeneration of NBS. This methodology works with the electron-donor substituted or unsubstituted arenes.
- Bose, Anima,Mal, Prasenjit
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supporting information
p. 2154 - 2156
(2014/04/03)
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- Glycinatocopper(II) complex as an efficient heterogeneous catalyst for aromatic Finkelstein reaction of aryl and heteroaryl bromides to chlorides
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Glycinatocopper(II) complex 1, readily synthesized from copper chloride and glycine was characterized by various techniques including FTIR, XRD, TGA and SEM analysis. The as-synthesized copper complex was found to be a simple and efficient catalyst for the synthesis of aryl and heteroaryl chlorides via aromatic Finkelstein reaction of aryl and heteroaryl bromides in high to excellent yields. The developed glycinatocopper(II) catalyst could easily be recovered from the reaction mixture and reused successfully for several runs without any loss in catalytic efficiency. The developed methodology represents the first example of the use of heterogeneous catalyst for the synthesis of aryl and heteroaryl chlorides via aromatic Finkelstein reaction.
- Verma, Sanny,Saran, Sandeep,Jain, Suman L.
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p. 178 - 183
(2014/02/14)
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- Iron(III)-mediated photocatalytic selective substitution of aryl bromine by chlorine with high chloride utilization efficiency
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An iron(III)-mediated photocatalytic method for the conversion of aryl, heteroaryl and polycyclic aromatic bromides to the corresponding chlorides with high selectivity has been achieved successfully. The mild reaction conditions and high chloride utilization efficiency promise a bright future for chlorination reactions. The Royal Society of Chemistry 2014.
- Wang, Ying,Li, Lina,Ji, Hongwei,Ma, Wanhong,Chen, Chuncheng,Zhao, Jincai
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supporting information
p. 2344 - 2346
(2014/03/21)
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- Aromatic substitution in ball mills: Formation of aryl chlorides and bromides using potassium peroxomonosulfate and NaX
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Aryl chlorides and bromides are formed from arenes in a ball mill using KHSO5 and NaX (X = Cl, Br) as oxidant and halogen source, respectively. Investigation of the reaction parameters identified operating frequency, milling time, and the number of milling balls as the main influencing variables, as these determine the amount of energy provided to the reaction system. Assessment of liquid-assisted grinding conditions revealed, that the addition of solvents has no advantageous effect in this special case. Preferably activated arenes are halogenated, whereby bromination afforded higher product yields than chlorination. Most often reactions are regio- and chemoselective, since p-substitution was preferred and concurring side-chain oxidation of alkylated arenes by KHSO5 was not observed. The Royal Society of Chemistry.
- Schmidt, Robert,Stolle, Achim,Ondruschka, Bernd
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p. 1673 - 1679
(2013/02/22)
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- Cu(I)/cu(II)/TMEDA, new effective available catalyst of sandmeyer reaction
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The system Cu(I)/Cu(II)/N,N,N',N'-tetramethylethylenediamine is a highly effi cient and accessible catalyst of Sandmeyer reaction. The reaction of aryldiazonium salts with chlorides, bromides cyanides, and thiocyanates of alkaline metals in the presence of this catalytic system leads to the formation of the corresponding aryl halides, nitriles, and thiocyanates in high yields.
- Sigeev, A. S.,Beletskaya, I. P.,Petrovskii, P. V.,Peregudov, A. S.
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p. 1055 - 1058,4
(2020/10/15)
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- Nucleophilic substitution of hydrogen in naphthalene by chloride (Cl -) in ionic liquids
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Nucleophilic aromatic substitution of hydrogen in non-activated aromatic ring, a very rare phenomenon in organic chemistry, is found in ionic liquids containing Cl- as anion under mild reaction conditions. The reaction may be carried out by the addition of the halogen-bonding adduct (Br 2Cl-) as nucleophile to aromatic ring carbon atom, leading to the formation of the nucleophilic substitution product.
- Shi, Shen Yi,Kong, Ai Guo,Zhao, Xin Hua,Ding, Han Ming,Yang, Fan,Shan, Yong Kui
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experimental part
p. 147 - 150
(2012/01/03)
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- Metal-free chlorodeboronation of organotrifluoroborates
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A mild and metal-free method for the chlorodeboronation of organotrifluoroborates using trichloroisocyanuric acid (TCICA) was developed. Aryl-, heteroaryl-, alkenyl-, alkynyl-, and alkyltrifluoroborates were converted into the corresponding chlorinated products in good yields. This method proved to be tolerant of a broad range of functional groups.
