Increasing the Selectivity of Bromination of Aromatic Compounds Using Br2/SiO2

Ghiaci, Mehran; Asghari, Jila

doi:10.1246/bcsj.74.1151

Cited by 29 publications

(7 citation statements)

References 7 publications

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“…2,2-Dibromo-1-arylethanones are used in organic synthesis primarily for the construction of heterocyclic structures [1][2][3] and small rings, [4][5][6] for the preparation of compounds with a double [7][8][9] or triple 10 bond, and in reactions with phosphorous esters 11,12 and thiols. 13,14 Most of the known methods for the synthesis of 2,2-dibromo-1arylethanones are based on bromination of acetophenones with molecular bromine 8,11,[15][16][17][18] and its complex compounds. 19,20 In the last two decades, chlorination and bromination of organic compounds with HCl or HBr combined with peroxides have developed extensively.…”

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confidence: 99%

A Convenient Synthesis of 2,2-Dibromo-1-arylethanones by Bromination of 1-Arylethanones with the H₂O₂-HBr System

Terent’ev¹,

Khodykin²,

Krylov³

et al. 2006

Synthesis

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S y n t h e s i s o f 2 , 2 -D i b r o m o -1 -a r y l e t h a n o n e s Alexander O. Terent'ev,* Abstract: 1-Arylethanones and related compounds are brominated in dioxane with the H 2 O 2 -HBr aq system, resulting in the replacement of two hydrogen atoms in the methyl group with bromine. The reaction is also accompanied by bromination of the aromatic ring provided that the latter contains electron-donating substituents. The reaction proceeds rapidly (20 min) and results in complete conversion of ketones to give 2,2-dibromo-1-arylethanones in yields up to 86%.2,2-Dibromo-1-arylethanones are used in organic synthesis primarily for the construction of heterocyclic structures 1-3 and small rings, 4-6 for the preparation of compounds with a double 7-9 or triple 10 bond, and in reactions with phosphorous esters 11,12 and thiols. 13,14 Most of the known methods for the synthesis of 2,2-dibromo-1-arylethanones are based on bromination of acetophenones with molecular bromine 8,11,15-18 and its complex compounds. 19,20 In the last two decades, chlorination and bromination of organic compounds with HCl or HBr combined with peroxides have developed extensively. 21-38 These methods are most actively used for halogenation of arenes, 22-26,28-36 alkenes, 21,23 and ketones. 37,38 As part of our continuing studies on the use of hydrogen peroxide in organic synthesis, in particular the halogenation of ketones, 38 we report the results of bromination of 1-arylethanones with the H 2 O 2 -HBr system. The influence of experimental conditions on the selectivity of bromination and the yield of 2,2-dibromo-1-phenylethanone was revealed using acetophenone (1) as an example (Scheme 1, Table 1). The reaction was carried out by adding 35% aqueous hydrogen peroxide to a refluxing solution of ketone 1 in dioxane (acetic acid) and 48% hydrobromic acid for one minute. Then the mixture was refluxed with stirring for 20 minutes. The reaction afforded dibromoketone 3 as the major product and mono-(2) and tribromoketones (4) as by-products.Our study demonstrated that the highest yield (84%) of dibromoketone 3 was achieved in the presence of a fourfold molar excess of H 2 O 2 (run 1). In the presence of a threefold molar excess of H 2 O 2 (run 2), the yield of 3 decreased to 78%, and monobromoketone 2 remained unconsumed. A decrease in the amount of HBr (run 3), a decrease in the reaction time to 8 min (run 4), or lowering of the reaction temperature to 50 °C (run 5) also lead to a decrease in the yield of dibromoketone 3.Bromination of ketone 1 in acetic acid in the presence of sulfuric acid afforded dibromoketone 3 in 43% yield and tribromoketone 4 in 48% yield. The formation of product 4 is the first example of the preparation of 2,2,2-tribromo-1-phenylethanone in an acidic medium in a satisfactory yield. The use of a larger amount of H 2 O 2 did not lead to a considerable increase in the conversion of acetophenone 1 to tribromoketone 4. Alternative procedures for the synthesis of tribromoketone 4 are based on bromination of acetophenone in ac...

