100-11-8Relevant articles and documents
Microreactor-mediated benzylic bromination in concentrated solar radiation
Kim, Young Joon,Jeong, Myung Jin,Kim, Ji Eun,In, Insik,Park, Chan Pil
, p. 1653 - 1656 (2015)
Sunlight-induced bromination of benzylic compounds was conducted in a capillary microreactor, resulting in mono-brominated compounds with yields of up to 94%. These reactions can be considered to be eco-friendly since they were carried out without an artificial light source or additional temperature control. In addition, up to 257.9mmol could be produced daily using cost-effective molecular bromine, which leads to potential improvement of industrial processes.
An efficient and fast method for the preparation of benzylic bromides
Lee, Jong Chan,Hwang, Eui Yong
, p. 2959 - 2963 (2004)
A mixture of triphenylphosphine and N-bromosuccinimide system is found to promote efficient conversion of benzylic alcohols into benzylic bromides under microwave irradiation conditions.
Preparation and properties of a novel solution of hydrogen bromide (HBr) in 1,4-dioxane: An alternative reagent to HBr gas without protic solvents
Nishio, Yuya,Mifune, Ryota,Sato, Taisuke,Ishikawa, Shin-ich,Matsubara, Hiroshi
, p. 1190 - 1193 (2017)
A solution of hydrogen bromide (HBr) in 1,4-dioxane was prepared and investigated for its ability to brominate alcohols, and hydrobrominate alkenes. This study revealed that the brominating ability of this HBr/1,4-dioxane solution is equal or superior to that of hydrobromic acid or HBr in acetic acid. The solution of HBr in 1,4-dioxane is robust, exhibiting no decomposition of the solvent, and retaining 97% of its original concentration, when kept at ?25 °C for 30 days. This solution is a liquid alternative to HBr gas without protic solvents.
Direct oxidative conversion of methylarenes into aromatic nitriles
Tsuchiya, Daisuke,Kawagoe, Yuhsuke,Moriyama, Katsuhiko,Togo, Hideo
, p. 4194 - 4197 (2013)
A variety of methylarenes were successfully converted into the corresponding aromatic nitriles in good to moderate yields by the treatment with NBS or DBDMH in the presence of a catalytic amount of AIBN or BPO, followed by the reaction with molecular iodine in aq NH3 in a one-pot procedure. The present reaction is a useful and practical transition-metal-free method for the preparation of aromatic nitriles from methylarenes.
Polymeric ionic liquids: A strategy for preparation of novel polymeric materials
Farzin, Manoochehr,Nosratzadegan, Keyvan,Azarnia, Jamshid,Ferdosi, Mohammad
, p. 1211 - 1218 (2015)
A novel polymeric ionic liquid (PIL), bearing high C-N and N-N content, potentially suitable for new safe energetic materials and catalyst supports was introduced. The PIL was prepared by way of radical co-polymerisation of 1-vinyl-3-p-nitrobenzylimidazol
Carbon-Halogen Bonding Studies. Halogen Redistribution Reactions between Alkyl or Acetyl Halides and Tri-n-butyltin Halides
Friedrich, Edwin C.,Abma, Charles B.
, p. 1367 - 1371 (1980)
The equilibrium positions have been determined for the halogen redistribution reactions of tri-n-butyltin halides with a variety of structurally different types of alkyl halides and with acetyl halides.These have been related through the reaction ΔGo values to carbon-halogen bond dissociation energy differences.It is suggested that the trends observed in the latter may provide evidence for the existence of a small steric bond weakening effect in the order C-I > C-Br > C-Cl bonds on going from methyl to primary, secondary, and tertiary alkyl halides.On the other hand, with the 2,3-? bond containing allyl, benzyl, and propargyl halides , α-haloacetones, and haloacetonitriles, there may be some type of electronic carbon-halogen bond strengthening effect which lies in order C-I > C-Br > C-Cl.Finally, for the acetyl halides, the data are in agreement with increases in bond strengths resulting from ? contributions being in the order C-Cl > C-Br > C-I.
