- PhICl2is activated by chloride ions
-
A study on the potential activating role of pyridine in the electrophilic chlorination of anisole by PhICl2has led to the discovery that soluble sources of chloride ions activate PhICl2in the reaction at catalytic loadings, greatly increasing the rate of chlorination. It is further shown that presence of chloride increases the rate of decomposition of PhICl2into PhI and Cl2. The specific mechanism by which chloride induces electrophilic chlorination and decomposition of PhICl2remains an open question.
- Tania,Poynder, Tiffany B.,Kaur, Aishvaryadeep,Barwise, Lachlan,Houston, Sevan D.,Nair, Akshay J.,Clegg, Jack K.,Wilson, David J. D.,Dutton, Jason L.
-
supporting information
p. 11986 - 11991
(2021/09/06)
-
- Oxidative Photochlorination of Electron-Rich Arenes via in situ Bromination
-
Electron-rich arenes are oxidatively photochlorinated in the presence of catalytic amounts of bromide ions, visible light, and 4CzIPN as organic photoredox catalyst. The substrates are brominated in situ in a first photoredox-catalyzed oxidation step, followed by a photocatalyzed ipso-chlorination, yielding the target compounds in high ortho/para regioselectivity. Dioxygen serves as a green and convenient terminal oxidant. The use of aqueous hydrochloric acid as the chloride source reduces the amount of saline by-products.
- Düsel, Simon Josef Siegfried,K?nig, Burkhard
-
supporting information
p. 1491 - 1495
(2019/04/30)
-
- Organophotochemical SNAr Reactions of Mildly Electron-Poor Fluoroarenes
-
C–F functionalization of arenes with a range of alcohol and pyrazole nucleophiles has been achieved without the need for metal catalysts or highly electron-poor substrates. Treatment of fluoroarenes with alcohols or pyrazoles and DDQ under irradiation by blue LED light provides the corresponding substituted products. The procedure is complementary to classical SNAr chemistry which generally requires basic reaction conditions and high temperatures, and provides products under non-basic conditions at ≈ 40 °C.
- Burton, Jonathan W.,Genovino, Julien,Lian, Yajing,Monck, Nat,Sheridan, Thomas,Yayla, Hatice G.
-
supporting information
p. 2766 - 2770
(2020/05/18)
-
- Dehydroxyalkylative halogenation of C(aryl)-C bonds of aryl alcohols
-
We herein report Cu mediated side-directed dehydroxyalkylative halogenation of aryl alcohols. C(aryl)-C bonds of aryl alcohols were effectively cleaved, affording the corresponding aryl chlorides, bromides and iodides in excellent yields. Aryl alcohols could serve as both aromatic electrophilic and radical synthetic equivalents during the reaction.
- Liu, Mingyang,Zhang, Zhanrong,Liu, Huizhen,Wu, Tianbin,Han, Buxing
-
supporting information
p. 7120 - 7123
(2020/07/14)
-
- Efficient Electrocatalysis for the Preparation of (Hetero)aryl Chlorides and Vinyl Chloride with 1,2-Dichloroethane
-
Although the application of 1,2-dichloroethane (DCE) as a chlorinating reagent in organic synthesis with the concomitant release of vinyl chloride as a useful byproduct is a fantastic idea, it still presents a tremendous challenge and has not yet been achieved because of the harsh dehydrochlorination conditions and the sluggish C?H chlorination process. Here we report a bifunctional electrocatalysis strategy for the catalytic dehydrochlorination of DCE at the cathode simultaneously with anodic oxidative aromatic chlorination using the released HCl as the chloride source for the efficient synthesis of value-added (hetero)aryl chlorides. The mildness and practicality of the protocol was further demonstrated by the efficient late-stage chlorination of bioactive molecules.
- Liang, Yujie,Lin, Fengguirong,Adeli, Yeerlan,Jin, Rui,Jiao, Ning
-
supporting information
p. 4566 - 4570
(2019/02/14)
-
- Amplification of Trichloroisocyanuric Acid (TCCA) Reactivity for Chlorination of Arenes and Heteroarenes via Catalytic Organic Dye Activation
-
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.
-
supporting information
p. 4229 - 4233
(2019/06/17)
-
- Visible-light photocatalytic activation of N-chlorosuccinimide by organic dyes for the chlorination of arenes and heteroarenes
-
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.