- Molander, Gary A.,Cavalcanti, Livia N.
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experimental part
p. 7195 - 7203
(2011/10/13)
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- Phosphonium nitrate ionic liquid catalysed electrophilic aromatic oxychlorination
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Trioctylmethylphosphonium nitrate (P8,8,8,1NO3), an ionic liquid made via a green synthesis, catalyses electrophilic aromatic chlorination of arenes with HCl and air at 80 °C. The aromatic oxychlorination is truly catalytic in nitrate, proceeds without added solvents, and uses atmospheric oxygen as oxidant. The extent of chlorination can be controlled to yield selectively mono or dichlorinated products, and the ionic liquid catalyst can be recycled. Dependence of the chlorination rate on HCl and nitrate concentrations as well as on the rate of re-oxidation of the nitrogen intermediates by air, allowed us to propose a reaction mechanism.
- Noe, Marco,Perosa, Alvise,Selva, Maurizio,Zambelli, Luca
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experimental part
p. 1654 - 1660
(2010/12/19)
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- Catalysis of the oxidative chlorination of aromatic compounds with substituted iron phthalocyanines
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Iron phthalocyanine-catalyzed oxidative chlorination of aromatic hydrocarbons using the H2O2-HCl system led to the formation of the corresponding chlorine derivatives.
- Fedorova,Kaliya,Luk'yanets,Negrimovskii
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experimental part
p. 1611 - 1613
(2009/06/28)
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- Highly reactive and regenerable fluorinating agent for oxidative fluorination of aromatics
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A newly synthesized copper aluminum fluoride of nominal composition CuAl2F8 exhibits excellent reactivity towards direct oxidative fluorination of aromatic compounds, as well as fluorodechlorination of chloroaromatics. The spent CuAl2F8 reagent can be regenerated by treatment with O2 and HF, and the fluorination process has been demonstrated to retain high conversions through 20 reaction cycles. The main advantages of this new process are safety, minimal waste, and potentially low cost.
- Janmanchi, Krishna Murthy,Dolbier Jr., William R.
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p. 349 - 354
(2013/01/03)
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- New reactivity patterns of copper(I) and other transition metal NHC complexes: application to ATRC and related reactions
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Pre-formed transition metal-NHC complex is shown to be an effective catalyst for Atom Transfer Radical Cyclisation (ATRC) reactions.
- Bull, James A.,Hutchings, Michael G.,Luján, Cristina,Quayle, Peter
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p. 1352 - 1356
(2008/09/18)
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- A remarkably simple and efficient benzannulation reaction
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(Chemical Equation Presented) On a short fuse: Although fused aromatic rings are common structural motifs in natural products, there are relatively few direct methods for the preparation of such systems from acyclic precursors. An atom-transfer radical cyclization carried out under microwave (MW) irradiation has now been developed which gives rapid access to functionalized aromatic compounds from readily available starting materials (see scheme).
- Bull, James A.,Hutchings, Michael G.,Quayle, Peter
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p. 1869 - 1872
(2008/03/12)
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- PROCESS FOR SYNTHESIS OF AROMATIC COMPOUNDS
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The present invention refers to a process for preparing a compound of the formula (I) wherein R denotes an organic radical which, together with the two carbon atoms to which it is bonded, forms a carbocyclic or heterocyclic ring; R1, R2, R3 and X, independently, denote hydrogen, halogen, nitro, cyano or an organic radical; or R1 and R2 or R2 and R3, together with the carbon atoms to which they are bonded, form a ring; which comprises exposing a compound of the formula (II) wherein R1, R2, R3 and X are defined as given above and Y and Z, independently, have one of the meanings of X; to an energy source in the presence of a catalyst system.
