- Reactions of Aryl Diazonium Salts and Alkyl Arylazo Ethers. XI. Further Evidence for the Mechanism of Dediazoniation i Basic Alcoholic Solution
-
A comparison of the relative amounts of dediazoniation, SNAr and aryne reactions of 4-chloro-3-nitrobenzenediazonium ion with methoxide ion in CH3OH and in CD3OH confirms that the dediazoniation reaction involves hydride abstraction from the alkoxide ion by the electrophilic terminal nitrogen atom of the diazonium ion.Furthermore, the relative amounts of anionic and free-radical dediazoniation are the same in CH3OH and in CD3OH.This confirms that the partitioning between the free-radical and anionic pathway for dediazoniation is on the aryl diimide and not on the free diazonium ion.Some previously reported results on the solvent effect (methanol against ethanol) for the reaction have been reinterpreted in the light of the above conclusions.
- Broxton, Trevor J.,McLeish, Michael J.
-
-
Read Online
- Inexpensive NaX (X = I, Br, Cl) as a halogen donor in the practical Ag/Cu-mediated decarboxylative halogenation of aryl carboxylic acids under aerobic conditions
-
Versatile and practical Ag/Cu-mediated decarboxylative halogenation between readily available aryl carboxylic acids and abundant NaX (X = I, Br, Cl) has been achieved under aerobic conditions in moderate to good yields. The halodecarboxylation is shown to be an effective strategy for S-containing heteroaromatic carboxylic acid and benzoic acids with nitro, chloro and methoxyl substituents at the ortho position. A gram-scale reaction and a three-step procedure to synthesize iniparib have been performed to evaluate the practicality of this protocol. A preliminary mechanistic investigation indicates that Cu plays a vital role and a radical pathway is involved in the transformation.
- Fu, Zhengjiang,Jiang, Ligao,Zuo, Qianming,Li, Zhaojie,Liu, Yanzhu,Wei, Zhenhong,Cai, Hu
-
supporting information
p. 5416 - 5421
(2018/08/12)
-
- Induction of Axial Chirality in 8-Arylquinolines through Halogenation Reactions Using Bifunctional Organocatalysts
-
The enantioselective syntheses of axially chiral heterobiaryls were accomplished through the aromatic electrophilic halogenation of 3-(quinolin-8-yl)phenols with bifunctional organocatalysts that control the molecular conformations during successive halogenations. Axially chiral quinoline derivatives, which have rarely been synthesized in an enantioselective catalytic manner, were afforded in moderate-to-good enantioselectivities through bromination, and an analogous protocol also enabled enantioselective iodination. In addition, this catalytic reaction, which allows enantioselective control through the use of mono-ortho-substituted substrates, allowed the asymmetric synthesis of 8-arylquinoline derivatives bearing two different halogen groups in high enantioselectivities.
- Miyaji, Ryota,Asano, Keisuke,Matsubara, Seijiro
-
supporting information
p. 9996 - 10000
(2017/08/01)
-
- Efficient transposition of the sandmeyer reaction from batch to continuous process
-
The transposition of Sandmeyer chlorination from a batch to a safe continuous-flow process was investigated. Our initial approach was to develop a cascade method using flow chemistry which involved the generation of a diazonium salt and its quenching with copper chloride. To achieve this safe continuous process diazotation, a chemometric approach (Simplex method) was used and extrapolated to establish a fully continuous-flow method. The reaction scope was also examined via the synthesis of several (het)aryl chlorides. Validation and scale-up of the process were also performed. A higher productivity was obtained with increased safety.
- D'Attoma, Joseph,Camara, Titi,Brun, Pierre Louis,Robin, Yves,Bostyn, Stéphane,Buron, Frédéric,Routier, Sylvain
-
-
- PROCESS FOR THE PREPARATION OF ORGANIC HALIDES
-
The present invention provides a halo-de-carboxylation process for the preparation of organic chlorides, organic bromides and mixtures thereof, from their corresponding carboxylic acids, using a chlorinating agent selected from trichloroisocyanuric acid (TCCA), dichloroisocyanuric acid (DCCA), or combination thereof, and a brominating agent.
- -
-
Paragraph 00138
(2017/08/01)
-
- Synthetic method of aryl halide taking aryl carboxylic acid as raw material
-
A synthetic method of an aryl halide taking aryl carboxylic acid as a raw material is characterized in that a corresponding aryl halide is formed by carrying out substitution reaction on an aryl carboxylic acid compound and haloid salt MX in an organic solvent under the condition that oxygen, a silver catalyst, a copper additive and a bidentate nitrogen ligand exist, wherein M in MX represents alkali metal or alkaline earth metal, and X represents F, Cl, Br or I. Compared with a conventional aryl halide synthetic method, the synthetic method disclosed by the invention has the obvious advantages that reaction raw materials (comprising aryl carboxylic acid and MX) are cheap and easy to obtain, the using amount of a metal catalyst is small, pollution to the environment when the oxygen is used as an oxidant is the smallest, good tolerance to various functional groups on an aromatic ring is obtained, the yield is high, and the like. The synthetic method disclosed by the invention can be widely applied to synthesis in the fields of medicine, materials, natural products and the like in industry and academia.
- -
-
Paragraph 0133
(2018/01/03)
-
- A 4-chloro-3-nitroanisole method for the preparation of
-
The invention relates to a preparation method of 4-chloro-3-nitryl benzaldehyde. 4-chloro-3-nitryl benzaldehyde is prepared from 4-amino-3-nitryl benzaldehyde, sodium nitrite and hydrochloric acid as raw materials, and a metal chloride as a catalyst by reaction of a two-step one-pot method of diazotization and chlorination; particularly, the metal chloride is a mixture which is prepared from palladium chloride, cobalt chloride and cuprous chloride according to the molar ratio of (0.1-0.3) to (0.2-0.4) to 1. The specific metal catalyst is adopted in the reaction of the two-step one-pot method of diazotization and chlorination, so that the method is mild in reaction condition, high in catalytic efficiency, low in amount of the catalyst, high in yield, relatively low in cost, and suitable for industrial production; and the content of a target product is high.
