Sugars oxirane sugar derivatives from

Oxiranes derived from sugars enter this category. Note that 4.36, methyl 2,3-anhydro-4,6-O-benzylidene-a-D-allopyranoside, is named as an alio derivative. 

Oxirans derived from branched-chain sugars are mentioned in Chapter 4, while the m.s. of some 2,6-dideoxy-3-C-methylhexopyranose derivatives is referred to in Chapter 24. 

The racemic form of methyl 3,4-anhydro-/3-mycaroside (82) has been synthesized 35 it is an epoxide of a branched-chain sugar having the oxirane ring fused to the pyranose ring. Hydrolysis of the oxirane ring with hydrochloric acid in aqueous p-dioxane occurs with substitution at C-4, the (more accessible) secondary position, as would be expected from its favored °H, conformation (82) anticipated, because it is an analog of the 3,4-anhydro-D-allopyranoside derivatives considered previously (see p. 148). 

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. 

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