62247-77-2Relevant academic research and scientific papers
Continuous Synthesis and Separation ofp-Bromobenzyl Bromide Using Atom-Efficient Bromination ofp-Bromotoluene without Any Organic Effluent: Potential for Green Industrial Practice
Sancheti, Sonam V.,Yadav, Ganapati D.
, p. 2071 - 2080 (2021/09/13)
This work focuses on the bromination ofp-bromotoluene (PBT) using different brominating agents such as liquid Br2, NaBr-NaBrO3, NaBr-NaBrO3-NaCl, NaBr-H2O2, and HBr-H2O2. NaBr-NaBrO3-NaCl is an eco-friendly brominating agent obtained from a bromine recovery plant. Both NaBr-NaBrO3and NaBr-NaBrO3-NaCl were found to be nonhazardous and efficient brominating agents. Pure NaBr-NaBrO3resulted in the best PBT conversion with 79.7% Br atom efficiency in water and 98.2% average Br atom efficiency using dichloroethane as a solvent. Dichloroethane is de facto no longer used in the US and Europe and is not eco-friendly; the process with water as a solvent is the best. The substrate to active bromine molar ratio of 3:1 was found to be sufficient to get the maximum selectivity ofp-bromobenzyl bromide (PBBB). The low-temperature crystallization method was used for separation cum purification of the product. Unreacted PBT was recycled along with the dibromo byproduct obtained. The dibromo product, which was built up gradually in the reaction mixture over 10 successive batches, was converted back into PBBB/PBT through NaBH4treatment of the mother liquor. This continuous process is highly sustainable and produces zero organic waste, making it potentially attractive toward green industrial implementation.
One-pot synthesis of 3,5-diaryl substituted-1,2,4-oxadiazoles using gem -dibromomethylarenes
Vinaya, Kambappa,Chandrashekara, Ganganahalli K.,Shivaramu, Prasanna D.
, p. 690 - 696 (2019/09/06)
1,2,4-Oxadiazole is one of the most promising heterocyclic ring systems in medicinal chemistry. In the present paper, we report the method for an efficient one-pot synthesis of 3,5-diaryl substituted 1,2,4-oxadiazoles using a two-component reaction of gem-dibromomethylarenes with amidoximes in good yields. In this method, gem-dibromomethylarenes are used as benzoic acid equivalents for the efficient synthesis of aryl-substituted 1,2,4-oxadiazoles. It is anticipated that this methodology will have versatile applications in the practical syntheses of various molecules of both medicinal and material chemistry importance.
Visible-Light-Driven Oxidative Mono- and Dibromination of Benzylic sp 3 C-H Bonds with Potassium Bromide/Oxone at Room Temperature
Zhao, Mengdi,Li, Meiqi,Lu, Wenjun
supporting information, p. 4933 - 4939 (2018/12/14)
Benzylic sp 3 C-H bonds have been successfully brominated with potassium bromide by using Oxone as an oxidant in water/dichloromethane under visible light at room temperature. Toluene, ethylbenzene and other alkylbenzenes bearing an electron-withdrawing group, such as Br, Cl, COMe, CO 2 Et, CO 2 H, CN or NO 2, provide the corresponding benzylic monobromides in good to excellent yields in this reaction. Dibromides can also be produced in the presence of excess potassium bromide in a prolonged reaction time. Control of the illuminance of visible light (~500 lux) is crucial to achieving both high yield and high selectivity in these brominations. Mono- and difluorides can be conveniently prepared through nucleophilic substitutions of the benzylic bromides with potassium fluoride.
Method for preparing benzyl bromide
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Paragraph 0076-0078, (2017/10/05)
The invention provides a method for preparing benzyl bromide. The method comprises the following steps: by taking bromine released from a redox reaction between bromates and negative bromide ions in the presence of an acid as a bromine source in an organic solvent, carrying out a benzyl radical substitution reaction with a methylbenzene compound shown as a formula I under initiation of an initiator, thereby obtaining a corresponding benzyl bromide compound shown a formula II, wherein in the formula II, m represents the number of Br and is equal to 1 or 2; when m is equal to 1, the formula II shows a benzyl monobromo compound; and when m is equal to 2, the formula II shows a benzyl dibromo compound. The reaction is carried out in an organic solvent, the initiator is combined and used, the radical substitution reaction is high in selectivity and wide in substrate application range, the substituent group replacing methylbenzene may be an electron-withdrawing group or an electron-donating group and can give extremely high yield on strong electron-donating groups (such as methoxy group). Moreover, the method disclosed by the invention is also applicable to preparation of benzyl dibromo compounds, and the product yield is high.
