Synthetic Thioglycosides

From their method of preparation these compounds are evidently 0-pyranosides, so it is of interest that, unlike all the natural thioglycosides, they are not hydrolyzed by the enzyme myrosin. The latter, therefore, must be either an a-thiopyranosidase or a thiofuranosidase. 

At about this same time, Schneider and Wrede prepared an acety-lated ghicoside (III) using the silver salt of the 0-phenyl ester of thio- 

It was not found possible to obtain the unacetylated compounds in these cases, since hydrolysis split the molecule and gave 1-thio-D-ghicose. 

In 1914, Fischer had treated acetobromo-D-glucose with silver thiocyanate and had obtained, as the acetyl derivative, the iso thiocyanate. This work was later extended by Fischer and by others and, fairly recently, by Muller and Wilhelms and by Wilhelms. These authors substituted potassium thiocyanate for the silver salt and, under the conditions employed, the product was the thiocyanate. However, when this was heated, it isomerized and the isothiocyanate, identical with that obtained by Fischer, resulted. 

Another series of interesting thiosugars was prepared by Schubert by the action of cysteine on the aldoses. By analogy with the structure assigned by this same author to the reaction product of cysteine with ordinary aldehydes, these new compounds may be formulated as the open chain forms  

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A further kind of modification that may be considered is the replacement of the glycosidic oxygen atom by other elements, notably sulfur and nitrogen. A variety of synthetic 1-deoxy-l-thioglycosides have been prepared and have been shown to be extremely stable toward acid hydroly-... 

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