-
-
- Search for a photoinduced (site-selective) cleavage of the Ar-Cl bond in dichloroanisoles
-
The site-selective cleavage of an Ar-X bond in polyhalogenated aromatics is an important tool in synthetic planning especially when more than one identical halogen atom is present. An alternative to the usual metal-catalyzed cleavage is represented by photochemistry although only a few examples have been reported. We then investigated the feasibility of the site-selective photodechlorination of some dichloroanisoles through a combined experimental and computational study. In the case of 2,4-dichloroanisole, selective detachment of the chlorine atom at the ortho position with respect to the OMe group was observed upon photohomolysis (in cyclohexane) or photoheterolysis (in MeOH) of the Ar-Cl bond. In the latter case, 5-chloro-2-methoxy-1,1′-biphenyl was exclusively formed upon reaction of the resulting phenyl cation with benzene. The substitution of an OH group for a OMe group was detrimental since a lower photoreactivity resulted with no improvement in the selectivity.
- Raviola, Carlotta,Fagnoni, Maurizio
-
p. 107 - 117
(2018/02/06)
-
- Room temperature C(sp2)-H oxidative chlorination: Via photoredox catalysis
-
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
-
p. 7009 - 7013
(2017/10/05)
-
- Benzene C-H Etherification via Photocatalytic Hydrogen-Evolution Cross-Coupling Reaction
-
Aryl ethers can be constructed from the direct coupling between the benzene C-H bond and the alcohol O-H bond with the evolution of hydrogen via the synergistic merger of photocatalysis and cobalt catalysis. Utilizing the dual catalyst system consisting of 3-cyano-1-methylquinolinum photocatalyst and cobaloxime, intermolecular etherification of arenes with various alcohols and intramolecular alkoxylation of 3-phenylpropanols with formation of chromanes are accomplished. These reactions proceed at remarkably mild conditions, and the sole byproduct is equivalent hydrogen gas.
- Zheng, Yi-Wen,Ye, Pan,Chen, Bin,Meng, Qing-Yuan,Feng, Ke,Wang, Wenguang,Wu, Li-Zhu,Tung, Chen-Ho
-
supporting information
p. 2206 - 2209
(2017/05/12)
-
- Mechanistic insight into the thermal 1,3-chlorine migrations of N-chloroacetanilides under neutral conditions
-
The mechanistic insight of the thermal 1,3-chlorine migration reactions of N-chloroacetanilides under neutral conditions has been investigated. The results indicate that the 1,3-chorinemigration reaction is initiated by the radical reaction of the homocleavage of the Cl-N bond and subsequent radical combination of the Cl-C bond on the aromatic rings. The radical mechanism was verified by the thermal rearrangement of Nchloro- N-(4-methylphenyl)acetamide in cumene. After generation of hydrochloric acid in the radical mechanism, the migrations occurred through the acid-catalyzed rearrangement as well as the acid-catalyzed Orton reaction. The current results provide a comprehensive understanding on the mechanistic insights in the Orton reaction under different conditions.
- Cheng, Baoxiang,Xu, Jiaxi
-
p. 518 - 525
(2017/05/01)
-
- A highly efficient heterogeneous copper-catalyzed chlorodeboronation of arylboronic acids leading to chlorinated arenes
-
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
-
p. 764 - 770
(2017/01/13)
-
- PhPOCl2as a potent catalyst for chlorination reaction of phenols with PCl5
-
Phenols are easily converted to the corresponding aryl chlorides by using phosphorus pentachloride (PCl5) and a catalytic amount of phenylphosphonic dichloride (PhPOCl2), which is a new efficient method for synthesis of aryl chloride in good yields.
- Wu, Jiang,Zhou, Junpeng,Shi, Yalei,Zhu, Jintao
-
supporting information
p. 1619 - 1624
(2016/10/09)
-
- Aromatic Monochlorination Photosensitized by DDQ with Hydrogen Chloride under Visible-Light Irradiation
-
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
-
p. 996 - 999
(2016/04/20)
-
- Halogenase-Inspired Oxidative Chlorination Using Flavin Photocatalysis
-
Chlorine gas or electropositive chlorine reagents are used to prepare chlorinated aromatic compounds, which are found in pharmaceuticals, agrochemicals, and polymers, and serve as synthetic precursors for metal-catalyzed cross-couplings. Nature chlorinates with chloride anions, FAD-dependent halogenases, and O2 as the oxidant. A photocatalytic oxidative chlorination is described based on the organic dye riboflavin tetraacetate mimicking the enzymatic process. The chemical process allows within the suitable arene redox potential window a broader substrate scope compared to the specific activation in the enzymatic binding pocket. Chlorination of arenes with chloride anions: The photochemical analogue of the enzymatic chlorination of Flavin-adenine dinucleotide (FAD)-dependent halogenases is possible in the presence of riboflavin, air, acetic acid, and blue light (see scheme; RFT=riboflavin tetraacetate).
