Of anhydro sugars

Structure and Reactivity of Anhydro-sugars. Part I. Branched-chain Sugars. Part I. Action of Di-ethylmagnesium on Methyl 2 3-Anhydro-4 6-0-benzylidene-a-D-mannoside, A. B. Foster, W. G. Overend, M. Stacey, and G. Vaughan,/. Chem. Soc., (1953) 3308-3313. 

VIII. Tables of Properties of Anhydro Sugars and Their Derivatives. 69... 

The two main classes of anhydro sugars are therefore the ethylene oxide and the hydrofuranol types. Other anhydro ring systems are known but the number of representatives of such systems is not great. 

This procedure provided the most important method for the synthesis of anhydro sugars of the hydrofuranol type. 3,6-Anhydro sugars have resulted from the saponification of hexoses esterified at C6 by the following cationogens Br- 3 36 14- 36 CH3 C H4 S020 37, 3S- 39> 40 HO-SCVO-41 42 02N-0-.43 It is very probable that the phosphate ion is also cationogenic and that saponification of a hexose 6-phosphate... 

This section presents selected examples of the use of zeolites and related porous materials for transformations of carbohydrates, that fall beyond the scope of the previous paragraphs. They include the use of zeolites in click chemistry and in a variety of reactions, including the synthesis of anhydro sugars, cyclization, elimination, and addition reactions to the carbonyl group. 

Reference has already been made to the formation of anhydro sugars under the influence of acid (see Section XI, p. 87). In a similar manner, alditols may be converted into anhydroalditols, and these may be difficult to distinguish from other polyhydric compounds of low molecular weight. Such a problem arises in the hydrolyzates of cell walls, where ribitol and glycerol are present. It has been shown, however, by Gregory that glycerol and an anhydroribitol may be separated readily as their trimethylsilyl ethers.401... 

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 two best-known syntheses of anhydro sugars are clearly those of 1,6-anhydro-/3-D-glucopyranose by alkaline treatment of phenyl... 

---