Facile conversion of alcohols into their bromides and iodides by N-bromo and N-iodosaccharins/triphenylphosphine under neutral conditions
Firouzabadi, Habib,Iranpoor, Nasser,Ebrahimzadeh, Farzaneh
, p. 1771 - 1775 (2006)
N-Bromo and N-iodosaccharins in the presence of triphenylphosphine convert alcohols into the corresponding bromides and iodides in good to excellent yields at room temperature under neutral conditions.
N-bromosuccinimide: A facile reagent for the oxidation of benzylic alcohols to aldehydes
Adimurthy, Subbarayappa,Patoliya, Paresh U.
, p. 1571 - 1577 (2007)
The oxidation of benzylic alcohols to aldehydes using N-bromosuccinimide (NBS) under ambient conditions without use of a transition-metal catalyst has been described. Copyright Taylor & Francis Group, LLC.
HOMOLYTIC DISPLACEMENT AT CARBON VI. SYNTHESIS OF TRICHLOROETHYLARENES FROM BENZYLCOBALOXIMES
Bougeard, Peter,Gupta, B. Dass,Johnson, Michael D.
, p. 211 - 219 (1981)
Benzylbis(dimethylglyoximato)pyridinecobalt(III) reacts with bromotrichloromethane at from 50 to 90 deg C in chloroform to give good yields of trichloroethylbenzene, which are higher when imidazole is present in the reaction mixture.Methyl- and polymethyl-substituted benzylbis(dimethylglyximato)pyridinecobalt(III) complexes give higher yields of the corresponding trichloroethylarenes (85-90percent), whereas 4-chlorobenzylbis(dimethylglyoximato)pyridinecobalt(III) only gives the 4-nitro-trichloroethylarene when imidazole is present during the reaciton.Similar reactions were observed with benzylcobaloximes and trichloromethanesulphonyl chloride both thermally and under irradiation by tungsten lamps through all-pyrex apparatus.The reactions are interpreted as a direct attack of the trichloromethyl radical on the α-carbon of the benzyl ligand.
Catalytic Bromination of Alkyl sp3C-H Bonds with KBr/Air under Visible Light
Zhao, Mengdi,Lu, Wenjun
, p. 5264 - 5267 (2018)
Alkyl sp3C-H bonds of cycloalkanes and functional branch/linear alkanes have been successfully brominated with KBr using air or O2 as an oxidant at room temperature to 40 °C. The reactions are carried out in the presence of catalytic NaNO2 in 37% HCl (aq)/solvent under visible light, combining aerobic oxidations and photochemical radical processes. For various alkane substrates, CF3CH2OH, CHCl3, or CH2Cl2 is employed as an organic solvent, respectively, to enhance the efficiency of bromination.
Environmentally benign electrophilic and radical bromination 'on water': H2O2-HBr system versus N-bromosuccinimide
Podgor?ek, Ajda,Stavber, Stojan,Zupan, Marko,Iskra, Jernej
, p. 4429 - 4439 (2009)
A H2O2-HBr system and N-bromosuccinimide in an aqueous medium were used as a 'green' approach to electrophilic and radical bromination. Several activated and less activated aromatic molecules, phenylsubstituted ketones and styrene were efficiently brominated 'on water' using both systems at ambient temperature and without an added metal or acid catalyst, whereas various non-activated toluenes were functionalized at the benzyl position in the presence of visible light as a radical activator. A comparison of reactivity and selectivity of both brominating systems reveals the H2O2-HBr system to be more reactive than NBS for benzyl bromination and for the bromination of ketones, while for electrophilic aromatic substitution of methoxy-substituted tetralone it was higher for NBS. Also, higher yields of brominated aromatics were observed when using H2O2-HBr 'on water'. Bromination of styrene reveals that not just the structure of the brominating reagent but the reaction conditions: amount of water, organic solvent, stirring rate and interface structure, play a key role in defining the outcome of bromination (dibromination vs bromohydroxylation). In addition, mild reaction conditions, a straightforward isolation procedure, inexpensive reagents and a lower environment impact make aqueous brominating methods a possible alternative to other reported brominating protocols.
