Deoxyglycosides, hydrolysis

Deoxyglycosides are, in spite of the 2000-fold greater sensitivity against acid hydrolysis, only poor substrates for glycosidases, as shown by the... 

The additive nature of the polar effect of the hydroxyl groups is demonstrated by the gradual increase in the stability, toward acid hydrolysis, of compounds XXIV to XXIX and by the fact that the relative stabilities of the various 2-deoxyglycosides are the same as those of the fully hydroxyl-ated glycosides discussed in this article. 

Substituents on the glycose moiety can have a pronounced effect on the rate of hydrolysis of glycosides. Their effect can be due either to polar effects of the substituents or to resulting modifications of the conformational stability of the molecule. Distinguishing between steric and polar effects of substituents on the sugar moiety is difficult, as has already been pointed out for 2-deoxyglycosides (see pp. 54-57). 

The stability toward acid-catalyzed hydrolysis of the 6-amino-6-deoxy-D-glycosides has been reported -" (see, however, Ref. 121). The stability of the 6-amino-6-deoxyglycoside must be at least partly due to the shielding effect of the — NH3+ oup. Likewise, the acid stability of 6-deoxy-6-iodo-D-glucosides has been noted. -"... 

Another difficulty in making 2-deoxyglycosides is that acidic conditions may cause hydrolysis or anomerization, as these glycosides are much more susceptible to such conditions than are the correponding pyranosides having an oxygen or nitrogen function at C-2. 

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