- Hering, Thea,Mühldorf, Bernd,Wolf, Robert,K?nig, Burkhard
-
supporting information
p. 5342 - 5345
(2016/04/26)
-
- Story of an Age-Old Reagent: An Electrophilic Chlorination of Arenes and Heterocycles by 1-Chloro-1,2-benziodoxol-3-one
-
By the use of 1-chloro-1,2-benziodoxol-3-one, an age-old reagent, the practical and efficient chlorination method is achieved. This hypervalent iodine reagent is amenable not only to the chlorination of nitrogen-containing heterocycles but also to selected classes of arenes, BODIPY dyes, and pharmaceuticals. In addition, the advantages, such as easy preparation and recyclable, air- and moisture-stable, in combination with the success in a gram-scale experiment grant this reagent great potential for industrial application.
- Wang, Mengzhou,Zhang, Yanyan,Wang, Tao,Wang, Chao,Xue, Dong,Xiao, Jianliang
-
supporting information
p. 1976 - 1979
(2016/06/01)
-
- Eco-compatible zeolite-catalysed continuous halogenation of aromatics
-
A completely eco-compatible halogenation reaction of arenes has been developed allowing high conversions (>95%) of iodobenzene with nearly 100 kg iodobenzene converted per kgcat in one day. Several solid acids, zeolites being the most promising, have been successfully tested in the chlorination reaction of iodobenzene by using trichloroisocyanuric acid (TCCA), a green chlorination agent. H-?BEA zeolites were found to be the most active catalysts for this model halogenation reaction. A strong structure-activity relationship could be established by thorough characterisation (SEM, BET, XRD, FTIR) of various synthetic zeolites. Indeed, nano-sized ?BEA zeolites and more specifically nanosponge-like ?BEA crystals exhibited the highest catalytic performance with a conversion up to 100% and a selectivity toward monochlorinated products up to 98%. Finally, the gained knowledge was applied to set-up an eco-compatible continuous flow halogenation process of different aromatics catalysed by H-?BEA zeolites.
- Losch,Kolb,Astafan,Daou,Pinard,Pale,Louis
-
p. 4714 - 4724
(2016/09/04)
-
- Photocatalytic activation of N-chloro compounds for the chlorination of arenes
-
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
-
p. 7821 - 7825
(2016/11/16)
-
- Sono-bromination of aromatic compounds based on the ultrasonic advanced oxidation processes
-
A novel, mild "sono-halogenation" of various aromatic compounds with potassium halide was investigated under ultrasound in a biphasic carbon tetrachloride/water medium. The feasibility study was first undertaken with the potassium bromide and then extended to chloride and iodide analogues. This methodology could be considered as a new expansion of the ultrasonic advanced oxidation processes (UAOPs) into a synthetic aspect as the developed methodology is linked to the sonolytic disappearance of carbon tetrachloride. Advantages of the present method are not only that the manipulation of the bromination is simple and green, but also that the halogenating agents used are readily available, inexpensive, and easy-handling.
- Fujita, Mitsue,Lévêque, Jean-Marc,Komatsu, Naoki,Kimura, Takahide
-
p. 247 - 251
(2015/06/08)
-
- Methylation of phenol and its derivatives with dimethyl carbonate in the presence of Mn2(CO)10, W(CO)6, and Co2(CO)8
-
Aryl methyl ethers were synthesized by reactions of phenol, substituted phenols, and α- and β-naphthols with dimethyl carbonate in the presence of manganese, tungsten, and cobalt carbonyls. Optimal reactant and catalyst ratios and reaction conditions were found to ensure selective formation of aryl methyl ethers.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
-
p. 330 - 334
(2015/05/04)
-
- Gold-Catalyzed Proto- and Deuterodeboronation
-
A mild gold-catalyzed protodeboronation reaction, which does not require acid or base additives and can be carried out in "green" solvents, is described. As a result, the reaction is very functional-group-tolerant, even to acid- and base-sensitive functional groups, and should allow for the boronic acid group to be used as an effective traceless directing or blocking group. The reaction has also been extended to deuterodeboronations for regiospecific ipso-deuterations of aryls and heteroaryls from the corresponding organoboronic acid. Based on density functional theory calculations, a mechanism is proposed that involves nucleophilic attack of water at boron followed by rate-limiting B-C bond cleavage and facile protonolysis of a Au-σ-phenyl intermediate.
- Barker, Graeme,Webster, Stacey,Johnson, David G.,Curley, Rachel,Andrews, Matthew,Young, Paul C.,MacGregor, Stuart A.,Lee, Ai-Lan
-
p. 9807 - 9816
(2015/11/03)
-
- Palauchlor: A practical and reactive chlorinating reagent
-
Unlike its other halogen atom siblings, the utility of chlorinated arenes and (hetero)arenes are twofold: they are useful in tuning electronic structure as well as acting as points for diversification via cross-coupling. Herein we report the invention of a new guanidine-based chlorinating reagent, CBMG or "Palauchlor", inspired by a key chlorospirocyclization en route to pyrrole imidazole alkaloids. This direct, mild, operationally simple, and safe chlorinating method is compatible with a range of nitrogen-containing heterocycles as well as select classes of arenes, conjugated π-systems, sulfonamides, and silyl enol ethers. Comparisons with other known chlorinating reagents revealed CBMG to be the premier reagent.