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Page/Page column 17-18
(2008/06/13)
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- Regioselective haloaromatization of 1,2-bis(ethynyl)benzene via halogen acids and PtCl2. Platinum-catalyzed 6-π electrocyclization of 1,2-bis(1′-haloethenyl)benzene intermediates
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Treatment of 1,2-bis(ethynyl)benzene (1) with aqueous HX (X = Br, I) in hot 3-pentanone (100-105 °C, 2 h) afforded 1,2-bis(1′-haloethenyl)benzene species 2-Br and 2-I in 98% and 95% yields, respectively. The hydrochlorination of endiyne 1 failed to proceed at elevated temperature but was implemented efficiently by PtCl2 (5 mol %) in hot 3-pentanone (100 °C, 2 h) to give 1,2-bis(1′-chloroetheny)benzene 2-Cl in 80% yield. In the presence of PtCl2 (5 mol %), these halides 2-Cl, 2-Br, and 2-I were subsequently converted to 1-halonaphthalenes 3-Cl, 3-Br, and 3-I in the mother solution via sequential 6-π electrocyclization and dehalogenation reactions. PtCl2 (5 mol %) also effected direct haloaromatization of endiyne 1 with HX (X = Cl, Br, I) and gave 1-halonaphthalenes 3-Cl, 3-Br, and 3-I in 64-71% yields. This investigation reports the scope and the regioselectivity of haloaromatization of various enediynes catalyzed by PtCl2.
- Lo, Ching-Yu,Kumar, Manyam Praveen,Chang, Hsu-Kai,Lush, Shie-Fu,Liu, Rai-Shung
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p. 10482 - 10487
(2007/10/03)
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- A novel and efficient ceric ammonium nitrate catalyzed oxidative nuclear chlorination of activated aromatic compounds by acetyl chloride
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A mild and efficient oxidative chlorination of activated aromatic compounds have been achieved in excellent yields using acetyl chloride in the presence of a catalytic amount of ceric ammonium nitrate at room temperature. However, chlorination failed to occur with deactivated aromatic rings.
- Roy, Subhas Chandra,Rana, Kalyan Kumar,Guin, Chandrani,Banerjee, Biplab
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p. 221 - 222
(2007/10/03)
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- Oxidative halogenation of aromatic compounds with metal halides and sodium bismuthate
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A new mild and efficient method for aromatic halogenation with a wide variety of halides in the presence of sodium bismuthate NaBO3 in AcOH is reported. Metal halides of groups Ia, IIa, IIIa, IVa, Va, and the first row of transition elements are suitable for this method.
- Muathen, Hussni A.
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p. 164 - 168
(2007/10/03)
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- Environmentally benign chlorination and bromination of aromatic amines, hydrocarbons and naphthols
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A simple and efficient procedure for chlorination and bromination of aromatic amines, hydrocarbons and naphthols by the action of aqueous hydrohalic acid and hydrogen peroxide is described. This environmentally clean and safe procedure involves in situ generation of the active halogen and its uncatalyzed reaction with the substrates in this study.
- Vyas, Punita V.,Bhatt, Anjani K.,Ramachandraiah, Gadde,Bedekar, Ashutosh V.
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p. 4085 - 4088
(2007/10/03)
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- Synthesis of heterocycles from the products of anionic arylation of unsaturated compounds. 7*. Products of haloarylation of acrylic acid and its esters in the synthesis of benzo[b]thiophene derivatives
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3-Chloro-2-chlorocarbonylbenzo[b]thiophenes were obtained on oxidation of Meerwein reaction products, viz. 3-aryl-2-halopropionic acids and their esters, with thionyl chloride in the presence of N-benzyl-N-methylmorpholinium chloride. Disubstituted thioureas were synthesized by the reaction of these compounds with ammonium thiocyanate and aromatic amines, and were cyclized by interaction with iodoacetic acid with the formation of 4-thiazolidinone derivatives. The same cyclization in the presence of aromatic aldehydes leads to the formation of the corresponding 5-arylidene-substituted 4-thiazolidinones.
