88-06-2Relevant academic research and scientific papers
Mechanistic Study of the Peroxyoxalate System in Completely Aqueous Carbonate Buffer
Augusto, Felipe A.,Bartoloni, Fernando H.,Pagano, Ana Paula E.,Baader, Wilhelm J.
, p. 309 - 316 (2020/11/30)
The peroxyoxalate reaction is one of the most efficient chemiluminescence transformations, with emission quantum yields of up to 50%; additionally, it is widely utilized in analytical and bioanalytical assays. Although the real reason for its extremely hi
Efficient demethylation of aromatic methyl ethers with HCl in water
Bomon, Jeroen,Bal, Mathias,Achar, Tapas Kumar,Sergeyev, Sergey,Wu, Xian,Wambacq, Ben,Lemière, Filip,Sels, Bert F.,Maes, Bert U. W.
supporting information, p. 1995 - 2009 (2021/03/26)
A green, efficient and cheap demethylation reaction of aromatic methyl ethers with mineral acid (HCl or H2SO4) as a catalyst in high temperature pressurized water provided the corresponding aromatic alcohols (phenols, catechols, pyrogallols) in high yield. 4-Propylguaiacol was chosen as a model, given the various applications of the 4-propylcatechol reaction product. This demethylation reaction could be easily scaled and biorenewable 4-propylguaiacol from wood and clove oil could also be applied as a feedstock. Greenness of the developed methodversusstate-of-the-art demethylation reactions was assessed by performing a quantitative and qualitative Green Metrics analysis. Versatility of the method was shown on a variety of aromatic methyl ethers containing (biorenewable) substrates, yielding up to 99% of the corresponding aromatic alcohols, in most cases just requiring simple extraction as work-up.
Activator free, expeditious and eco-friendly chlorination of activated arenes by N-chloro-N-(phenylsulfonyl)benzene sulfonamide (NCBSI)
Misal, Balu,Palav, Amey,Ganwir, Prerna,Chaturbhuj, Ganesh
supporting information, (2021/01/04)
N-Chloro-N-(phenylsulfonyl)benzene sulfonamide (NCBSI) has been explored for the first time as a chlorinating reagent for direct chlorination of various activated arenes and heterocycles without any activator. A comparative in-silico study was performed to determine the electrophilic character for NCBSI and commercially available N-chloro reagents to reveal the reactivity on a theoretical viewpoint. The reagent was prepared by an improved method avoiding the use of hazardous t-butyl hypochlorite. This reagent was proved to be very reactive compared to other N-chloro reagents. The precursor of the reagent N-(phenylsulfonyl)benzene sulfonamide was recovered from aqueous spent, which can be recycled to synthesize NCBSI. The eco-friendly protocol was equally applicable for the synthesis of industrially important chloroxylenol as an antibacterial agent.
Mechanistic Studies on the Salicylate-Catalyzed Peroxyoxalate Chemiluminescence in Aqueous Medium
Cabello, Maidileyvis C.,Souza, Glalci A.,Bello, Liena V.,Baader, Wilhelm J.
, p. 28 - 36 (2020/01/08)
The peroxyoxalate reaction is one of the most efficient chemiluminescence transformations known and the only system occurring by an intermolecular chemically initiated electron exchange luminescence (CIEEL) mechanism with confirmed high quantum yields. The peroxyoxalate chemiluminescence (PO-CL) is mainly studied in anhydrous organic medium; however, for bioanalytical application, it should be performed in aqueous media. In the present work, we study the peroxyoxalate system in a binary 1,2-dimethoxyethane/water mixture with bis(2,4,6-trichlorophenyl) oxalate (TCPO), bis(4-methylphenyl) oxalate (BMePO) and bis[2-(methoxycarbonyl)phenyl] oxalate (DMO), catalyzed by sodium salicylate, in the presence of rhodamine 6G as activator. Reproducible kinetic results are obtained for all systems; emission decay rate constants depend on the salicylate as well as hydrogen peroxide concentration, and the occurrence of a specific base catalysis is verified. Although singlet quantum yields determined are lower than in anhydrous media in comparable conditions, they are still considerably high and adequate for analytical applications. The highest singlet quantum yields are obtained for the “ecologically friendly” derivative DMO indicating that this derivative might be the most adequate substrate for the use of the peroxyoxalate system in bioanalytical applications.
Kinetic studies on 2,6-lutidine catalyzed peroxyoxalate chemiluminescence in organic and aqueous medium: Evidence for general base catalysis
Augusto, Felipe A.,Bartoloni, Fernando H.,Cabello, Maidileyvis C.,dos Santos, Ana Paula F.,Baader, Wilhelm J.
, (2019/07/31)
The peroxyoxalate reaction, base catalyzed perhydrolysis of activated aromatic oxalate esters in the presence of chemiluminescence activators, has widespread analytical and bioanalytical applications and is one of the most efficient chemiluminescence transformations known. We report here a kinetic study on this reaction using 2,6-lutidine as catalyst in organic (1,2-dimethoxyethane) and aqueous medium. In both media, experimental conditions can be designed which lead to reproducible results important for analytical applications. Observed rate constants (determined by observing the light emission intensity as well as absorbance variation due to phenol releases) show dependence on both the 2,6-lutidine and the hydrogen peroxide concentration, indicating their participation in the rate-limiting step of the transformation. The rate constants obtained from these kinetic studies proved to be at least one order of magnitude higher in water than in 1,2-dimethoxyethane as solvent. Kinetic experiments designed to distinguish between three different types of catalysis (nucleophilic, specific base and general base catalysis) clearly indicate that the role of 2,6-lutidine in this reaction is as general base catalyst in water as well as most likely in organic medium.
