Textbook Question
Using any necessary reagents, show how you would accomplish the following syntheses.
(b)
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26. Amines
Nitrogenous Nucleophiles
2:05 minutesProblem 68
Textbook Question
The synthesis of ⍺-hydroxy acids can be done starting with amino acids. Suggest a mechanism of the two-step transformation shown. [The alcohol oxygen is the same in the reactant and product.
Verified step by step guidance1
Step 1: Begin by examining the starting material, which is an amino acid with a carboxylic acid group, an amino group, and an alcohol group. The target molecule is an ⍺-hydroxy acid with a cyano group replacing the amino group.
Step 2: The first step involves the use of NaNO₂ and HCl. This combination is typically used for diazotization, where the amino group is converted into a diazonium salt. The diazonium salt is a key intermediate that can undergo various transformations.
Step 3: In the second step, NaCN is introduced. The diazonium salt can be displaced by a nucleophile, such as cyanide ion (CN⁻), resulting in the formation of a nitrile group. This step involves a nucleophilic substitution reaction where the diazonium group is replaced by the cyano group.
Step 4: Throughout the reaction, the alcohol group remains unchanged. The mechanism ensures that the alcohol oxygen in the reactant is the same in the product, maintaining the integrity of the ⍺-hydroxy acid structure.
Step 5: Finally, verify the transformation by comparing the structures. The amino group has been successfully replaced by a cyano group, and the alcohol group remains intact, resulting in the desired ⍺-hydroxy acid.
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2mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Amino Acid Structure and Reactivity
Amino acids are organic compounds that serve as the building blocks of proteins. They contain an amino group, a carboxyl group, and a side chain (R group) that determines their properties. Understanding the structure of amino acids is crucial for predicting their reactivity in chemical transformations, particularly in the synthesis of -hydroxy acids.
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Mechanism of Organic Reactions
The mechanism of an organic reaction describes the step-by-step process by which reactants are converted into products. This includes the breaking and forming of bonds, the movement of electrons, and the intermediates formed during the reaction. A clear understanding of reaction mechanisms is essential for proposing a plausible pathway for the transformation of amino acids into -hydroxy acids.
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Functional Group Interconversion
Functional group interconversion involves the transformation of one functional group into another within a molecule. In the context of synthesizing -hydroxy acids from amino acids, recognizing how to convert amino groups and carboxyl groups into hydroxyl groups is vital. This concept is key to understanding how the final product retains the same alcohol oxygen as the starting material.
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