Efficient organic transformations mediated by ZrOCl28H 2O in Water
Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Heidari, Mahdieh
, p. 1470 - 1482 (2011)
Operationally simple and environmentally benign methods for some organic transformations comprising reductive coupling of sulfonyl chlorides, chemoselective deoxygenation of sulfoxides, and halogenation of alcohols mediated by ZrOCl28H2O/MX in water have been developed.
A new diphenylphosphinite ionic liquid (IL-OPPh2) as reagent and solvent for highly selective bromination, thiocyanation or isothiocyanation of alcohols and trimethylsilyl and tetrahydropyranyl ethers
Iranpoor, Nasser,Firouzabadi, Habib,Azadi, Roya
, p. 5531 - 5534 (2006)
A new diphenylphosphinite ionic liquid (IL-OPPh2) is introduced. This ionic liquid is used as both a reagent and a solvent to convert alcohols and trimethylsilyl and tetrahydropyranyl (THP) ethers into their corresponding alkyl bromides, thiocyanates or isothiocyanates in the presence of Br2 and SCN- at 80 °C. In this ionic liquid, bromination and thiocyanation of alcohols occurs highly selectively in the presence of trimethylsilyl and THP-ethers and also between different classes of alcohols. The use of this ionic liquid allows easy separation of the desired products from the phosphinate by-product.
Arylmethyl radicals from arylmethoxybromodiazirines
Moss, Robert A.,Fu, Xiaolin
, p. 3353 - 3356 (2004)
(Chemical Equation Presented) Photolytic decompositions of 3-arylmethoxy-3-bromodiazirines afford arylmethyl radicals by homolyses of the diazirines' excited states.
Benzylic Bromination-Acetoxylation of Toluenes by Bromide Ion Catalyzed Thermal Decomposition of Peroxydisulfate in Acetic Acid in the Presence of Acetate Ions
Citterio, Attilio,Santi, Roberto,Pagani, Anselmo
, p. 4925 - 4927 (1987)
Side-chain bromination and acetoxylation of alkylaromatics by halide ion induced decomposition of potassium peroxydisulfate in acetic acid have been studied by product analysis techniques.Catalytic amounts of lithium bromide in the presence of sodium acetate were found effective in promoting benzylic bromination, followed by conversion to the corresponding benzyl acetates by reaction with acetate.The reaction is interpreted to take place by the redox and free-radical chain mechanism involving bromine atoms (ρ = -1.38 vs. ? + for substituted toluenes).In competiti ve experiments, benzyl and 4-nitrobenzyl acetates were found lees reactive than the corresponding toluenes in acetic acid with the couple S2O82-/Br- but more reactive in carbon tetrachloride with N-bromosuccinimide.
A novel stereoselective one-pot conversion of alcohols into alkyl halides mediated by N,N′-diisopropylcarbodiimide
Crosignani, Stefano,Nadal, Brice,Li, Zhengning,Linclau, Bruno
, p. 260 - 261 (2003)
Alcohols can be converted in high yields to the corresponding alkyl halides in a one-pot procedure via the corresponding O-alkylisourea; very short reaction times are possible when microwave irradiation is used.
