Lobry de Bruyn-Alberda van Ekenstein reactions

Lobry de Bruyn-Alberda van Ekenstein reaction, 4 712 Lobsters, aquaculture, 3 189 Local chain conformation, HDPE, 20 162 Local emergency planning committee (LEPC), 21 589... 

Enzyme-catalyzed Lobry de Bruyn-Alberda van Ekenstein Reactions... 

Catalysis of Lobry de Bruyn-Alberda van Ekenstein reactions by a strongly basic, ion-exchange resin [Amberlite IRA-400(OH)] has now been demonstrated. Duff has reported that alkaline impurities present in paper brought about such transformations of several sugars when paper chromatograms thereof were dried at 110°. 

Nearly all of the investigations of the kinetics of Lobry de Bruyn-Alberda van Ekenstein reactions have failed because of the complications imposed by side-reactions. It has only recently been found that good kinetic data can be obtained for the DL-glycerose-l,3-dihydroxy-2-propanone interconversion. This Section mainly concerns the work with this simple system, which contains implications for the mechanisms of all Lobry de Bruyn-Alberda van Ekenstein reactions, and the attempts to extend it to the higher sugars. 

Angyal SJ (2001) The Lobry de Bruyn-Alberda van Ekenstein Transformation and Related Reactions. 215 1-14... 

Albrecht M (2004) Supramolecular Templating in the Formation of Helicates. 248 105-139 Ando T, Inomata S-I, Yamamoto M (2004) Lepidopteran Sex Pheromones. 239 51-96 Angyal SJ (2001) The Lobry de Bruyn-Alberda van Ekenstein Transformation and Related Reactions. 215 1-14... 

Aldoses generally undergo benzilic acid-type rearrangements to produce saccharinic acids, as well as reverse aldol (retro-aldol) reactions with j3-elimination, to afford a-dicarbonyl compounds. The products of these reactions are in considerable evidence at elevated temperatures. The conversions of ketoses and alduronic acids, however, are also of definite interest and will be emphasized as well. Furthermore, aldoses undergo anomerization and aldose-ketose isomerization (the Lobry de Bruyn-Alberda van Ekenstein transformation ) in aqueous base. However, both of these isomerizations are more appropriately studied at room temperature, and will be considered only in the context of other mechanisms. 

The reaction of carbohydrates in alkaline or acidic aqueous solutions results in a myriad of products, many of which have been recognized for well over a century. The number of identified products has greatly increased in recent years, owing to the development of sophisticated techniques for separation and identification. With the exception of anhydro sugars and oligosaccharides, found as concentration-dependent, equilibrium constituents (reversion products) in acidic solutions, all of the products result from reactions of intermediates present in the Lobry de Bruyn-Alberda van Ekenstein transformation. 

The products obtained by the reaction of sugars with aqueous ammonia for a short time at low temperature, in the absence of catalysts (see Table I) are simply those obtained by the action of alkali on the sugars. The reaction is known as the Lobry de Bruyn-Alberda van Ekenstein transformation87 after the chemists who dis-... 

The main reactions are 1,2-enolisation (Lobry de Bruyn-Alberda van Ekenstein rearrangement, cf. Amadori rearrangement), dehydration to furfurals, and fission (see ref. 563). 

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