- -
-
Paragraph 0030; 0031
(2016/10/10)
-
- Synthetic method of metoclopramide intermediate 4-chloro-3-nitroanisole
-
The invention discloses a synthetic method of metoclopramide intermediate 4-chloro-3-nitroanisole. The synthetic method comprises the following steps: adding 90-110ml of a concentrated phosphoric acidsolution, 80-100ml of water and 0.25mol of 4-amino-3-nitroanisole (2) into a reaction vessel, and controlling the stirring speed to be 200-230rpm; lowering the temperature of the solution to 5-9 DEG C, and slowly adding 0.24-0.25mol of potassium hydrogen sulfite to be dissolved in 100mol of water to prepare a solution; adding 200mL of the potassium hydrogen sulfitesolution into the reaction vessel, and controlling the temperature of the solution to be 6-8 DEG C and the reaction time to last for 40-50min; dissolving 0.29-0.30mol of stannous bromide in 130ml of a concentrated potassium chloridesolution, quickly adding a diazonium salt into the stannous bromide solution, and controlling the temperature of the solution to be 15-19 DEG C; standing for 3-5 hours, and gradually heating the solution to 65-70 DEG C until no gas is released; performing distillation by virtue of water vapor until no oily matter is distilled off; performing extraction by using acetone, and combining extracts; and sequentially performing washing by using a neutralizing solution and a saline solution, performing dehydration by using a dehydrating agent, and recovering acetone to obtain a yellow solid namely 4-chloro-3-nitroanisole.
- -
-
Paragraph 0014; 0015
(2016/10/31)
-
- Decarboxylative Halogenation and Cyanation of Electron-Deficient Aryl Carboxylic Acids via Cu Mediator as Well as Electron-Rich Ones through Pd Catalyst under Aerobic Conditions
-
Simple strategies for decarboxylative functionalizations of electron-deficient benzoic acids via using Cu(I) as promoter and electron-rich ones by employing Pd(II) as catalyst under aerobic conditions have been established, which lead to smooth synthesis of aryl halides (-I, Br, and Cl) through the decarboxylative functionalization of benzoic acids with readily available halogen sources CuX (X = I, Br, Cl), and easy preparation of benzonitriles from decarboxylative cyanation of aryl carboxylic acids with nontoxic and low-cost K4Fe(CN)6 under an oxygen atmosphere for the first time.
- Fu, Zhengjiang,Li, Zhaojie,Song, Yuanyuan,Yang, Ruchun,Liu, Yanzhu,Cai, Hu
-
p. 2794 - 2803
(2016/04/26)
-
- Magnesium oxide as a heterogeneous and recyclable base for the N-methylation of indole and O-methylation of phenol using dimethyl carbonate as a green methylating agent
-
This work reports a mild efficient and sustainable protocol for N-methylation of indole and O-methylation of phenol using dimethylcarbonate as an environmentally safe, non-toxic, biodegradable and green methylating agent under microwave conditions. Magnesium oxide (MgO) has been employed as a heterogeneous and recyclable base for clean N-methylation of indole and O-methylation of phenol with dimethylcarbonate. Basic properties of the fresh and recycled MgO were measured by temperature programmed desorption (CO2-TPD) analysis. The CO2-TPD runs suggested that both strong and moderately basic sites are present on the oxide, while only the moderately basic sites are responsible for the N-and O-methylation of indole and phenol, respectively, using DMC as a methylating agent. The CO2-TPD analysis showed that the basic sites on fresh and recycled MgO were comparable. The MgO was isolated by simple filtration and recycled efficiently without loss in activity and selectivity.
- Gadge, Sandip T.,Mishra, Ashish,Gajengi, Aravind L.,Shahi, Nileshkumar V.,Bhanage, Bhalchandra M.
-
p. 50271 - 50276
(2014/12/10)
-
- 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)
-
- An expeditious and environmentally benign preparation of aryl halides from aryl amines by solvent-free grinding
-
An efficient solvent-free methodology for conversion of various aryl amines into bromides and chlorides via arenediazonium tosylate salts under grinding conditions is disclosed. This new methodology not only avoids the use of strong acids and expensive reagents for diazotization-halogenation reactions, but also decreases the amount of organic waste from the reaction process.
- Moon, Mi Eun,Choi, Younghwa,Lee, Young Min,Vajpayee, Vaishali,Trusova, Marina,Filimonov, Victor D.,Chi, Ki-Whan
-
scheme or table
p. 6769 - 6771
(2011/03/17)
-
- Efficient and economic halogenation of aryl amines via arenediazonium tosylate salts
-
Arenediazonium tosylate salts have been successfully employed as a new and efficient reagent in halogenation reactions. A novel and economic protocol has been developed for the bromination and chlorination of various anilines using arenediazonium tosylate salts. A wide variety of reaction conditions were studied in acetonitrile at either room temperature or 60 °C in the presence or absence of catalyst with good to excellent yields. A surprising result showed the formation of acetanilides as a major product of aniline and methyl-substituted aniline halogenations in high yields.
- Lee, Young Min,Moon, Mi Eun,Vajpayee, Vaishali,Filimonov, Victor D.,Chi, Ki-Whan
-
experimental part
p. 7418 - 7422
(2010/10/01)
-
- 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)
-
