Question

hydrolysis of amides is an important reaction, because it represents the first step in the digestion of dietary protein. which of the following compounds is formed as a result of the hydrolysis of n,n - diethylpropanamide as shown below?
ch3ch2c(=o)n(ch2ch3)2 + h2o → hcl

Explanation:

Step1: Recall amide hydrolysis rule

In acidic hydrolysis of amides ($\text{HCl}$ - catalyzed here), the amide $(\text{R}-\text{CO}-\text{NR}'_2)$ breaks at the $\text{C}-\text{N}$ bond. The carbonyl - carbon bonds with the $\text{OH}$ from water to form a carboxylic acid, and the nitrogen bonds with the $\text{H}$ from water to form an amine salt.

Step2: Analyze $N,N -$diethylpropanamide hydrolysis

For $N,N -$diethylpropanamide $(\text{CH}_3\text{CH}_2\text{CO}-\text{N}(\text{CH}_2\text{CH}_3)_2)$, the products of acidic hydrolysis are propanoic acid $(\text{CH}_3\text{CH}_2\text{COOH})$ and diethylammonium chloride $((\text{CH}_3\text{CH}_2)_2\text{NH}_2^+\text{Cl}^-)$. But looking at the options in terms of the non - ionic parts, the carboxylic acid part is $\text{CH}_3\text{CH}_2\text{COOH}$ and the amine part is $(\text{CH}_3\text{CH}_2)_2\text{NH}$. When considering the non - salt form of the products before the acid - base reaction with the excess acid in the solution, the products are propanoic acid and diethylamine. The general reaction is $\text{CH}_3\text{CH}_2\text{CO}-\text{N}(\text{CH}_2\text{CH}_3)_2+\text{H}_2\text{O}\xrightarrow{\text{HCl}}\text{CH}_3\text{CH}_2\text{COOH}+(\text{CH}_3\text{CH}_2)_2\text{NH}_2^+\text{Cl}^-$.

Answer:

The carboxylic acid product formed is $\text{CH}_3\text{CH}_2\text{COOH}$ (propanoic acid) and the amine product (in non - salt form) is $(\text{CH}_3\text{CH}_2)_2\text{NH}$ (diethylamine). But if we consider the options based on the structure fragments, the correct structure related to the carboxylic acid part of the hydrolysis product is the one with the $\text{CH}_3\text{CH}_2\text{CO}-$ group. Without seeing the full - fledged options with proper labels, if we assume the options are in terms of the main products' structures, the carboxylic acid product of the hydrolysis of $N,N -$diethylpropanamide is propanoic acid $\text{CH}_3\text{CH}_2\text{COOH}$ (the structure with the $\text{CH}_3\text{CH}_2\text{CO}-$ group and a $\text{COOH}$ functional group). If we had to choose from the given unlabeled structures, we need to look for the structure with the $\text{CH}_3\text{CH}_2\text{CO}-$ carbonyl - containing fragment.