Using the pKa values listed in [TABLE 15.1], predict the products of the following reactions:
d.

Verified step by step guidance

1. Step 1: Identify the functional group in the given compound. The compound contains an amide functional group (-CONH2). Amides can undergo hydrolysis in the presence of a strong base like NaOH.
2. Step 2: Recall the mechanism of base-catalyzed hydrolysis of amides. In this reaction, the hydroxide ion (OH⁻) attacks the carbonyl carbon of the amide, leading to the cleavage of the C-N bond.
3. Step 3: Analyze the leaving group. The leaving group in this reaction is the amine (-NH2), which forms its conjugate acid, NH3, as shown in the table. The pKa of NH3 is 36, indicating it is a weak acid.
4. Step 4: Predict the products. The hydrolysis of the amide will yield a carboxylate ion (RCOO⁻) and ammonia (NH3). The carboxylate ion is formed because the reaction occurs under basic conditions, preventing the formation of the neutral carboxylic acid.
5. Step 5: Write the general reaction. The amide reacts with NaOH to produce a carboxylate salt (CH3CH2COO⁻Na⁺) and ammonia (NH3). This is consistent with the base-catalyzed hydrolysis mechanism.

Key Concepts

pKa and Acid Strength

pKa is a quantitative measure of the strength of an acid in solution; it indicates how easily an acid donates a proton (H+). Lower pKa values correspond to stronger acids, which are more likely to lose a proton. In nucleophilic acyl substitution reactions, the pKa of the leaving group’s conjugate acid is crucial for predicting the feasibility of the reaction, as a weaker acid (higher pKa) indicates a better leaving group.

Nucleophilic Acyl Substitution

Nucleophilic acyl substitution is a fundamental reaction in organic chemistry where a nucleophile attacks a carbonyl carbon, leading to the replacement of a leaving group. This reaction typically involves carboxylic acid derivatives, such as esters or anhydrides, and is influenced by the stability of the leaving group and the nucleophile's strength. Understanding this mechanism is essential for predicting the products of the reaction.

Leaving Groups

A leaving group is an atom or group that can depart from the parent molecule during a chemical reaction, taking with it the electrons that were shared with the parent. The ability of a leaving group to stabilize the negative charge after departure is critical; good leaving groups are typically weak bases (high pKa values for their conjugate acids). In the context of the provided reaction, the nature of the leaving group will significantly affect the reaction's outcome.