- Obushak,Matiichuk,Martyak
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p. 878 - 884
(2007/10/03)
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- Analysis and structure prediction of chlorinated polycyclic aromatic hydrocarbons released from combustion of polyvinylchloride
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Chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs) released from combustion of polyvinylchloride (PVC) at different furnace temperatures were investigated. A laboratory-scale tube-type furnace with electric heating was utilized to control combustion conditions. Glass fabric filters and adsorbents were used to collect the combustion emissions. Following Soxhlet extraction, concentration and column chromatography purification, isomers separation, selective detection and identification of Cl-PAHs were performed on GC/MS system on the basis of retention data and mass spectra. Their quantification was accomplished by using external standard calibration technique. About 18 Cl-PAHs were determined, most of which were monochlorinated derivatives of naphthalene, biphenyl, fluorene, phenanthrene, anthracene, fluoranthene and pyrene. Only two dichlorophenanthrenes or anthracenes were identified. The possible positions of chlorine atoms attached to the aromatic rings are predicted by quantitative structure-property relationship. The levels of these compounds were in the range of 0.30-29.08 μg/g PVC. The relationship between the formation of Cl-PAHs and PAHs was discussed.
- Wang, Dongli,Xu, Xiaobai,Chu, Shaogang,Zhang, Daren
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p. 495 - 503
(2007/10/03)
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- Aromatic iodination: A new investigation on the nature of the mechanism
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Following a suggestion by the late Lennart Eberson, we have employed the ICl-HFP (HFP being hexafluoropropan-2-ol) system in iodination reactions, and found unambiguous evidence for the occurrence of an ET-mechanism of halogenation. The evidence is based on the use of 'intelligent' substrates, which make it possible to fix the boundaries between the occurrence of an ET-mechanism and of a conventional polar mechanism. In an 'intelligent' substrate, in fact, the nature of the product(s) changes significantly depending on the operating mechanism. The ICl-HFP combination is instrumental to the onset of a one-electron oxidation with electron-rich substrates, followed by halogenation. The most prominent example is that of the electron-rich substrate durene (1,2,4,5-tetramethylbenzene, DUR), when compared to mesitylene (1,3,5-trimethylbenzene, MES): with a 'conventional' iodination system (i.e., I2/ Ag+) and in common solvents, where the polar mechanism holds, durene is less reactive (kMES/kDUR = 46 ± 3), but becomes more reactive (kMES/kDUR = 0.23) in HFP with ICl, where the ET-mechanism takes over. Other substrates also support the onset of ET-pathways in HFP. Finally, a preliminary survey of a biohalogenation reaction induced by laccase indicates the modest occurrence of a polar process of iodination with a few substrates.
- Fabbrini, Maura,Galli, Carlo,Gentili, Patrizia,Macchitella, Daniele,Petride, Horia
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p. 1516 - 1521
(2007/10/03)
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- Halodediazoniations of dry arenediazonium o-benzenedisulfonimides in the presence or absence of an electron transfer catalyst. Easy general procedures to prepare aryl chlorides, bromides, and iodides
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The paper reports the results of a wide study aimed at preparing aryl chlorides 3 (19 examples), bromides 4 (19 examples), and iodides 5 (9 examples) by halodediazoniation of dry arenediazonium o-benzenedisulfonimides 1 with tetraalkylammonium halides 2. The reactions were carried out in anhydrous acetonitrile at room temperature (~20 °C) in the presence of copper powder and at 60 °C or room temperature without the catalyst. In optimal conditions the yields were from good to excellent (60 reactions, 61- 94% yield), with only a few exceptions (8 reactions, 51-55% yield). A good amount of the o-benzenedisulfonimide (7) was always recovered from the reactions and could then be reused to prepare salts 1. An interesting aspect of this research is the surprising role of the anion of o- benzenedisulfonimide (9) as an electron transfer agent.
- Barbero,Degani,Dughera,Fochi
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p. 3448 - 3453
(2007/10/03)
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- Solid-state reaction of a lead tetraacetate - Metal halide system with naphthalene under mechanical activation
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A mechanically activated solid-state reaction of halogenation of naphthalene with a Pb(OAc)4 - alkaline or alkaline-earth metal halide system was carried out to yield 1-halonaphthalene as the main reaction product and 1,4-dihalonaphthalene. The solid-state halogenation of naphthalene is more selective than a liquid-phase reaction.