- Rodriguez, Rodrigo A.,Pan, Chung-Mao,Yabe, Yuki,Kawamata, Yu,Eastgate, Martin D.,Baran, Phil S.
-
supporting information
p. 6908 - 6911
(2014/06/09)
-
- Practical and metal-free electrophilic aromatic halogenation by interhalogen compounds generated in situ from N-halosuccinimide and catalytic TMSCL
-
Halomonochloride compounds (ClCl, BrCl, ICl) generated in situ from N-halosuccinimide and catalytic chlorotrimethylsilane (TMSCl, 0.1 equiv) can efficiently halogenate aromatic compounds to give halogenated products in good to excellent yields and selectivities. The reaction can be carried out at room temperature or at lower temperatures, requires only one hour, is practical to apply to a wide range of substrates, and provides a simple access to a variety of haloarene compounds. Georg Thieme Verlag Stuttgart New York.
- Maibunkaew, Tapanee,Thongsornkleeb, Charnsak,Tummatorn, Jumreang,Bunrit, Anon,Ruchirawat, Somsak
-
supporting information
p. 1769 - 1775
(2014/08/05)
-
- Arenium ions are not obligatory intermediates in electrophilic aromatic substitution
-
Our computational and experimental investigation of the reaction of anisole with Cl2 in nonpolar CCl4 solution challenges two fundamental tenets of the traditional SEAr (arenium ion) mechanism of aromatic electrophilic substitution. Instead of this direct substitution process, the alternative addition-elimination (AE) pathway is favored energetically. This AE mechanism rationalizes the preferred ortho and para substitution orientation of anisole easily. Moreover, neither the S EAr nor the AE mechanisms involve the formation of a σ-complex (Wheland-type) intermediate in the rate-controlling stage. Contrary to the conventional interpretations, the substitution (SEAr) mechanism proceeds concertedly via a single transition state. Experimental NMR investigations of the anisole chlorination reaction course at various temperatures reveal the formation of tetrachloro addition by-products and thus support the computed addition-elimination mechanism of anisole chlorination in nonpolar media. The important autocatalytic effect of the HCl reaction product was confirmed by spectroscopic (UV-visible) investigations and by HCl-augmented computational modeling.
- Galabov, Boris,Koleva, Gergana,Simova, Svetlana,Hadjieva, Boriana,Schaefer III, Henry F.,Schleyer, Paul Von Ragué
-
p. 10067 - 10072
(2014/08/05)
-
- Amino acid intercalated layered double hydroxide catalyzed chemoselective methylation of phenols and thiophenols with dimethyl carbonate
-
Sixteen different amino acids are intercalated into Mg-Al layered double hydroxides (LDHs) by the reconstruction method and are characterized by powder XRD and FT-IR. The intercalated amino acid-LDHs (AA-LDHs) are used as catalysts for chemoselective O-methylation of phenol and S-methylation of thiophenol with dimethyl carbonate (DMC) as a green methylating agent. The intercalation behavior of various amino acids is influenced by various structural features of amino acids, namely, carbon chain length, structure, and physicochemical properties. In particular, amino acids possessing a hydrophobic side-chain show higher catalytic activity. A suitable reaction mechanism is proposed. The catalyst can also be recycled.
- Subramanian, Thirumeni,Dhakshinamoorthy, Amarajothi,Pitchumani, Kasi
-
p. 7167 - 7170
(2013/12/04)
-
- Metal and H2O2 free aerobic oxidative aromatic halogenation with [RNH3+] [NO3-]/HX and [BMIM(SO3H)][NO3)x(X)y] (X = Br, Cl) as multifunctional ionic liquids
-
Novel multifunctional ionic liquids (ILs) are generated by addition of HBr or HCl to alkylammonium nitrates ([RNH3+] [NO 3-]) and to 3-methyl-1-(butyl-4-sulfonyl)imidazolium nitrate ([BMIM(SO3H)][NO3]). The resulting [RNH 3+] [NO3-]/HX and mono (3-methyl-1-(butyl-4-sulfonyl)imidazolium) monohalogenide mononitrate ([BMIM(SO3H)][NO3)x(X)y] (X = Br, Cl)) systems act as solvent and promoter for aerobic oxidative halogenation of arenes under mild conditions in high yields that can be repeated over several cycles.
