Alkyl glucosides/glycosides alcohols

Commercial alkyl glycosides or, more specifically, alkyl glucosides are complex mixtures of acetals. Acetals, in general, are formed by the reaction of aldehydes and alcohols in the presence of a strong acid catalyst. The reaction involves an intermediate known as a hemiacetal. When acetaldehyde is dissolved in an excess of anhydrous ethyl alcohol in the presence of anhydrous hydrogen chloride, the following reactions occur ... 

The commercial production of alkyl glycosides is primarily the production of alkyl glucosides from a primary alcohol or primary alcohol mixture containing about 8-18 carbon atoms and a glucose source. Two of the most common processes for the reaction of an alcohol or alcohol mixture and a glucose source are described as follows ... 

The use of thiogtycosides in glycoside synthesis is referred to in a later section of this Chapter a novel development involves anodically oxidising the sulphur atom of 5-aryl 1-thio-O-glucopyranosides in the presence of alcohols to obtain alkyl glucosides (poor anomeric selectivity) together with diaryl disulphides. Mainly -products were obtained when the peracetylated thioglycosides were used. ... 

The first alkyl glucoside was synthesized and identified in the laboratory by Emil Fischer in 1893 [1], This process is now well known as the Fischer glycosida-tion and comprises an acid-catalyzed reaction of glycoses with alcohols. The structure of ethyl glucoside was defined correctly by Fischer, as may be seen from the historical furanosidic formula proposed ( Fischer projection ). In fact, Fischer glycosidation products are complex, mostly equilibrium mixtures of a/p-anomers and pyranoside/furanoside isomers which also comprise randomly linked glycoside oligomers (Fig. 1) [2]. 

Not surprisingly, trifluoromethanesulphonic acid can be used effectively as catalyst for the Fischer glycosidation of free sugars, and phosphorus oxychloride catalyses the reaction between sugar peracetates and alcohols. For aryl, alkyl and aralkyl D-glucoside esters /9-anomers (the kinetic products) are favoured if the reactions are carried out in benzene solution, whereas the more stable o-products predominate if no solvent is used. °... 

---