- Nikishin,Sokova,Makhaev,Petrova,Ignatenko,Kapustina
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p. 1353 - 1355
(2007/10/03)
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- The impact of turbulent mixing on the oxidation of a chlorinated hydrocarbon
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Combustion of chlorinated wastes can lead to the formation of hazardous byproducts. Rates of mixing of fuel and air in combustion systems can have an impact on the composition of the byproducts. Methyl chloride and methane were burned in a turbulent diffusion flame in a combustion wind tunnel with a coflow of air. Reynolds numbers were varied from 3500 to 7200. A water- cooled sampling probe was used to obtain gas samples from within the flame at a number of locations and at various Reynolds numbers. The postflame gases and particulate matter were trapped above the flames with sorbent tubes and filters. The samples were desorbed and analyzed for aromatic species and other trace products of incomplete combustion. Destruction of the methyl chloride was essentially complete for all the Reynolds numbers that were studied. Small amounts of low molecular weight chlorinated compounds were fOUnd within the flame and in the postflame gases. The major chlorinated species in the postflame gases was chloronaphthalene. Low Reynolds number flames were found to Yield larger amounts of aromatic and chlorinated aromatic species than the high Reynolds number flames. Fluoranthene was present in greater amounts on the soot particles at lower Reynolds numbers, suggesting that the rate of mixing of reactants could have an impact on the toxicity of the combustion byproducts. Combustion of chlorinated wastes can lead to the formation of hazardous byproducts. Rates of mixing of fuel and air in combustion systems can have an impact on the composition of the byproducts. Methyl chloride and methane were burned in a turbulent diffusion flame in a combustion wind tunnel with a coflow of air. Reynolds numbers were varied from 3500 to 7200. A water-cooled sampling probe was used to obtain gas samples from within the flame at a number of locations and at various Reynolds numbers. The postflame gases and particulate matter were trapped above the flames with sorbent tubes and filters. The samples were desorbed and analyzed for aromatic species and other trace products of incomplete combustion. Destruction of the methyl chloride was essentially complete for all the Reynolds numbers that were studied. Small amounts of low molecular weight chlorinated compounds were found within the flame and in the postflame gases. The major chlorinated species in the postflame gases was chloronaphthalene. Low Reynolds number flames were found to yield larger amounts of aromatic and chlorinated aromatic species than the high Reynolds number flames. Fluoranthene was present in greater amounts on the soot particles at lower Reynolds numbers, suggesting that the rate of mixing of reactants could have an impact on the toxicity of the combustion byproducts.
- Yang, Gosu,Jones, A. Daniel,Kennedy, Ian M.
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p. 1265 - 1268
(2007/10/03)
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- Mild chlorination of aromatic compounds with tin(IV) chloride and lead tetraacetate
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SnCl4/Pb(OAc)4 acts as a safe source of Cl2 for the chlorination of aromatic compounds. A variety of aromatic compounds are effectively chlorinated with SnCl4/Pb(OAc)4 under mild conditions. The mixture is a selective chlorinating agent, particularly with polyalkylbenzenes, polycyclic aromatic compounds and anisoles.
- Muathen, Hussni A.
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p. 8863 - 8866
(2007/10/03)
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- Reaction of Aromatic and Unsaturated Compounds with the Potassium Permanganate/HCI (HBr) Acetonitrile Reagent
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Addition of hydrochloric or hydrobromic acid to a solution of potassium permanganate in acetonitrile produced a homogeneous mixture, which is suitable for laboratory chlorination or bromination, respectively. Aromatic compounds more reactive than alkylbenzenes can be chlorinated or brominated without additional catalyst. Alkenes and alkynes give the corresponding vicinal dihaloalkanes and vinyl halides. All reactions complete within two hours under mild condition (25-60 °C) with excellent to moderate yields.
- Liu, Lilian Kao,Lin, Ching-Shan
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- Peroxide Salts as Reagents in Oxidative Halogenation of Aromatic Compounds
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Chloromesitylene, chloro-p-xylene, and 1-bromonaphthalene are formed in 78, 79, and 86percent yield, respectively, under the action of the halogenating system hydrogen peroxide-hydrohalic acid-AcOH.The following aryl halides are also formed in high yields in this halogenating system: 2-bromothiophene (89 - 92percent) upon bromonation of thiophene; chlorobenzene (77 - 79percent) and iodobenzene (79 - 81percent) upon chlorination and iodination of benzene.
- Rudakova, N. I.,Erykalov, Yu. G.,Zharikova, S. M.,Dmitrieva, E. V.,Mataradze, M. S.
