CXCIII.—The bromination of phenol. 2 : 4- and 2 : 6-dibromophenol

Pope, Frank George; Wood, Arthur Samuel

doi:10.1039/ct9120101823

Cited by 13 publications

(5 citation statements)

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“…1 -Benzyl-1,4-dihydronicotinamide (mp 123°; Mauzerall and Westheimer, 1955), 3,5-dichloro-4-hydroxybenzoic acid (mp 263°; Gray and Jones, 1954), and 3,5-dibromo-4-hydroxybenzoic acid (mp 278°; Pope and Wood, 1912) were prepared according to the literature. o-Bromophenol, o-iodophenol, 2,6-dibromophenol, 4-hydroxybenzoic acid and its 3,5-diiodo derivative, DL-tyrosine, and cysteine hydrochloride were all from Eastman Organic Chemicals; L-3-iodotyrosine, L-3,5-dibromotyrosine, and L-3,5-diiodotyrosine were from Aldrich Chemical Co.…”

Section: Methodsmentioning

confidence: 99%

Pyridine coenzymes. VII. Catalysis of the hydration of the reduced form by iodoaromatic compounds

Schreier¹,

Cilento²

1969

Biochemistry

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Section: Methodsmentioning

confidence: 99%

Pyridine coenzymes. VII. Catalysis of the hydration of the reduced form by iodoaromatic compounds

Schreier¹,

Cilento²

1969

Biochemistry

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“…They subjected 4-hydroxybenzoic acid in cold sulfuric acid to bromine in an attempt to synthesize 2,6-dibromophenol, but the major isolated product from the reaction was 2,4,6-tribromophenol. 20 Later, Krishna and Pope 21 during their analysis of salicylic acid by the iodometric determination of acids observed significantly lower amounts of liberated iodine than expected from reaction 1 : Evolution of carbon dioxide and iodine was observed during the reaction. However, the iodine color vanished with time, accompanied by the formation of a precipitate, which was identified as 2,4,6-triiodophenol.…”

Section: Pioneering and Classical Methodsmentioning

confidence: 97%

“…Since then, a very few sporadic examples were reported, mentioning the introduction of the halogen function, via a decarboxylation in the very specific substrates. − These included a first halodecarboxylation of aromatic acids , which was observed by Pope and Wood upon halogenation of hydroxybenzoic acids. They subjected 4-hydroxybenzoic acid in cold sulfuric acid to bromine in an attempt to synthesize 2,6-dibromophenol, but the major isolated product from the reaction was 2,4,6-tribromophenol . Later, Krishna and Pope during their analysis of salicylic acid by the iodometric determination of acids observed significantly lower amounts of liberated iodine than expected from reaction : Evolution of carbon dioxide and iodine was observed during the reaction.…”

Section: Pioneering and Classical Methodsmentioning

confidence: 99%

Decarboxylative Halogenation of Organic Compounds

2020

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Decarboxylative halogenation, or halodecarboxylation, represents one of the fundamental key methods for the synthesis of ubiquitous organic halides. The method is based on conversion of carboxylic acids to the corresponding organic halides via selective cleavage of a carbon–carbon bond between the skeleton of the molecule and the carboxylic group and the liberation of carbon dioxide. In this review, we discuss and analyze major approaches for the conversion of alkanoic, alkenoic, acetylenic, and (hetero)aromatic acids to the corresponding alkyl, alkenyl, alkynyl, and (hetero)aryl halides. These methods include the preparation of families of valuable organic iodides, bromides, chlorides, and fluorides. The historic and modern methods for halodecarboxylation reactions are broadly discussed, including analysis of their advantages and drawbacks. We critically address the features, reaction selectivity, substrate scopes, and limitations of the approaches. In the available cases, mechanistic details of the reactions are presented, and the generality and uniqueness of the different mechanistic pathways are highlighted. The challenges, opportunities, and future directions in the field of decarboxylative halogenation are provided.