Temperature Effects on Rates of Dehalogenation of Aromatic Anion Radicals
Meot-Ner (Mautner), M.,Neta, P.,Norris, Robert K.,Wilson, Karen
, p. 168 - 173 (1986)
The temperature dependence of the unimolecular dehalogenation of radical anions of nitrobenzyl halides and haloacetophenones was measured between -7 and 70 deg C.Activation parameters range from Ea=11.2-16.9 kcal/mol and log A=12.7-17.1.Both Ea and log A increase from p- to o-nitro radicals and from chloro to bromo radicals.Unfavorable steric effects that move the halogen atom out of the aromatic plane result in lowered A factors.In general, the variation of k294 with structure depends in a complex way on the combination of Ea and log A factors, which suggests caution in the evaluation of rate constants at one temperature.The fast unimolecular dissociation of (p-NO2C6H4CH2Br)(1-). (k294=4.6*105 s-1) allows measurement of the slower bimolecular electron transfer (C6H5NO2)(1-).+p-NO2C6H4CH2Br->(p-NO2C6H4CH2Br)(1-).+C6H5NO2 (k294=1.9*106 M-1 s-1).Both the activation energy and probability factor contribute to the slow rate, possibly due to a geometry change upon the reduction of ArNO2.Extending the temperature studies to supercooled solutions shows no discontinuity of the unimolecular rate constants near the phase transition temperatures.
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Baker,Nathan
, p. 236,237 (1936)
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NaIO4-mediated C-H activation of alkylbenzenes and alkanes with LiBr
Shaikh, Tanveer M.,Sudalai, Arumugam
, p. 5589 - 5592 (2005)
NaIO4 oxidizes lithium bromide efficiently under acidic conditions to functionalize alkylbenzenes and alkanes and produce the corresponding bromo and acetoxy derivatives in excellent yields. The protocol also demonstrates the direct conversion of cyclohexane into trans-1,2- dibromocyclohexane in moderate yield.
Thiourea-Catalyzed C?F Bond Activation: Amination of Benzylic Fluorides
Houle, Camille,Savoie, Paul R.,Davies, Clotilde,Jardel, Damien,Champagne, Pier Alexandre,Bibal, Brigitte,Paquin, Jean-Fran?ois
, p. 10620 - 10625 (2020)
We describe the first thiourea-catalyzed C?F bond activation. The use of a thiourea catalyst and Ti(OiPr)4 as a fluoride scavenger allows the amination of benzylic fluorides to proceed in moderate to excellent yields. Preliminary results with S- and O-based nucleophiles are also presented. DFT calculations reveal the importance of hydrogen bonds between the catalyst and the fluorine atom of the substrate to lower the activation energy during the transition state.
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Bernstein,Roth,Miller
, p. 2310,2313 (1948)
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Synthesis and bioactivity of novel triazole incorporated benzothiazinone derivatives as antitubercular and antioxidant agent
Shaikh, Mubarak H.,Subhedar, Dnyaneshwar D.,Arkile, Manisha,Khedkar, Vijay M.,Jadhav, Nandadeep,Sarkar, Dhiman,Shingate, Bapurao B.
, p. 561 - 569 (2016)
In search of new active molecules against Mycobacterium tuberculosis (MTB) H37Ra and M. bovis BCG, a small focused library of benzothiazinone based 1,2,3-triazoles has been efficiently prepared via click chemistry approach. Several derivatives were found to be promising inhibitors of MTB and M. bovis BCG characterized by lower MIC values (27.34-29.37 μg/mL). Among all the synthesized compounds, 6c and 6e is the most active compound against MTB and M. bovis BCG. The compounds were further tested for anti-proliferative activity against HeLa, A549 and A431 cell lines using MTT assay and showed no significant cytotoxic activity at the maximum concentration evaluated. Further, the synthesized compounds were found to have potential antioxidant activity with IC50 range = 14.14-47.11 μg/mL. Furthermore, to rationalize the observed biological activity data, the molecular docking study also been carried out against a potential target MTB DprE1, which revealed a significant correlation between the binding score and biological activity for these compounds. The results of the in vitro and in silico study suggest that the triazole incorporated benzothiazinone may possess the ideal structural requirements for further development of novel therapeutic agents.
