Sugar dialdehydes

A mixture of methyl 3-deoxy-3-C-methyl-3-nitro-a-D- and P-L-glucopyranosides (1 1) is formed by the reaction of nitroethane with the sugar dialdehyde obtained from D-glucose. The products are separated and converted into branched-chain fluoro nitro d- and L-sugars (Eq 3.61).99... 

An unusual observation was made on nitroethane cyclization of the dialdehydes (37 a) and (37 b), obtainable from a- and p-methyl D-gluco-pyranoside (36), respectively, by periodate oxidation. In distinct contrast to the course of the nitromethane cycUzations of these and a range of other sugar dialdehydes D, the products that result, i.e. (43), have undergone epimerization at C-5 as compared to (39). thus raising the number of isomers to be expected to 16. 

Scheme 4. Richardson s application of the Fischer nitromethane cyclization to the sugar dialdehyde derived from the periodate cleavage of levoglucosan (1960).

Glycosides of 3-deoxy-3-nitroaldoses are readily available by the cyclization of sugar dialdehydes with nitromethane. Introduced in 1958 by Baer and Fischer,48 the method has been widely employed, and some aspects have been reviewed.49,50 The term sugar dialdehydes refers to products of glycol cleavage of glycosides.51 The formation, structure, conformation, and reaction of such dialdehydes have been discussed in detail in previous Chapters of these Volumes.52-54 The compounds exist in aqueous and alcoholic solutions as solvated, cyclic forms that are internal hemialdals or hemiacetals.54 However, under the conditions of the nitromethane cyclization, mobile equilibria are rapidly shifted from such cyclic products toward carbonyl species, and it is, therefore, permissible and customary in... 

In view of the great facility with which base-catalyzed alkoxylations of nitro-olefinic sugars tend to occur, it might be suspected that side reactions involving the formation of methylated derivatives might accompany nitromethane cyclizations of sugar dialdehydes in methanolic medium. There is as yet no evidence for this, but special... 

Hexoses - The synthesis of hexoseptanose derivatives by ring expansion of uloses, Baeyer Villiger oxidation of inositols, or Baeyer-Fischer reaction of sugar dialdehydes has been reviewed. ... 

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