Xn:Harmful;90-13-1Relevant articles and documents
Method for preparing 1 - chloronaphthalene
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Paragraph 0013-0022, (2021/03/23)
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.
A Visible Light and Iron-mediated Carbocationic Route to Polysubstituted 1-Halonaphthalenes by Benzannulation using Allylbenzenes and Polyhalomethanes
Roslan, Irwan Iskandar,Zhang, Hongwei,Ng, Kian-Hong,Jaenicke, Stephan,Chuah, Gaik-Khuan
, p. 1007 - 1013 (2020/12/30)
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.).
Triptycenyl Sulfide: A Practical and Active Catalyst for Electrophilic Aromatic Halogenation Using N-Halosuccinimides
Nishii, Yuji,Ikeda, Mitsuhiro,Hayashi, Yoshihiro,Kawauchi, Susumu,Miura, Masahiro
supporting information, p. 1621 - 1629 (2020/02/04)
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.
Amplification of Trichloroisocyanuric Acid (TCCA) Reactivity for Chlorination of Arenes and Heteroarenes via Catalytic Organic Dye Activation
Rogers, David A.,Bensalah, Adam T.,Espinosa, Alvaro Tomas,Hoerr, John L.,Refai, Fares H.,Pitzel, Amy K.,Alvarado, Juan J.,Lamar, Angus A.
supporting information, p. 4229 - 4233 (2019/06/17)
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.
Visible-light photocatalytic activation of N-chlorosuccinimide by organic dyes for the chlorination of arenes and heteroarenes
Rogers, David A.,Gallegos, Jillian M.,Hopkins, Megan D.,Lignieres, Austin A.,Pitzel, Amy K.,Lamar, Angus A.
, (2019/08/12)
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.
Nickel-catalyzed cross-coupling reaction of carbamates with silylmagnesium reagents
Murugesan, Vetrivelan,Balakrishnan, Venkadesh,Rasappan, Ramesh
, p. 293 - 298 (2019/08/12)
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.
Degradation of one-side fully-chlorinated 1,2,3,4-tetrachloronaphthalene over Fe-Al composite oxides and its hypothesized reaction mechanism
Liu, Yalu,Lu, Huijie,Pan, Wenxiao,Li, Qianqian,Su, Guijin,Zheng, Minghui,Gao, Lirong,Liu, Guorui,Liu, Wenbin
, p. 17577 - 17585 (2017/03/31)
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.
Room temperature C(sp2)-H oxidative chlorination: Via photoredox catalysis
Zhang, Lei,Hu, Xile
, p. 7009 - 7013 (2017/10/05)
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.
Salicylic Acid-Catalyzed One-Pot Hydrodeamination of Aromatic Amines by tert-Butyl Nitrite in Tetrahydrofuran
Felipe-Blanco, Diego,Alonso, Francisco,Gonzalez-Gomez, Jose C.
supporting information, p. 2857 - 2863 (2017/08/23)
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.).
A highly efficient heterogeneous copper-catalyzed chlorodeboronation of arylboronic acids leading to chlorinated arenes
He, Wen,Zhang, Rongli,Cai, Mingzhong
, p. 764 - 770 (2017/01/13)
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.
