Dinitrophenyl glycosides, hydrolysis

Amide participation appears to be about as effective in specific acid-catalysed hydrolysis (of the methyl glycosides) as in spontaneous hydrolysis (of the 2,4-dinitrophenyl glycosides). There is some evidence for simultaneous general acid catalysis and amide participation in the hydrolysis of p-D-GlcNAcp-OoCfiH4COOH. 

Aryl glycosides, particularly those of acidic glycones, react readily in alkali, to the extent that deprotection of 2,4-dinitrophenyl glycosides is experimentally demanding. Most pathways involve participation by ionised hydroxyl groups. The effect of the aryl substituent on the rates of hydrolysis of aryl ot- and... 

From this it was concluded that electronic effects are the major reason that the stereoisomeric glycosides hydrolyze with different rates. This is also in agreement with the work of Namchuk et al. [27] who found that the rate of hydrolysis of dinitrophenyl glycosides depends mainly on electronic effects. In his work it was also shown that the variations in rate differences observed by different... 

Table 3 Relative hydrolysis rates of dinitrophenyl glycosides...

Hydrolysis and Related Reactions.— The hydrolysis of 2,4-dinitrophenyl jS-D-galactopyranoside at 25 °C has been found to be independent of pH between pH 1.6 and 8.4, whereas specific base-catalysis occurs above pH 8.4. Studies of related glycosides of pentoses, 6-deoxyhexoses, and 6-chloro-6-deoxyhexoses furnished evidence supporting the A-1 mechanism for the hydrolysis of these glycosides with acid. 

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