Hydrolysis arylamides

Friedel-Crafts alkylations and acylations of N-arylamides also proceed normally. For example, benzoylation of acetanilide (iV-acetylaniline) under Friedel-Crafts conditions gives 4-aminobenzophenone in 80% yield after hydrolysis. 

This zinc-dependent enzyme [EC 3.4.11.1], also referred to as cytosol aminopeptidase, leucyl aminopeptidase, and peptidase S, catalyzes the hydrolysis of a terminal peptide bond such that there is a release of an N-terminal amino acid, Xaa-Xbb-, in which Xaa is preferably a leucyl residue, but may be other aminoacyl residues including prolyl (although not arginyl or lysyl). Xbb may be prolyl. In addition, amino acid amides and methyl esters are also readily hydrolyzed, but the rates with arylamides are exceedingly slow. The enzyme is activated by heavy metal ions. 

Although the structure of haptens exerts an important influence on catalysis by antibodies, stabilization of the transition state by catalytic antibodies cannot always and cannot fully explain all observations. Sometimes, in analogy to the evolution of enzyme function, antibodies can take mechanistically unexpected detours. As an example, the corresponding antibody catalyzes the hydrolysis of arylamides according to Figure 18.3 by a factor of 2.5 x 105 over background. 

Available evidence suggests that arylamide bonds generally are quite resistant to hydrolytic attack in plant tissues. A notable exception, however, is the substituted propionanilide propanil (2), which is rapidly hydrolyzed in resistant rice plants but not in susceptible weeds such as Echinochloa crus-galli (Figure 10.2). Hydrolysis of propanil is mediated by a specific... 

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