The Beckmann Rearrangement.

Blatt, A. H.

doi:10.1021/cr60042a002

Cited by 124 publications

(64 citation statements)

References 45 publications

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“…All reactions proceeded with excellent regioselectivities and migration to the secondary carbon atom, typical for Beckmann rearrangements. [12] Furthermore, we obtained exclusively one diastereomer with retention of the configuration at C-2, which is supported by observation of the expected J 1,2 and J 2,3 coupling constants for these products. Additionally, we obtained an X-ray structure of the lactam gluco-4 a (Supporting Information).…”

supporting

confidence: 74%

“…Interestingly, although the Beckmann rearrangement was discovered more than 100 years ago, [12] only few examples for the ring-expansion of furanosides or pyranosides have been described; [13] applications to modifying the side-chains of carbohydrates are hitherto unknown. On the other hand, cyclobutanones are easily available through the [2+2] cycloaddition of ketenes to double bonds.…”

mentioning

confidence: 99%

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Simple Synthesis of Conformationally Fixed Glycosamine Analogues by Beckmann Rearrangement at the Carbohydrate Ring

Umbreen

Linker

2015

Chemistry A European J

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Conformationally fixed carbohydrate analogues are promising small-molecule inhibitors for hydrolases like O-GlcNAcase (OGA); however, their synthesis usually requires many steps. Herein we describe cycloadditions of dichloroketene to various glycals and subsequent Beckmann rearrangements, which offer an easy and stereoselective entry to glycosamine derivatives in good yields. The reactions are applicable for hexoses, pentoses, and disaccharides, and transformations to the corresponding imidates proceed smoothly. First biological tests reveal that such imidates indeed inhibit human OGA.

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supporting

confidence: 74%

mentioning

confidence: 99%

Simple Synthesis of Conformationally Fixed Glycosamine Analogues by Beckmann Rearrangement at the Carbohydrate Ring

Umbreen

Linker

2015

Chemistry A European J

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“…The Beckmann rearrangement [1][2][3][4][5][6] reaction for the production of the e-caprolactam is one of the most important industrial reactions. This rearrangement reaction yields the raw material for producing the Nylon-6 polymer, which had a market consumption of a million tons in 1998.…”

Section: Introductionmentioning

confidence: 99%

Vapor‐Phase Beckmann Rearrangement of Oxime Molecules over H‐Faujasite Zeolite

Sirijaraensre

Limtrakul

2006

ChemPhysChem

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The Beckmann rearrangement (BR) plays an important role in a variety of industries. The mechanism of this reaction rearrangement of oximes with different molecular sizes, specifically, the oximes of formaldehyde (H(2)C=NOH), Z-acetaldehyde (CH(3)HC=NOH), E-acetaldehyde (CH(3)HC=NOH) and acetone (CH(3))(2)C=NOH, catalyzed by the Faujasite zeolite is investigated by both the quantum cluster and embedded cluster approaches at the B3LYP level of theory using the 6-31G (d,p) basis set. To enhance the energetic properties, single point calculations are undertaken at MP2/6-311G(d,p). The rearrangement step, using the bare cluster model, is the rate determining step of the entire reaction of these oxime molecules of which the energy barrier is between 50-70 kcal mol(-1). The more accurate embedded cluster model, in which the effect of the zeolitic framework is included, yields as the rate determining step, the formaldehyde oxime reaction rearrangement with an energy barrier of 50.4 kcal mol(-1). With the inclusion of the methyl substitution at the carbon-end of formaldehyde oxime, the rate determining step of the reaction becomes the 1,2 H-shift step for Z-acetaldehyde oxime (30.5 kcal mol(-1)) and acetone oxime (31.2 kcal mol(-1)), while, in the E-acetaldehyde oxime, the rate determining step is either the 1,2 H-shift (26.2 kcal mol(-1)) or the rearrangement step (26.6 kcal mol(-1)). These results signify the important role that the effect of the zeolite framework plays in lowering the activation energy by stabilizing all of the ionic species in the process. It should, however, be noted that the sizeable turnover of a reaction catalyzed by the Brønsted acid site might be delayed by the quantitatively high desorption energy of the product and readsorption of the reactant at the active center.

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“…A relevância do grupo oxima na Síntese Orgânica está relacionada com a versatilidade desta classe de compostos, visto que as oximas podem ser obtidas a partir de uma série de grupos funcionais, tais como: aldeídos, 33 cetonas, 33 olefinas, 34 aminas, 35 nitrocompostos, 36 nitritos 37 e compostos que apresentam hidrogênios carbonila. 24 Grupos nitrogenados, como: amidas, 39 anéis isoxazolínicos, 40 nitrosos, 41 nitrocompostos, 42 nitrilas 43 e aminas 44 podem ser preparados a partir de oximas, Esquema 4.…”

Section: Métodos De Preparação De Oximasunclassified

Oximes: Chemical Properties, Methods of Preparation and Applications in Synthesis of Nitrogen Functional Groups

Araújo

Gonsalves

2015

Revista Virtual De Química

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Oxime is an organic functional group having the following general formula RR'C=N-OH and although its unquestionable importance in the Coordination Chemistry and Organic Synthesis it is a subject underexplored by main chemistry textbooks in higher education adopted in Brazil. Thus, this article is a review about oximes organized in three parts. First are shown the properties of the oximes with emphasis in its isomerism and behavior in solution. After, are discussed some methods for obtaining oximes, such as oximation of carbonyl groups and double bonds, oxidation of amines, reduction of nitro compounds and the radical. Finally, in the third part of the article are treated some synthetic routes of nitrogen functional groups where oximes are precursors. ResumoOxima é u g upo fu io al o g i o ue ap ese ta a fó ula ge al RR'C=N-OH e apesar da sua relevância inquestionável na Química das Coordenações e na Síntese Orgânica este é um tema pouco explorado pelos principais livros de Química de ensino superior adotados no Brasil. Desta forma, o presente artigo trata de uma revisão sobre oximas, que está organizado em três partes. Inicialmente são mostradas as propriedades das oximas dando ênfase a sua isomeria e comportamento em solução. Em seguida, são abordadas algumas metodologias para a obtenção de oximas, como: oximação de carbonilas e duplas ligações, oxidação de aminas, redução de nitrocompostos e por via radicalar. Por fim, na terceira parte do artigo são tratadas algumas vias de síntese de grupos funcionais nitrogenados onde oximas são precursoras. Palavras-chave:Oxima; Propriedades Químicas das Oximas;

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The Beckmann Rearrangement.

Cited by 124 publications

References 45 publications

Simple Synthesis of Conformationally Fixed Glycosamine Analogues by Beckmann Rearrangement at the Carbohydrate Ring

Simple Synthesis of Conformationally Fixed Glycosamine Analogues by Beckmann Rearrangement at the Carbohydrate Ring

Vapor‐Phase Beckmann Rearrangement of Oxime Molecules over H‐Faujasite Zeolite

Oximes: Chemical Properties, Methods of Preparation and Applications in Synthesis of Nitrogen Functional Groups

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