Aliphatic aglycone

The aglycon part of glycoside is often represented by monoterpenes, C13-norisoprenoids, benzene derivatives, and long-chain aliphatic alcohols (Fig. 18) [74, 75]. 

GlucuronidationJ Glucuronides can be prepared in moderate yield by reaction of an aliphatic alcohol with methyl 2,3.4-tri-O-acetylglucopyranuronate (I) in the presence of (CH,),SiOTf at 0°. P-Glucuronides (2) are usually formed exelusively or preferentially with nucleophilic aglycones. Weakly nucleophilic aglycones (e.g., phenols) do not react under these conditions. 

Most anthocyanidins and flavonols occur as glycosides in plants. The glycosides thus consist of the llavonoid unit (the aglycon) and one or more monosaccharides. The most common substitutions occur in the 3- and the 5-positions of the flavan structure for the anthocyanidins and in the 3-position for the flavonols. The sugar moiety may have one or more aliphatic or aromatic acids attached in an acyl linkage. 

The hydrolysis of disaccharides may be likened to the hydrolysis of an aliphatic glycoside the aglycon is, however, another sugar residue. It might, therefore, be expected that the nonreducing portion should have... 

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