- Prebil, Rok,Laali, Kenneth K.,Stavber, Stojan
-
supporting information
p. 2108 - 2111
(2013/06/05)
-
- Mechanistic insight into halide oxidation by non-heme iron complexes. Haloperoxidase versus halogenase activity
-
This work presents the first detailed study on mechanistic aspects of halide oxidation by non-heme iron complexes. We show that while iron(iii)-hydroperoxo complexes oxidise halides via oxygen atom transfer, the corresponding iron(iv)-oxo complex reacts via electron transfer. This journal is The Royal Society of Chemistry 2013.
- Vardhaman, Anil Kumar,Barman, Prasenjit,Kumar, Suresh,Sastri, Chivukula V.,Kumar, Devesh,De Visser, Sam P.
-
p. 10926 - 10928
(2013/11/19)
-
- The oxidative halogenations of arenes in water using hydrogen peroxide and halide salts over an ionic catalyst containing sulfo group and hexafluorotitanate
-
An ionic compound, bis[1-methyl-3-(3′-sulfopropyl)imidazolium] hexafluorotitanate (1), was proved to be the efficient and recyclable catalyst for the oxidative halogenations of arenes in water using H2O 2 as the oxidant and halide salts as the halogenation sources. The mono-halogenated products were obtained selectively by this method. The synergetic catalytic effect coming from the two incorporated functionalities of SO3H and [TiF6]2- was manifested in 1. The halogenation rate catalyzed by 1 was in the ranking of NaBr NaCl > KI. The UV-vis and FT-IR analyses indicated that the successful formation and regeneration of the active peroxo-Ti species (1A) with the aid of proton acid guaranteed the recycling uses of 1.
- Wang, Ling,Wang, Sa-Sa,Vo-Thanh, Giang,Liu, Ye
-
-
- Antimony(V) chloride as an efficient reagent for deprotection of methyl ethers
-
This paper proposes a new and efficient method for the deprotection of methyl ethers using antimony pentachloride at ambient temperature. The procedure described here is a facile and practical method for the removal of the methyl group from aryl and benzyl methyl ethers. High selectivity was observed for the removal of the methyl group from dimethoxyarenes. The notable advantages of this protocol are mild reaction conditions, high yields, and the facility of workup procedure. The mechanism of the ether cleavage is proposed to explain this new reaction. Georg Thieme Verlag Stuttgart New York.
- Saadati, Fariba,Meftah-Booshehri, Hamid
-
p. 1702 - 1706
(2013/09/02)
-
- Halogenation and DNA cleavage via thermally stable arenediazonium camphorsulfonate salts
-
A series of stable arenediazonium camphorsulfonate salts (2a-2j) were synthesized by simple diazotization of several aromatic amines in the presence of sodium nitrite and camphorsulfonic acid. All the new arenediazonium camphorsulfonates, which were characterized by multinuclear (1H and 13C) NMR, IR, DSC, and X-ray diffraction analysis (2e and 2f) provide unambiguous proof for the molecular structures of 2e and 2f. The efficient application of these salts in halogenation reactions was studied in solvent and solvent-free conditions and the DNA cleavage activity was also assessed. These arenediazonium camphorsulfonate salts are noticed as efficient DNA cleaving agents.
- Vajpayee, Vaishali,Moon, Mi Eun,Lee, Sunmi,Ravikumar, Sambandam,Kim, Hyunuk,Ahn, Byungchan,Choi, Seoyoon,Hong, Soon Ho,Chi, Ki-Whan
-
p. 3511 - 3517
(2013/04/23)
-
- Formation of iron(III) meso-chloro-isoporphyrin as a reactive chlorinating agent from oxoiron(IV) porphyrin π-cation radical
-
Iron(III) isoporphyrin, a tautomer of porphyrin with a saturated meso carbon, is one of the isoelectronic forms of oxoiron(IV) porphyrin π-cation radical, which is known as an important reactive intermediate of various heme enzymes. The isoporphyrin has been believed to be incapable of catalyzing oxygenation and oxidation reactions. Here, we report that an oxoiron(IV) porphyrin π-cation radical can be converted to iron(III) meso-chloro- isoporphyrin in the presence of trifluoroacetic acid and chloride ion. More importantly, this study shows the first evidence that iron(III) meso-chloro-isoporphyrin is an excellent reactive agent for chlorinating aromatic compounds and olefins. The results of this study suggest that the mechanism involves electrophilic chlorination of substrate with iron(III) meso-chloro-isoporphyrin.