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confidence: 99%

A Convenient Synthesis of 2,2-Dibromo-1-arylethanones by Bromination of 1-Arylethanones with the H₂O₂-HBr System

Terent’ev¹,

Khodykin²,

Krylov³

et al. 2006

Synthesis

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“…The most conventional brominating agent remains topically Br 2 , although it is hazardous and difficult in handling together with poor atom efficiency. A large panel of brominating reagents have been thus developed, including molecular bromine with or without catalysts [6][7][8][9], N-bromosuccinimide (NBS) [10-13], 1,3-dibromodimethylhydantoin (DBDMH) [13,14], N,N-dibromo-p-toluenesulfonamide (TsNBr 2 ) [15], KBrO 3 [16], or quaternary ammonium tribromide [17][18][19], etc. All of the aforementioned reagents are used in stoichiometry amount, more or less efficient, expensive, toxic, not commercially available and lead to large amounts of wastes at the end of the reaction.…”

Section: Introductionmentioning

confidence: 99%

Sono-bromination of aromatic compounds based on the ultrasonic advanced oxidation processes

Fujita

Lévêque

Komatsu

et al. 2015

Ultrasonics Sonochemistry

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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.

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“…Molecular bromine is generally used in nuclear bromination, which generates toxic and corrosive HBr as a side product. Unused (excess) molecular bromine and the liberated HBr cause hazardous and harmful environment when sent to the drain [7][8][9]. How-Correspondence to: K. C. Rajanna; e-mail: kcrajannaou@ yahoo.com.…”

Section: Introductionmentioning

confidence: 99%

“…Molecular bromine is generally used in nuclear bromination, which generates toxic and corrosive HBr as a side product. Unused (excess) molecular bromine and the liberated HBr cause hazardous and harmful environment when sent to the drain . However, the need for bromo aromatic compounds has led the chemists to develop alternative environmentally safe and ecofriendly bromination protocols .…”

Section: Introductionmentioning

confidence: 99%

Bromination of Anisoles Using N‐Bromophthalimide: A Synthetic and Kinetic Approach

Anjaiah

Kumar

Srinivas

et al. 2015

Int J of Chemical Kinetics

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N‐Bromophthalimide (NBP)‐triggered bromination of aromatic compounds has been studied in the presence of aqueous acetic acid. Reaction Kinetics indicated first order in [NBP] and zero order in [Anisole]. The reactions afforded very good yields of corresponding bromo derivatives under kinetic conditions. The mechanism of the reaction is explained through the formation of acetyl hypobromite due to the interaction of NBP and acetic acid, which in turn reacts with anisole to afford a bromo derivative of anisole.

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Increasing the Selectivity of Bromination of Aromatic Compounds Using Br2/SiO2

Cited by 29 publications

References 7 publications

A Convenient Synthesis of 2,2-Dibromo-1-arylethanones by Bromination of 1-Arylethanones with the H₂O₂-HBr System

A Convenient Synthesis of 2,2-Dibromo-1-arylethanones by Bromination of 1-Arylethanones with the H₂O₂-HBr System

Sono-bromination of aromatic compounds based on the ultrasonic advanced oxidation processes

Bromination of Anisoles Using N‐Bromophthalimide: A Synthetic and Kinetic Approach

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Increasing the Selectivity of Bromination of Aromatic Compounds Using Br2/SiO2

Cited by 29 publications

References 7 publications

A Convenient Synthesis of 2,2-Dibromo-1-arylethanones by Bromination of 1-Arylethanones with the H2O2-HBr System

A Convenient Synthesis of 2,2-Dibromo-1-arylethanones by Bromination of 1-Arylethanones with the H2O2-HBr System

Sono-bromination of aromatic compounds based on the ultrasonic advanced oxidation processes

Bromination of Anisoles Using N‐Bromophthalimide: A Synthetic and Kinetic Approach

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Product

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A Convenient Synthesis of 2,2-Dibromo-1-arylethanones by Bromination of 1-Arylethanones with the H₂O₂-HBr System

A Convenient Synthesis of 2,2-Dibromo-1-arylethanones by Bromination of 1-Arylethanones with the H₂O₂-HBr System