Hexaacetyl 2-

The addition of bromine to the hexaacetyllactal leads to a mixture of dibromides, from which one that is apparently homogeneous could be isolated.47 Two chlorine atoms could also be added.48 The halogen in the 1-position can be replaced easily by the action of moist silver oxide or silver carbonate, and hexaacetyl-2-desoxy-2-halogeno-lactose (or epi-lactose) is formed. This compound can be converted with lead oxide to the 2-desoxylactobionic acid.49... 

According to an unsupported statement in connection with this work,176 2-desoxy-maltose was converted into hexaacetyl-2-desoxy-cellobiose. 

In the case of the oximes of the aldose sugars, the situation is more complicated because of the possibility of both open-chain and cyclic structures. That aldose oximes can react in the open-chain form follows from the formation of the nitriles and from the isolation of acylated open-chain aldose oximes as secondary products in preparation of nitriles. For example, Wolfrom and Thompson, by the action of sodium acetate-acetic anhydride on n-glucose oxime, not only obtained pentaacetyl-D-glucononitrile, in 40% yield, but also isolated a small amount of hexaacetyl-oWeAydo-D-glucose oxime (V) identical with that prepared by mild acetylation of pentaacetyl-aWe%do-D-glucose oxime (IV) whose structure was assured by its formation from pentaacetyl-aldehydo-D-glucoae (III). 

This hexaacetyl-aWe%do-D-glucose oxime was easily transformed into the nitrile by heating at 135-140 , or by treatment with sodium acetate-acetic anhydride, and Wolfrom and Thompson considered the open-chain oxime and its acetylated derivative to be an intermediate in the production of the nitrile. We have no proof of the original structure of the oxime. Under the conditions of temperature employed, even a syn oxime can be transformed into the nitrile. If we accept the assumption that the isolated open-chain oxime is the only intermediate, its... 

Wohl isolated a hexaacetyl-D-glucose oxime from the mother liquor obtained during the preparation of pentaacetyl-D-glucononitrile. The same acetylated oxime was prepared by Behrend. Wolfrom and Thompson studied it further, and showed conclusively that it possessed a ring structure XI, for it could not be transformed into a nitrile. Because of its low specific rotation, it was assigned to the jS-d series. 

A cyclic hexaacetyl oxime (XII) was also isolated by mild acetylation of D-galactose oxime and by treatment with sodium acetate and acetic anhydride. A cyclic aldoxime acetate (XIII) was also obtained by Voto6ek from D-fucose oxime, and by Restelli de Labriola and Deulofeu ... 

The diacetamide compounds were regularly obtained in all degradations employing ammonia with or without silver oxide until Hockett and Chandler applied the method to hexaacetyl-D-gluco-D-flruZo-heptono-nitrile (XLIX) and obtained a monoacetamide derivative that was identified as iV-acetyl-D-glucofuranosylamine (L). The furanose structure of L was established by lead tetraacetate oxidation. They... 

D-Manno- D-galsi-heptose. Hexaacetyl-D-manno-D-goZa-heptononitrile was prepared by Miksic and by Brigl, Miihlschlegel and Schinle by acetylation of the free nitrile. It was degraded with methanolic ammonia and silver nitrate, giving D-mannose diacetamide in 34% yield. 

Hydrogenation of L-sorbose, with Raney nickel catalyst to poly-hydric alcohols is the subject of a recent patent this type of reduction had previously been shown to give the expected L-iditolI 1 and D-glucitol. The open-chain acetate, keto-L-sorbose pentaacetate, on reduction192 at low pressure with platinum catalyst, gave on subsequent acetylation hexaacetyl-D-glucitol (XLIV) and hexaacetyl-L-iditol (XLV), while... 

Hydrogenation of hexaacetyllactal (LIV) gives hexaacetyl-dihydro-lactal, deacetylation of which yields dihydrolactal (LVI). This latter compound is prepared especially smoothly by hydrogenation of the free lactal (LV).47... 

Hexaacetylcellobial has been oxidized by ozone to hexaacetyl-3-(/S-D-glucopyranosyl)-D-arabinose 66 the free sugar can be prepared from this acetate. 

An acetyl group is easily removed as acetic acid from hexaacetyl-cellobial by boiling its aqueous solutions. Just as in the case of the other glycal acetates, it yields thereby the pentaacetylpseudocellobial (LXVIII).88 This compound can be acetylated to hexaacetylpseudo-... 

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