Heptose diethyl dithioacetal

Anhydroaldopentose dithioacetals are the sole products from treatment of dithioacetals of D-ribose,207 D-xylose,207 and D-lyxose208 with sulfonyl chlorides in pyridine D-glycero-L,-manno-heptose diethyl dithioacetal yields a 4,7-anhydride209 under the same conditions however, dithioacetals of D-arabinose,210,211 L-arabinose,211-213 D-glucose,213,214 D-mannose,215-217 >glycero-D-gu lo-hepto se,209 2-... 

This work was followed by the detection of an aldoheptose in Escherichia coli products and the subsequent isolation of jj-glycero-i>-manno-heptoee by Weidel, again in connection with phage-receptor studies. The sugar was obtained from the lipocarbohydrate fraction of Escherichia coli B cell-membranes and was isolated, after acid hydrolysis, on a cellulose-powder column. In this case, sufficient of the product was obtained to show that the diethyl dithioacetal and its hexaacetate had equal but opposite optical rotations, as compared with those of the same derivatives prepared from authentic D-glyc o-n-manno-heptose. 

Attempts to separate the heptoses (43) and (44) as their diethyl dithioacetals were unsuccessful. 

Although the original paper reported1 isolation of diethyl dithioacetals of only one pentose, four hexoses, and a heptose, this reaction has subsequently been generalized, with examples ranging from trioses21 to octoses.22,23... 

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