Cellobiose heptaacetate

A remarkable inertness towards acylation is shown by the secondary hydroxyl group on C-3 in maltose, lactose, and their methyl j8-glycosides. Benzoylation of maltose with 10 molar equivalents of the acid chloride in pyridine gave122 the octabenzoate and the l,2,6,2, 3, 4, 6 -hepta-0-benzoyl derivative in the ratio of 5 6, and treatment of /3-maltose monohydrate with 8.8 molar equivalents of acetyl chloride in pyridine-toluene at 0° gave123 the 1,2,6,2, 3, 4, 6 -heptaacetate and the octaacetate in the ratio of 27 10. Under similar conditions of benzoylation, cellobiose was converted into its oc-... 

One interesting and, at first, surprising instance was described by Zemp-l n, Csiiros and Bruckner, who found that trimethylamine reacts with the heptaacetates of cellobiosyl bromide and of lactosyl bromide, respectively. Later work by Zemplen and Bruckner showed that the product of such reactions is the same as that obtained when dimethylamine is used. Thus, the cellobiose reaction product is JV,Af-dimethylcellobiosylamiue... 

Cellobiose phenylosazone when treated by Diels method yielded a monoanhydride in the form of a hydrate. The same product was also obtained from cellobiose phenylosazone heptaacetate by deacetylation. The anhydride gave a pentaacetate proving that an oxide ring system was present, and structure XXXIII was proposed although the possibility of 1,3-anhydro- (1,5-oxide), 1,3-anhydro- (2,6-oxide) and 1,3-anhydro- (2,5-oxide) structures could not be rigidly excluded. 

Lactose phenylosazone heptaacetate yielded lactose phenylosazone anhydride hydrate,a compound previously isolated by Fischer and by Diels and Meyer. This compound also yields a pentaacetate the same structural possibilities occur here as in the case of the cellobiose phenylosazone anhydride mentioned above. 

The deacylation of the octaacetates of cellobiose, lactose, maltose and melibiose with Aspergillus niger lipase leads to the formation of the respective carbohydrate heptaacetates with a free anomeric OH-group at Cl in high yield1230, 232]. With... 

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