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p. 271 - 272
(2007/10/03)
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- Determination of the gas-phase acidities of halogen-substituted aromatic compounds using the silane-cleavage method
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The gas-phase acidities of halogen-substituted aromatic compounds have been determined in a flowing afterglow-triple quadrupole apparatus with use of the silane cleavage method developed by DePuy and co-workers [C. H. DePuy, S. Gronert, S. E. Barlow, V. M. Bierbaum and R. Damrauer, J. Am. Chem. Sec., 111, 1968 (1989)]. In this method the relative yields of siloxide ion products produced in reactions of OH- with trimethylsilyl- or phenyidimethylsilyl-substituted aromatic compounds are correlated with the difference in gas-phase acidity of the accompanying neutral products. Acidities are reported for different ring-positions in fluoro-, chloro- and bromobenzene, chloro- and bromonaphthalene and benzyl chloride. Excellent precision is achieved in most cases, with assigned uncertainties less than 23 kcal/mol. Goad agreement is obtained between the acidities determined with use of two different types of silane precursor. Halogen-substitution increases the gas-phase acidities of benzene and naphthalene by similar amounts (13-14 kcal/mol). The effects on different ring-positions in benzene and naphthalene are shown to be primarily inductive in nature, falling-off by a consistent 2.5-3.5 kcal/mol per bond separating the acidic site from the haloges-bearing carbon in the chlorine and bromine-substituted systems. Larger effects are evident in the positional acidities of fluorobenzene. The meta and pava position acidities of halobenzenes are shown to be linearly correlated with the acidities of the corresponding meta and pava halophenols, haloanilines and halotoluenes.
- Wenthold,Squires
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- The Reaction of Iodine Monochloride with Polycyclic Aromatic Compounds: Polar and Electron Transfer Pathways
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Several polycyclic aromatic hydrocarbons were treated with iodine monochloride.Although iodination is the predominant reaction of benzenoid arenes, chlorination is the sole reaction with anthracene, phenanthrene and naphthalene compounds (except for 5), whose oxidation half-wave potentials are less than 1.58 V vs Ag/Ag(+) (0.1 M).Arenes with higher potentials are unreactive.Naphthalene (9) and its derivatives with mild electron-withdrawing substituents are chlorinated; the exception (5) yields the 1-iodo product (21).The reaction is first order in substrate and second order in ICl.An electron transfer pathway involving radical cation intermediates is assumed.Ion-pair collapse of the radical cation-ICl intermediates is proposed for the chlorinations and radical-pair collapse for the iodination.
- Turner, Dean E.,O'Malley, Robert F.,Sardella, Dennis J.,Barinelli, Lucio S.,Kaul, Pushkar
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p. 7335 - 7340
(2007/10/02)
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- Ring Halogenations of Polyalkylbenzenes by Ionic Halides and Koser's Reagent
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Ring chlorinations of polyalkylbenzenes such as mesitylene have been carried out at room temperature with LiCl or NaCl and stoichiometric amounts of Koser's reagent.Solvent range from water to methylene chloride.The procedures were extended to bromination and iodination.
- Bovonsombat, Pakorn,Djuardi, Elsa,Nelis, Edward Mc
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p. 2841 - 2844
(2007/10/02)
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- Phthalocyanine compounds, production method thereof, and near infrared ray absorption materials containing the same
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A novel fluorine-containing phthalocyanine compound represented by the following formula (I): STR1 wherein Y is STR2 wherein R1 and R2 are independently a hydrogen atom or a C1-C8 alkyl group; R3 and R4 are independently a C1-C8 alkyl group; X is a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxyl group or a halogen atom; Z is a hydrogen atom, a C1-C4 alkyl group, a C1-C4 alkoxyl group, a C1-C4 alkoxycarbonyl group or a halogen atom; W is a C1-C4 alkoxyl group; e, f, g, h and j are independently an integer of 1 or 2; n is an integer of 1 to 8; and p and q are independently an integer of 1 to 6; a to d are an integer of 0 to 2 with the proviso that the sum of a to d is 1 to 8; and M is a non-metal, a metal, a metal oxide, a metal carbonyl or a metal halide, and further, a method of producing a fluorine-containing phthalocyanine compound represented by the above formula (I).