Method for producing high purity 2, 4 - dichlorophenol
-
Paragraph 0115-0124, (2019/07/04)
The invention provides a method for producing high purity 2, 4 - dichlorophenol, including: (1) heating and melting the raw materials, the mixed catalyst is added in the raw material, wherein the feedstock is phenol, O-phenol or [...] in at least one of, the mixed catalyst is phenyl sulfide, mixture of ferric chloride and trifluoromethanesulfonic acid; (2) to maintain the temperature of the material is 40 - 100 °C, to the material to carry out chlorination chlorinating agent is filled in the catalytic reaction to obtain 2, 4 - dichlorophenol crude product, the chlorinating agent is chlorine or sulfuryl chloride in at least one of; (3) to said 2, 4 - dichlorophenol crude melt crystallization, to obtain 2, 4 - dichlorophenol product. In this invention the states the chlorizating agent can be a chloride, can also be chlorine, the two can achieve higher conversion rate of raw materials, the application in the catalytic chlorination reaction the crude product obtained without rectification, only through the melt crystallization to obtain the purity 99% of the 2, 4 - dichlorophenol product.
Synthesis of substituted phenols via hydroxylation of arenes using hydrogen peroxide in the presence of hexaphenyloxodiphosphonium triflate
Khodaei, Mohammad Mehdi,Alizadeh, Abdolhamid,Hezarkhani, Hadis Afshar
, p. 878 - 882 (2018/11/06)
A mild and efficient protocol for the synthesis of phenols from arenes has been developed using aqueous hydrogen peroxide as an oxidizing agent and hexaphenyloxodiphosphonium triflate as a promoter. The reactions were carried out with the simple procedure in EtOH-H2O at room temperature in short reaction times.
In Situ Formed IIII-Based Reagent for the Electrophilic ortho-Chlorination of Phenols and Phenol Ethers: The Use of PIFA-AlCl3 System
Nahide, Pradip D.,Ramadoss, Velayudham,Juárez-Ornelas, Kevin A.,Satkar, Yuvraj,Ortiz-Alvarado, Rafel,Cervera-Villanueva, Juan M. J.,Alonso-Castro, ángel J.,Zapata-Morales, Juan R.,Ramírez-Morales, Marco A.,Ruiz-Padilla, Alan J.,Deveze-álvarez, Martha A.,Solorio-Alvarado, César R.
, p. 485 - 493 (2018/02/09)
A new and in situ formed reagent generated by mixing PIFA {bis[(trifluoroacetoxy)iodobenzene]} and AlCl3 was introduced in the organic synthesis for the direct and highly regioselective ortho-chlorination of phenols and phenol ethers. An efficient electrophilic chlorination for these electron-rich arenes as well as the scope of the reaction are described herein. An easy, practical, and open-flask reaction allowed us to introduce a chlorine atom, which is a highly important functional group in organic synthesis. The reproducibility of our method has been demonstrated on gram-scale by carrying out the reaction in 6-bromo-2-naphthol. This halogenation reaction also proceeds in excellent conditions by first preparing the iodine(III)-based chlorinating reagent. Our new chlorinating reagent can be stored at least for two weeks at 4 °C without losing its reactivity.
Selective water-based oxychlorination of phenol with hydrogen peroxide catalyzed by manganous sulfate
Xin, Hongchuan,Yang, Shilei,An, Baigang,An, Zengjian
, p. 13467 - 13472 (2017/03/11)
An efficient method for the selective oxychlorination of phenol to 2,4-dichlorophenol catalyzed by manganous(ii) sulfate is developed using hydrogen chloride as a chlorinating source, hydrogen peroxide as an oxidant and water as a solvent. The catalyst has high activity and selectivity under mild conditions. The products are automatically isolated from aqueous solution, which also contains the catalyst at the end of the reaction, and hence product separation and catalyst recycling are both simple in this system. The performance of manganous(ii) sulfate with the oxidative chlorinating system HCl/H2O2 indicates that this is a promising synthetic method for the manufacture of various 2,4-dichlorophenol derivatives.
Regioselective C-H chlorination: Towards the sequential difunctionalization of phenol derivatives and late-stage chlorination of bioactive compounds
Gao, Chao,Li, Hongchen,Liu, Miaochang,Ding, Jinchang,Huang, Xiaobo,Wu, Huayue,Gao, Wenxia,Wu, Ge
, p. 46636 - 46643 (2017/10/16)
We have developed a protocol for the auxillary directed C-H chlorination of phenol derivatives using catalytic amounts of palladium acetate that is amenable to the late-stage chlorination of diflufenican and estrone. The 2-pyridine group allows for a highly efficient palladium-catalyzed chlorination and sequential ortho C-H functionalization reaction of phenol derivatives to produce a variety of symmetrical and unsymmetrical 2,4,6-trisubstituted phenols.