- Cong, Zhiqi,Kurahashi, Takuya,Fujii, Hiroshi
-
supporting information; experimental part
p. 4469 - 4472
(2012/04/23)
-
- Aromatic substitution in ball mills: Formation of aryl chlorides and bromides using potassium peroxomonosulfate and NaX
-
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
-
p. 1673 - 1679
(2013/02/22)
-
- Radiolabeling of aromatic compounds using K[*Cl]Cl and OXONE
-
We report a novel labeling method for the rapid radiochlorination of aromatic compounds using no-carrier-added short-half-life radioactive chloride ions ([38,39Cl]Cl- and [34mCl]Cl-) and OXONE (Sigma-Aldrich, Japan) as an oxidation reagent. The reaction of radioactive chloride ions with anisole in the presence of OXONE gave a mixture of p-[*Cl]chloroanisole and o-[*Cl]-chloroanisole, with a radiochemical conversion yield of more than 85% (not decay corrected) and selectivity of 7:3, within 10 min. Regioselective radioactive chlorination was achieved by chlorodestannylation of tributylstannyl compounds to afford the corresponding radiochlorinated compounds (p-chloroanisole and m-chloroanisole) in satisfactory radiochemical yields (80-95% and 46-65%, respectively). Copyright
- Takada, Yuuki,Hanyu, Masayuki,Nagatsu, Kotaro,Fukumura, Toshimitsu
-
p. 383 - 386,4
(2020/08/24)
-
- Iridium-catalyzed dehydrogenative decarbonylation of primary alcohols with the liberation of syngas
-
A new iridium-catalyzed reaction in which molecular hydrogen and carbon monoxide are cleaved from primary alcohols in the absence of any stoichiometric additives has been developed. The dehydrogenative decarbonylation was achieved with a catalyst generated in situ from [Ir(coe)2Cl]2 (coe=cyclooctene) and racemic 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (rac-BINAP) in a mesitylene solution saturated with water. A catalytic amount of lithium chloride was also added to improve the catalyst turnover. The reaction has been applied to a variety of primary alcohols and gives rise to products in good to excellent yields. Ethers, esters, imides, and aryl halides are stable under the reaction conditions, whereas olefins are partially saturated. The reaction is believed to proceed by two consecutive organometallic transformations that are catalyzed by the same iridium(I)-BINAP species. First, dehydrogenation of the primary alcohol to the corresponding aldehyde takes place, which is then followed by decarbonylation to the product with one less carbon atom.
- Olsen, Esben P. K.,Madsen, Robert
-
supporting information
p. 16023 - 16029
(2013/02/22)
-
- Trichloroisocyanuric acid in 98% sulfuric acid: A superelectrophilic medium for chlorination of deactivated arenes
-
Trichloroisocyanuric acid (TCCA) reacts with arenes and its reactivity is highly affected by the acid strength of the reaction medium. Deactivated arenes are efficiently chlorinated by TCCA in H2SO4. Our results, along with DFT calculations and 13C NMR spectrometry suggest the formation of a monoprotonated TCCA superelectrophile as the reactive species that can efficiently transfer electrophilic Cl+ to even very weak nucleophiles, such as m-dinitrobenzene.
- Mendo?a, Gabriela Fonseca,Senra, M?nica Rufino,Esteves, Pierre M.,De Mattos, Marcio C.S.
-
experimental part
p. 176 - 181
(2012/04/04)
-
- The use of sodium chlorate/hydrochloric acid mixtures as a novel and selective chlorination agent
-
Sodium chlorate/hydrochloric acid mixtures were used to chlorinate activated arenes and the α-position of ketones. This chlorination method was used to produce selectively mono-, di-, and trichlorinated compounds by controlling the molarity of sodium chlorate. This reagent proved to be much more efficient and easier to handle than chlorine gas.
- Moon, Byung Seok,Choi, Han Young,Koh, Hun Yeong,Chi, Dae Yoon
-
experimental part
p. 472 - 476
(2011/12/04)
-
- Layered double hydroxide-supported l-methionine-catalyzed chemoselective o-methylation of phenols and esterification of carboxylic acids with dimethyl carbonate: A "green" protocol
-
" Chemical equation presented" Simple methodology: A layered double hydroxide-supported L-methionine (LDH-Met) catalyst is designed in a simple methodology to explore its synthetic utility in biologically relevant reactions. The organocatalyst is characterized by FT-IR, TGA/DTA, powder XRD, and EDX spectroscopic techniques. This material has been successfully utilized for the preparation of aryl methyl ethers and esters from the corresponding phenols and carboxylic acids, respectively, in moderate to high yields (see scheme).
- Dhakshinamoorthy, Amarajothi,Sharmila, Alagarsamy,Pitchumani, Kasi
-
supporting information; experimental part
p. 1128 - 1132
(2010/06/13)
-
- Phosphonium nitrate ionic liquid catalysed electrophilic aromatic oxychlorination
-
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
-
experimental part
p. 1654 - 1660
(2010/12/19)
-
- Copper-catalyzed chlorination of functionalized arylboronic acids
-
"Chemical Equation Presented" A mild, efficient, Cu(I)-catalyzed method for the conversion of arylboronic acids to aryl chlorides Is reported. This method is particularly useful for the conversion of electron-deficient arylboronic acids to aryl chlorides, a transformation that is inefficient In the absence of Cu catalysis.