Catalyst and solvent-free bromination of toluene derivatives by HBr-H 2O2 with visible-light photocatalysis using a continuous-flow micro reactor
Yu, Wu-Bin,Yu, Dong-Ping,Zheng, Ming-Ming,Shan, Shu-Ting,Li, Yu-Jin,Gao, Jian-Rong
, p. 258 - 260 (2012)
The efficiency of the bromination of toluene derivatives has been improved significantly by utilising a combination of hydrogen peroxide (30%) and hydrogen bromide (40%) in a continuous-flow micro reactor. This catalyst and solvent-free reaction takes place by visible-light photocatalysis.
Bromine/Bentonite Earth System, Promoter of Phenylmethanes from Toluene
Salmon, Manuel,Angeles, Enrique,Miranda, Rene
, p. 1188 - 1190 (1990)
The condensation of toluene to produce o- and p-methylphenylmethanes by use of bromine with a bentonitic earth catalyst has been investigated and a mechanism is proposed based on the isolated intermediates and other related reactions.
An efficient synthesis of benzyl bromides from aromatic aldehydes using polymethylhydrosiloxane and (bromodimethyl)sulfonium bromide or N-bromosuccinimide
Das, Biswanath,Srinivas, Yallamalla,Holla, Harish,Laxminarayana, Keetha,Narender, Ravirala
, p. 6681 - 6683 (2007)
Polymethylhydrosiloxane (PMHS) in combination with (bromodimethyl)sulfonium bromide or NBS has been utilized for the first time for reductive bromination of aromatic aldehydes at room temperature to afford the corresponding benzyl bromides in excellent yields.
The polyhedral nature of selenium-catalysed reactions: Se(iv) species instead of Se(vi) species make the difference in the on water selenium-mediated oxidation of arylamines
Capperucci, Antonella,Dalia, Camilla,Tanini, Damiano
supporting information, p. 5680 - 5686 (2021/08/16)
Selenium-catalysed oxidations are highly sought after in organic synthesis and biology. Herein, we report our studies on the on water selenium mediated oxidation of anilines. In the presence of diphenyl diselenide or benzeneseleninic acid, anilines react with hydrogen peroxide, providing direct and selective access to nitroarenes. On the other hand, the use of selenium dioxide or sodium selenite leads to azoxyarenes. Careful mechanistic analysis and 77Se NMR studies revealed that only Se(iv) species, such as benzeneperoxyseleninic acid, are the active oxidants involved in the catalytic cycle operating in water and leading to nitroarenes. While other selenium-catalysed oxidations occurring in organic solvents have been recently demonstrated to proceed through Se(vi) key intermediates, the on water oxidation of anilines to nitroarenes does not. These findings shed new light on the multifaceted nature of organoselenium-catalysed transformations and open new directions to exploit selenium-based catalysis.
Targeted Delivery of Persulfides to the Gut: Effects on the Microbiome
Dillon, Kearsley M.,Morrison, Holly A.,Powell, Chadwick R.,Carrazzone, Ryan J.,Ringel-Scaia, Veronica M.,Winckler, Ethan W.,Council-Troche, R. McAlister,Allen, Irving C.,Matson, John B.
supporting information, p. 6061 - 6067 (2021/02/01)
Persulfides (R?SSH) have been hypothesized as potent redox modulators and signaling compounds. Reported herein is the synthesis, characterization, and in vivo evaluation of a persulfide donor that releases N-acetyl cysteine persulfide (NAC-SSH) in response to the prokaryote-specific enzyme nitroreductase. The donor, termed NDP-NAC, decomposed in response to E. coli nitroreductase, resulting in release of NAC-SSH. NDP-NAC elicited gastroprotective effects in mice that were not observed in animals treated with control compounds incapable of persulfide release or in animals treated with Na2S. NDP-NAC induced these effects by the upregulation of beneficial small- and medium-chain fatty acids and through increasing growth of Turicibacter sanguinis, a beneficial gut bacterium. It also decreased the populations of Synergistales bacteria, opportunistic pathogens implicated in gastrointestinal infections. This study reveals the possibility of maintaining gut health or treating microbiome-related diseases by the targeted delivery of reactive sulfur species.