Ch. 19 - Amines

Wade9th EditionOrganic ChemistryISBN: 9780135213728Not the one you use?Change textbook

Wade 9th Edition

Ch. 19 - Amines

Problem 48a

Chapter 19, Problem 48a

Several additional amine syntheses are effectively limited to making primary amines. The reduction of azides and nitro compounds and the Gabriel synthesis leave the carbon chain unchanged. Formation and reduction of a nitrile adds one carbon atom. Show how these amine syntheses can be used for the following conversions.
(a) allyl bromide → allylamine

Verified step by step guidance

Step 1: Begin by understanding the problem. The goal is to convert allyl bromide (CH2=CH-CH2-Br) into allylamine (CH2=CH-CH2-NH2). This involves replacing the bromine atom with an amine group (-NH2).

Step 2: Choose an appropriate synthesis method. Since the Gabriel synthesis is effective for producing primary amines without altering the carbon chain, it is a suitable choice for this conversion.

Step 3: In the Gabriel synthesis, use potassium phthalimide (C8H5NO2K) to react with allyl bromide. This forms an N-alkylphthalimide intermediate, where the bromine atom is replaced by the phthalimide group.

Step 4: Hydrolyze the N-alkylphthalimide intermediate using a strong base, such as NaOH, or acidic conditions, such as HCl. This step cleaves the phthalimide group and releases the primary amine (allylamine).

Step 5: Verify the product structure. Ensure that the final product is allylamine (CH2=CH-CH2-NH2), with the carbon chain unchanged and the bromine atom replaced by the amine group.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Amine Synthesis Methods

Amine synthesis methods are various chemical reactions used to produce amines, which are organic compounds derived from ammonia. Key methods include the reduction of azides and nitro compounds, as well as the Gabriel synthesis. Understanding these methods is crucial for determining how to convert specific organic substrates, like allyl bromide, into the desired amine product.

Reduction Reactions

Reduction reactions involve the gain of electrons or hydrogen, or the loss of oxygen, resulting in the conversion of functional groups. In the context of amine synthesis, reducing agents can convert nitro groups or azides into amines without altering the carbon skeleton. This principle is essential for transforming allyl bromide into allylamine while maintaining the integrity of the carbon chain.

Nitrile Formation and Reduction

The formation of nitriles involves the introduction of a cyano group (-C≡N) into a molecule, which can subsequently be reduced to form primary amines. This process adds a carbon atom to the chain, making it a valuable strategy in amine synthesis. Understanding how to manipulate nitriles is important for achieving specific conversions, such as from allyl bromide to allylamine.

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Related Practice

Textbook Question

The two most general amine syntheses are the reductive amination of carbonyl compounds and the reduction of amides. Show how these techniques can be used to accomplish the following syntheses.

(b) benzaldehyde → benzylamine

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Textbook Question

Several additional amine syntheses are effectively limited to making primary amines. The reduction of azides and nitro compounds and the Gabriel synthesis leave the carbon chain unchanged. Formation and reduction of a nitrile adds one carbon atom. Show how these amine syntheses can be used for the following conversions.

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Textbook Question

Show how you can synthesize the following tertiary amine three different ways, each using a different secondary amine and adding the final substituent by (b) acylation–reduction (3 ways).

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Textbook Question

The two most general amine syntheses are the reductive amination of carbonyl compounds and the reduction of amides. Show how these techniques can be used to accomplish the following syntheses.

(d) cyclohexanone → N-cyclohexylpyrrolidine

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Textbook Question

Show how you can synthesize the following tertiary amine three different ways, each using a different secondary amine and adding the final substituent by

(a) reductive amination (3 ways).

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Textbook Question

The two most general amine syntheses are the reductive amination of carbonyl compounds and the reduction of amides. Show how these techniques can be used to accomplish the following syntheses.

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