Show how you would accomplish the following synthetic conversions.
(c) pentanoic acid → pentan-1-amine

Verified step by step guidance

1. Step 1: Convert pentanoic acid to pentanoyl chloride using thionyl chloride (SOCl₂). This reaction replaces the hydroxyl group (-OH) of the carboxylic acid with a chlorine atom, forming an acyl chloride.
2. Step 2: React pentanoyl chloride with ammonia (NH₃) to form pentanamide. This nucleophilic substitution reaction replaces the chlorine atom with an amide group (-CONH₂).
3. Step 3: Reduce pentanamide to pentan-1-amine using a reducing agent such as lithium aluminum hydride (LiAlH₄). This reduction converts the amide group (-CONH₂) to an amine group (-CH₂NH₂).
4. Step 4: Perform a workup step to neutralize the reaction mixture and isolate pentan-1-amine. Typically, this involves adding water or an acid to quench the reducing agent and purify the product.
5. Step 5: Confirm the structure of pentan-1-amine using spectroscopic techniques such as NMR or IR to ensure the desired product has been synthesized.

Key Concepts

Carboxylic Acids

Carboxylic acids are organic compounds characterized by the presence of a carboxyl group (-COOH). They are known for their acidic properties and can undergo various reactions, including reduction and conversion to amines. In this context, pentanoic acid serves as the starting material for the synthesis of pentan-1-amine.

Reduction Reactions

Reduction reactions involve the gain of electrons or the decrease in oxidation state of a molecule. In organic chemistry, carboxylic acids can be reduced to primary alcohols or amines using reducing agents such as lithium aluminum hydride (LiAlH4) or borane (BH3). Understanding the mechanism of these reactions is crucial for converting pentanoic acid to pentan-1-amine.

Amine Synthesis

Amines are organic compounds derived from ammonia by replacing one or more hydrogen atoms with alkyl or aryl groups. The synthesis of amines from carboxylic acids typically involves a two-step process: first, reduction to an alcohol, followed by further reduction to the corresponding amine. This transformation is essential for achieving the desired product, pentan-1-amine, from pentanoic acid.