- Wu, Hong,Hynes Jr., John
-
supporting information; experimental part
p. 1192 - 1195
(2010/04/27)
-
- Discovery of novel and potent benzhydryl-tropane trypanocides highly selective for Trypanosoma cruzi
-
A benzhydryl tropinone oxime that is potently toxic to Trypanosoma cruzi has been previously identified. An SAR investigation determined that no part of the original compound was superfluous and all early SAR probes led to significant drops in activity. The only alteration that could be achieved without loss of activity was replacement of the aryl chloride substituent with chloro homologues. This led to the discovery of a trifluoromethyl-containing analogue with an EC50 against T. cruzi of 30 nM and a cytotoxicity selectivity index of over 1000 relative to rat skeletal myoblast L-6 cells.
- Holloway,Parisot,Novello,Watson,Armstrong,Thompson,Street,Baell
-
supporting information; experimental part
p. 1816 - 1818
(2010/06/21)
-
- Synthesis and reactivity of fluorous and nonfluorous aryl and alkyl iodine(III) dichlorides: New chlorinating reagents that are easily recycled using biphasic protocols
-
Fluorous aryl and alkyl iodine(III) dichlorides of the formulas (R fn(CH2)3)2C6H 3ICl2 (Rfn ) CF3(CF 2)n-1; n ) 8 for 3,5-disubstituted and n ) 6, 8, 10 for 2,4-disubstituted) and RfnCH2ICl2 (n ) 8, 10) are prepared in 71-98% yields by reactions of Cl2 and the corresponding fluorous iodides. These are effective reagents for the conversions of cyclooctene to trans-1,2-dichlorocyclooctene, anisole to 4-chloro- and 2-chloroanisole, 4-tert-butylphenol to 2-chloro-4-tert-butylphenol, PhCOCH 2COPh to PhCOCHClCOPh, and PhCOCH3 to PhCOCH2Cl and PhCOCHCl2 (CH3CN, rt to 40°C, 100-64% conversions). The chlorinated products and fluorous iodide coproducts are easily separated by organic/fluorous liquid/liquid biphase workups. The latter are obtained in 97-90% yields and reoxidized with Cl2. Analogous chlorinations are conducted with 3-Cl2IC6H4COOH (16) and 4,4'-Cl2IC6H4C6H 4ICl2. With the former, the products and coproduct 3-IC6H4COOH (91-85% recoveries) are easily separated by organic/aqueous NaHCO3 liquid/ liquid biphase workups. The coproduct from the latter, 4,4'-IC6H4C6H4I, is insoluble in common organic solvents, allowing separation by liquid/solid phase workups (91-89% recoveries). The effect of the structure of the iodine(III) dichloride upon reactivity is analyzed in detail. The fluorous systems with Rf8 substituents are generally superior, but 16 is more reactive and gives higher selectivities.
- Podgorsek, Ajda,Jurisch, Markus,Stavber, Stojan,Zupan, Marko,Iskra, Jernej,Gladysz, John A.
-
body text
p. 3133 - 3140
(2009/08/15)
-
- Microwave-assisted methylation of phenols with tetramethylammonium chloride in the presence of K2CO3 or Cs2CO3
-
We have evaluated the potential of using tetramethylammonium chloride (Me4NCl) as an alternative methylating agent for phenols under microwave-assisted conditions. Its chemical behavior was tested in a reaction with 2-naphthol in the presence of various bases and solvents. The method was then applied in 1,2-dimethoxyethane or toluene under heterogeneous conditions for the O-methylation of a series of phenolic compounds. We found that many simple phenols can be methylated in the presence of K2CO3, whereas some other less-reactive phenols require the presence of the more reactive Cs2CO3.
- Mara?, Nenad,Polanc, Slovenko,Ko?evar, Marijan
-
experimental part
p. 11618 - 11624
(2009/04/05)
-
- Chlorination of aromatics with trichloroisocyanuric acid (TCICA) in bronsted-acidic imidazolium ionic liquid [BMIM(SO3H)][OTf]: An economical, green protocol for the synthesis of chloroarenes
-
A survey study on electrophilic chlorination of aromatics with trichloroisocyanuric acid (TCICA) in Bronsted-acidic imidazolium ionic liquid [BMIM(SO3H)][OTf] is reported. The reactions are performed under very mild conditions (at ~50°C) and give good to excellent yields, depending on the substrates. Chemoselectivity for mono- v. dichlorination can be tuned by changing the arene-to-TCICA ratio and the reaction time. The survey study and competitive experiments suggest that triprotonated/protosolvated TCICA is a selective/moderately reactive transfer-chlorination electrophile. Density functional theory was used as guide to obtain further insight into the nature of the chlorination electrophile and the transfer-chlorination step. CSIRO 2007.
