D-Arabinose hexaacetate

Cleavage of the hexaacetyllactal with ozone gives crystalline 3-(/3-d-galactopyranosyl)-D-arabinose hexaacetate, deacetylation of which yields the crystalline sugar.49... 

The oxidation of hexaacetylmaltal with ozone yields 3-(a-D-gluco-pyranosyl)-D-arabinose hexaacetate, deacetylation of which leads to the free sugar itself (LXXVII).69... 

Ozonolysis of hexa-O-acetyllactal gives 3-0- -D-galactopyranosyl-D-arabinose hexaacetate. Hydroxylation of lactal with aqueous peroxy-benzoic acid led to the isolation of only one isomer, namely 4-0- -d-galactopyranosyl-D-mannose (53), although Watters and Hudson later... 

In 1934, Hudson and his group observed that treatment of a number of methyl D-aldohexopyranoside tetraacetates gave the a-D-aldohexopyranose pentaacetates on acetolysis with sulfuric acid as catalyst. Three years later, they observed that methyl jS-D-arabinopyranoside 2,3,4-triacetate gives 56% of alde%do-D-arabinose hexaacetate and 11% of /3-D-arabino-pyranose 1,2,3,4-tetraacetate the optical rotation of the mixture decreased steadily during the reaction. However, for the a-D-arabinoside, the rotation rose very sharply during the first minute and then fell more slowly. At the end of the reaction, the products were essentially those from the jS-D-glycoside at the point of maximum rotation, a 14% yield of methyl jS-D-arabinopyranoside was isolated, showing that anomerization can occur under these conditions, followed by subsequent acetolysis to the peracetate. 

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