Rasta resin-triphenylphosphine oxides and their use as recyclable heterogeneous reagent precursors in halogenation reactions
Xia, Xuanshu,Toy, Patrick H.
supporting information, p. 1397 - 1405 (2014/07/22)
Heterogeneous polymer-supported triphenylphosphine oxides based on the rasta resin architecture have been synthesized, and applied as reagent precursors in a wide range of halogenation reactions. The rasta resin-triphenylphosphine oxides were reacted with either oxalyl chloride or oxalyl bromide to form the corresponding halophosphonium salts, and these in turn were reacted with alcohols, aldehydes, aziridines and epoxides to form halogenated products in high yields after simple purification. The polymersupported triphenylphosphine oxides formed as a byproduct during these reactions could be recovered and reused numerous times with no appreciable decrease in reactivity.
Thiol-activated gem-dithiols: A new class of controllable hydrogen sulfide donors
Zhao, Yu,Kang, Jianming,Park, Chung-Min,Bagdon, Powell E.,Peng, Bo,Xian, Ming
supporting information, p. 4536 - 4539 (2015/01/08)
A class of novel thiol-activated H2S donors has been developed on the basis of the gem-dithiol template. These donors release H2S in the presence of cysteine or GSH in aqueous solutions as well as in cellular environments.
Deep cavitands featuring functional acetal-based walls
Degardin, Melissa,Busseron, Eric,Kim, Dang-A.,Ajami, Dariush,Rebek, Julius
, p. 11850 - 11852 (2013/01/16)
The synthesis of deep cavitands with functionalized acetals as a fourth-wall is described. Recognition properties and stabilities of the complexes of two representative cavitands with aliphatic, aromatic, carbocyclic and adamantane guests were evaluated b
Microwave-assisted benzyl mono- and dibromination in diethyl carbonate as environmentally friendly alternative to radical bromination in carbon tetrachloride
Pingali, Subramanya R. K.,Upadhyay, Sunil K.,Jursic, Branko S
experimental part, p. 928 - 933 (2011/05/15)
An environmentally friendly benzyl mono- and di-bromination synthetic procedure was developed that is superior to the classic carbon tetrachloride bromination procedure in both reaction time and isolated yield. This new reaction was performed in diethyl carbonate as reaction media using microwave instead of conventional heating. Both the solvent and the brominating reagent N-bromosuccinimide (prepared from succinimide obtained from the reaction mixture) are recyclable. Practically, the preparation of our target compounds was completed in less than two hours. The Royal Society of Chemistry.
Electrochemical method for the preparation of dibromomethyl, bis(bromomethyl), and bis(dibromomethyl) arenes
Kulangiappar,Karthik,Kulandainathan, M. Anbu
scheme or table, p. 2304 - 2309 (2009/12/06)
Electrochemical bromination of alkyl aromatic compounds by two-phase electrolysis yields the corresponding α,α-dibrominated products. The reaction has been carried out in a single-compartment electrochemical cell using aqueous sodium bromide (40-50%), containing a catalytic amount of HBr as electrolyte, and chloroform, containing an alkyl aromatic compound, as the organic phase with a Pt plate as anode at 10-15C. Two-phase electrolysis results in high yields (70-90%) of dibromomethyl, bis(bromomethyl), and bis(dibromomethyl) arenes, depending upon the charge passed.
Process for thermal benzylic bromination
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, (2008/06/13)
A process for thermal benzylic bromination of a wide variety of benzylic compounds is described. Bromine is used as the bromination agent. Moderate temperatures are employed and the process can be used to produce in relatively pure form either mono- or di