- Hubbard, Abigail,Okazaki, Takao,Laali, Kenneth K.
-
p. 923 - 927
(2008/03/17)
-
- Natural kaolinitic clay: A remarkable catalyst for highly regioselective chlorination of arenes with Cl2 or SO2Cl2
-
Natural kaolinitic clay containing transition metals such as Fe and Ti in its lattice has been found to exhibit unusual regioselectivity in the liquid-phase chlorination of arenes with either Cl2 or SO 2Cl2 as the chlorinating agent para-Chlorinated products are predominant for most of the substrates with an exceptional case of ortho-selectivity for the chlorination of aniline.
- Jayachandran,Phukan, Prodeep,Daniel, Thomas,Sudalai
-
p. 972 - 975
(2007/10/03)
-
- 4′-Alkoxyl substitution enhancing the anti-mitotic effect of 5-(3′,4′,5′-substituted)anilino-4-hydroxy-8-nitroquinazolines as a novel class of anti-microtubule agents
-
Mitosis inhibitors are powerful anticancer drugs. Based on a novel anti-microtubule agent of 5-(4′-methoxy)anilino-4-hydroxy-8-nitroquinazoline, a series of 5-(3′,4′,5′-substituted)anilino-4-hydroxy-8- nitroquinazolines were designed and synthesized to investigate the effect of the substitution on the inhibitory activity against mitotic progression of tumor cells. The large alkoxyl substitution on the 4′-position of 5-anilino ring is beneficial for the potency. The 5-(3′,4′,5′-trimethoxy)anilino-8-nitroquinazoline (1h) displays an overwhelming activity in arresting the cells at the G2/M phase, providing a promising new template for further development of potent microtubule-targeted anti-mitotic drugs.
- Jin, Yi,Zhou, Zu-Yu,Tian, Wei,Yu, Qiang,Long, Ya-Qiu
-
p. 5864 - 5869
(2007/10/03)
-
- Microwave-assisted methylation of carboxylic acids and phenolic compounds with dimethyl-carbonate under solvent-free condition
-
Phenolic compounds and carboxylic acids are methylated with dimethyl carbonate in the presence of a catalytic amount of BF3· OEt2, DBU, or KOH, in good to excellent yields under microwave irradiation and solvent-free conditions.
- Rajabi, Fatemeh,Saidi, Mohammad R.
-
p. 4179 - 4188
(2007/10/03)
-
- A simple, efficient and regioselective oxychlorination of aromatic compounds using ammonium chloride and oxone
-
A simple, efficient, mild and regioselective method for oxychlorination of aromatic compounds is reported. The electrophilic substitution of chlorine generated in situ from NH4Cl as a chlorine source and oxone as an oxidant is reported for the first time.
- Narender,Mohan, K.V.V. Krishna,Srinivasu,Kulkarni,Raghavan
-
p. 1335 - 1338
(2007/10/03)
-
- Paradigm confirmed: The first use of ionic liquids to dramatically influence the outcome of chemical reactions
-
It has been an unproven paradigm that the choice of which ionic liquid to use in a chemical reaction can have a dramatic effect on the outcome of that chemical reaction. We demonstrate, for the first time, that the reaction of toluene and nitric acid in three different ionic liquids gives rise to three completely different products in high yield. Furthermore, ionic liquids can catalyze these reactions with the only byproduct being water.
- Earle, Martyn J.,Katdare, Suhas P.,Seddon, Kenneth R.
-
p. 707 - 710
(2007/10/03)
-
- Catalytic process for regiospecific chlorination of alkanes, alkenes and arenes
-
The present invention provides a process for regiospecific chlorination of an aromatic or aliphatic compound with a chlorine source comprising a metal chloride and other than Cl2and SO2Cl2in presence of hypervalent iodine catalyst and in acidic medium.
- -
-
Page column 5-6
(2008/06/13)
-
- OOxidative bromination of activated aromatic compounds using aqueous nitric acid as an oxidant
-
Oxidative bromination of activated aromatic compounds using alkali metal bromide salts and aqueous nitric acid to the corresponding bromo-derivatives is achieved in a liquid-liquid, two-phase system under ambient conditions. Nitric acid offers a dual function of an oxidant as well as a proton donor, which is essential for oxidative bromination using metal bromide salts. Bromination as well as chlorination could be accomplished with this simple system.
- Joshi, Ashutosh V.,Baidossi, Mubeen,Mukhopadhyay, Sudip,Sasson, Yoel
-
p. 568 - 570
(2013/09/02)
-