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“…Também, podem ser formados durante o processo de tratamento de águas residuais submetidas à cloração, devido à presença do ion brometo. O que diferencia os dois processos é a origem dos compostos fenólicos e o mecanismo de formação do HBrO, responsá-vel pela bromação, através de reações de substituição eletrofílica 29,55,56 . No caso da marinação, os compostos fenólicos podem ser provenientes de impurezas contidas no vinagre, enquanto que águas e sedimentos podem ser originários da degradação de compostos fenólicos complexos de organismos vivos 29 .…”

Section: Formaçãounclassified

Bromofenóis simples relacionados ao "flavor" de organismos marinhos

Silva¹,

Lopes²,

Andrade³

et al. 2007

Quím. Nova

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Recebido em 18/1/06; aceito em 4/8/06; publicado na web em 19/1/07 BROMINATED PHENOLS AS KEY FLAVOR COMPOUNDS FOUND IN MARINE ORGANISMS. The perception of the flavor is an important attribute of quality in marine fish and other seafoods, being the first and main factor of discrimination for the evaluation, later acceptance and preference of the product by the consumer. Recently, the simple bromophenols have been considered an important group of key flavor compounds occurring in a wide variety of seafood species like fishes, mollusks, crustaceans and algae. When present in high concentration, in seafood, the bromophenols produce an undesirable flavor and are associated with inferior quality. Meanwhile, when present in low concentration levels (for example ng g -1 ) these compounds produce a desirable marine -or ocean-like -flavor and enhance the existing flavor in seafood. Indeed, simple bromophenols are widespread in seafood but virtually absent in freshwater fish. Herein we present a review on these flavor components found in the marine environment.Keywords: bromophenol; flavor; marine organisms. INTRODUÇÃOA qualidade dos alimentos de origem marinha é determinada por uma variedade de fatores pré e pós-pesca, incluindo dieta, condições ambientais, processamento, estocagem, transporte e pode estar associada à presença de substâncias químicas. Dependendo da concentração, estas substâncias podem contribuir para melhorar ou piorar a qualidade desses alimentos, pois interferem diretamente em suas características sensoriais, tornado o "flavor" mais agradável ("on-flavor") ou desagradável ("off-flavor") [1][2][3][4] .Segundo a Associação Brasileira de Normas Técnicas (ABNT) 5 o termo "flavor" significa sabor. No entanto, de acordo com a literatura internacional, "flavor" se emprega no sentido mais amplo ou da percepção global integrada de todos os sentidos, no momento da degustação e ingestão de um alimento. A esta percepção sensorial, são somadas sensações subjetivas que estão associadas aos hábitos, aos padrões culturais e à sensibilidade de cada indivíduo (Figura 1). Assim, a análise do "flavor" deve considerar também as sensações auditivas, visuais e táteis, além das gusto-olfativas 6,7 .Dentre as substâncias que podem atuar e interferir na qualidade dos alimentos de origem marinha destacam-se os bromofenóis simples, exemplificados pelo 2 e 4-bromofenol (2-BF, 4-BF), 2,4 e 2,6-dibromofenol (2,4-DBF, 2,6-DBF) e 2,4,6-tribromofenol (2,4,6-TBF) 3 , os quais podem produzir, intensificar ou alterar o "flavor" desses alimentos. Estes bromofenóis têm sido encontrados em concentrações na ordem de ng g -1 em peixes marinhos, moluscos, crustáceos, sendo fortemente associados ao "flavor" agradável (marinado) ou desagradável (iodofórmico), em função de suas concentrações 3,[8][9][10][11][12] .A maioria dos estudos sobre o "flavor" de alimentos de origem marinha tem sido direcionada para peixes. O primeiro relato sobre "off-flavor" em peixes data de 1558, quando Conrad Gesner observou que o músculo do peixe Tinca tinca poderia ...

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CXCIII.—The bromination of phenol. 2 : 4- and 2 : 6-dibromophenol

Cited by 13 publications

References 0 publications

Pyridine coenzymes. VII. Catalysis of the hydration of the reduced form by iodoaromatic compounds

Pyridine coenzymes. VII. Catalysis of the hydration of the reduced form by iodoaromatic compounds

Decarboxylative Halogenation of Organic Compounds

Bromofenóis simples relacionados ao "flavor" de organismos marinhos

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