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- 1-NAPHTHALENEDIAZONIUM TETRACHLOROCUPRATE - A NEW ARYLATING REAGENT
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The conditions were worked out for the catalytic chloronaphthylation of unsaturated compounds by 1-naphthalenediazonium chloride in the Meerwein reaction.The intermediate in this process is 1-naphthalenediazonium tetrachlorocuprate, which is an effective arylating agent.The reaction of this complex salt with unsaturated compounds gave the same chloronaphthylation products but with higher yields.
- Obushak, N. D.,Ganushchak, N. I.,Lyakhovich, M. B.
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p. 1543 - 1547
(2007/10/02)
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- Electron Transfer Reactions. XIX. Outer-Sphere Electron Transfer Reactions between Hexachloroosmate(V) and Organic Compounds
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The reaction between tetraphenylphosphonium hexachloroosmate(V), a strong one-electron oxidant, and typical organic electron transfer reagents has been studied by preparative, kinetic and theoretical methods.Like tungsten hexachloride, hexachloroosmate(V) supports characteristic oxidative nuclear and/or side-chain acetoxylation of aromatic compounds in the presence of an acetate ion source.With tetramethylstannane, the reaction is first order in both reagents and shows no dependence on ->, the acetate ion source employed in this study.For 4-methoxytoluene (PMT) and naphthalene (Naph), first order behaviour in -> and is observed whereas reaction orders of 1.4 and 0.5-0.7 in -> and -1.0 and -0.5 in 2->infinite, respectively, indicate that back electron transfer competes with base/nucleophile capture of the intermediate radical cation in a mechanism involving initial, reversible electron transfer followed by a rate-determining follow-up reaction of the radical cation.This is supported in the 4-methoxytoluene case by a strong kinetic deuterium isotope effect upon the measured rate parameter, kH/kD being 4.1(2) whis is normal for this reaction type.The electron transfer rate constants for the three substrates were evaluated (tetramethylstannane 10.1, 4-methoxytoluene 16 and naphthalene 5.3 M-1s-1) and compared with values calculated by the Marcus treatment.With the assumption that the self-exchange reorganization energies, λ(PMT-cation radical/PMT) and λ(Naph-cation radical/Naph), are high, 50 and 30 kcal mol-1, respectively, the agreement is satisfactory.
- Eberson, Lennart,Nilsson, Monica
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p. 1062 - 1070
(2007/10/02)
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- Versatility of Zeolites as Catalysts for Ring or Side-Chain Aromatic Chlorinations by Sulfuryl Chloride
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Zeolites catalyze chlorination of aromatics by sulfuryl chloride SO2Cl2.It is possible by an appropriate choice of the catalyst to effect at will, with very high selectivity, either the ring or the side-chain chlorination.Zeolite ZF520 is the choice catalyst for the former, because of its high Broensted acidity.Zeolite NaX (13X) is a fine catalyst for the latter, free-radical chlorination; the reaction is best effected in the presence of a light source; the catalyst can be reused many times with no loss in activity.Both reaction modes, the ionic (ring chlorination)and the radical (side-chain substitution), are likely to occur outside of the channel network in the microporous solid.The effects of various experimental factors - such as the nature of the solvent, the reaction time and temperature, the Broensted acidity of the solid support, the presence of radical inhibitors, and the quantity of catalysts - were investigated.The procedures resulting from this study are very easy to implement in practice and are quite effective.
- Delaude, Lionel,Laszlo, Pierre
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p. 5260 - 5269
(2007/10/02)
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- Generation of Radical-cations from Naphthalene and Some Derivatives, both by Photoionization and Reaction with SO4-.: Formation and Reactions Studied by Laser Flash Photolysis
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Radical-cations from naphthalene and some derivatives have been generated in aqueous acetonitrile both by direct photolysis (with λ 248 nm light via biphotonic ionization) and via reaction with SO4-..The radical-cation reacts rapidly with the parent substrate (k ca. 1E8 dm3 mol-1 s-1) and with nucleophiles (e. g. with N3- k = 4.2*1E9 dm3 mol-1 s-1 or with water, k 4*1E4 s-1 ).The radical-cation from 1-naphthylethanoic acid undergoes rapid decarboxylation (k 5*1E5 s-1).The radical cations from 4-methyl- and 4-methoxy-phenylethanoic acid also rapidly decarboxylate to yield the corresponding benzyl radicals.
- Steenken, Steen,Warren, Cathryn J.,Gilbert, Bruce C.
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p. 335 - 342
(2007/10/02)
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