Barbiturates, Hydantoins, and Imides

Schiff Base and Other Reactions Involving Carbon-Nitrogen Bond Cleavage 

Drug substances with carbohydrate moieties, such as digoxin,128 129 eliminate the carbohydrate group(s) due to acid-catalyzed hydrolysis. Nucleosides such as 5-azacytidine 

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Barbiturates, hydantoins, and imides contain functional groups related to amides but tend to be more reactive. Barbituric acids such as barbital, phenobarbital, amobarbital, and metharbital undergo ring-opening hydrolysis, as shown in Scheme 15.80-81 Decomposition products formed from these drug substances are susceptible to further decomposition reactions such as decarboxylation. The hydrolysis rates of these substances depend on the substituents Ri, R2, and R3. For some allylbarbituric acids, the effects of these substituents on hydrolysis rates can be explained in terms of Hammett s o value.82... 

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