Anhydrides, sugar

In this review, therefore, the following classes of sugar anhydrides will be considered ... 

Such sugar anhydrides and their derivatives as have been described in the literature to the year 1944 are included in Tables II, III, IV, V and VI and are classified under the above groups. 

Internal-displacement reactions to give sugar anhydrides are well known, and anhydro derivatives of sucrose have been prepared by treatment of the respective sulfonates or chlorides with a base. Buchanan and coworkers described the synthesis of 3, 6 -anhydrosucrose by treating 2,3,4,6,l, 3, 4 -hepta-0-acetyI-6 -0-(p-ni-trophenylsulfonyl)sucrose with sodium ethoxide in ethanol for 2 h under reflux.18 Similar treatment of 2,3,4,l, 3, 4, 6 -hepta-0-acetyl-6-chloro-6-deoxysucrose (46) with sodium methoxide in methanol, followed by acetylation, gave crystalline 2,4,l, 3, 4, 6 -hexa-0-acetyl-3,6-anhydrosucrose (47) in 83% yield.81 The H n.m.r. spectrum of 47... 

Sumitomo, H. and M. Okada, Sugar Anhydrides and Related Bicyclic Acetals, Chap. 5 in Ring-Opening Polymerization, Vol. 1, K. J. Ivin and T. Saegusa, eds., Elsevier, London, 1984. 

Fructosans are a group of sugar anhydrides which hydrolyze to fructose. One of its derivatives, Fmctosan Trinitrate, is prepd from fructose... 

Mathews and Jackson did not carry out fermentation experiments nor did they discuss the possible relation between D-fructose anhydrides and the glutose of Lobry de Bruyn and Alberda van Ekenstein. They merely concluded that the well-known reversion products in cane molasses probably consist of these same anhydrides. The term reversion product was first introduced by WohP to describe the sugar anhydrides formed when highly concentrated D-fructose or invert sugar solutions are heated in the presence of acid. He anticipated Mathews and Jackson s... 

In this volume of Advances, Cerny and Stanek, Jr. (Prague) contribute a comprehensive article on the 1,6-anhydro derivatives of aldohexoses. This class of anhydro sugars, earlier termed the hexosans, constitutes by far the largest class of sugar anhydrides to have been studied. The scope of the topic is now so extensive that the Editors, in view of their earlier practice of limiting chapter size in individual volumes of Advances in the interest of diversification of subject material, were inclined to divide this chapter into two parts, to appear in successive volumes. However, as the latter practice has elicited some unfavorable reaction from readers on previous occasions, it was decided to present the article here in its entirety. The chapter complements previous ones on other classes of anhydro derivatives, in particular, recent ones on anhydrides of the oxirane (epoxide) and 2,5-anhydro (oxolane) types. 

Even if the water is rapidly removed by vacuum, at this stage the reactions will inevitably tend to follow the course of those occurring in very concentrated solution. The sugar anhydrides readily form dimers, levulosan in particular being converted into diheterolevulosans. It is now known that similar products are formed by refluxing fructose in 80% solution (24). The reactions of caramelization cannot be limited to the initial stages without simultaneous further dehydration and polymerization, as well as extensive degradation to produce hydroxymethylfurfural (13). 

The dioxaspiro [5,5j undecane (45), a building block for the anti-parasitic agents milbemycin and avermectin, has been constructed in enantiomerically pure form from the dideoxy-sugar anhydride (46), which yields the phosphonium salt (47) on treatment with triphenyl-phosphonium tetrafluoroborate the ylide derived from (47) was... 

Sugar anhydrides internal acetals formed by intramolecular removal of water from a sugar molecule. They are chemically similar to glycosides and can be hydrolysed to the corresponding sugars by water or (Uute acids. 

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