Lawsone, found in the extract of henna, reacts with amino acid residues to give the characteristic color associated with henna tattoos. Suggest a mechanism for the reaction shown.
Ch. 24 - Benzene II: Reactions Influenced by the Aromatic Ring

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Mullins 1st Edition
Ch. 24 - Benzene II: Reactions Influenced by the Aromatic Ring
Problem 60
Mullins 1st Edition
Ch. 24 - Benzene II: Reactions Influenced by the Aromatic Ring
Problem 60Chapter 23, Problem 60
Sulpiride is an antipsychotic. Provide the reagents (a) and (b) used to complete the synthesis.

Verified step by step guidance1
Step 1: Analyze the first transformation. The starting material is a sulfonamide with a hydroxyl group. The product has an additional carbonyl group adjacent to the hydroxyl group, suggesting an acylation reaction. Consider using an acyl chloride or anhydride as reagent (a) to introduce the acyl group.
Step 2: Consider the mechanism for the acylation. The hydroxyl group can act as a nucleophile, attacking the electrophilic carbonyl carbon of the acyl chloride or anhydride, leading to the formation of an ester linkage.
Step 3: Analyze the second transformation. The intermediate product has a carbonyl group and the final product has an additional nitrogen-containing ring structure. This suggests a nucleophilic substitution reaction where the nitrogen atom of the ring structure attacks the carbonyl carbon.
Step 4: Consider the mechanism for the nucleophilic substitution. The nitrogen atom in the ring structure can act as a nucleophile, attacking the electrophilic carbonyl carbon, leading to the formation of an amide linkage.
Step 5: Identify reagent (b) as a nitrogen-containing compound, such as a cyclic amine, that can undergo nucleophilic attack on the carbonyl group to form the final product, Sulpiride.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Sulfonamide Chemistry
Sulfonamides are a class of organic compounds characterized by the presence of a sulfonyl group attached to an amine. They are crucial in pharmaceuticals due to their antibacterial properties. Understanding the reactivity and synthesis of sulfonamides is essential for designing drugs like Sulpiride, which involves the transformation of sulfonamide precursors.
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Amide Bond Formation
Amide bond formation is a fundamental reaction in organic chemistry, often used in the synthesis of pharmaceuticals. It involves the reaction between a carboxylic acid derivative and an amine, forming an amide linkage. This process is key in the synthesis of Sulpiride, where amide bonds are formed to build the drug's complex structure.
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Reagent Selection in Organic Synthesis
Choosing appropriate reagents is critical in organic synthesis to achieve desired transformations efficiently. Reagents are selected based on their ability to facilitate specific chemical reactions, such as oxidation, reduction, or functional group interconversion. In the synthesis of Sulpiride, selecting reagents (a) and (b) is crucial for progressing through the synthetic pathway to achieve the final product.
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Related Practice
Textbook Question
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Textbook Question
Synthesize the dye shown starting with aniline and naphthol using reactions from Chapters 23 and 24. [Hint. Start by identifying how each substituent might be installed and then plan the order of their introduction.]
Textbook Question
Phenol is synthesized from cumene via the scheme shown. Suggest the mechanism for each step of the reaction shown. [The oxygens have been screened in blue and orange to assist you.]
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Textbook Question
Phenol oxidation can be coupled with other reactions to form new C―C bonds using reactions studied previously. Predict the product of the following series of reactions.
(b)
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Textbook Question
Provide the reagents necessary to carry out the following synthesis. What is the purpose of steps (a) and (e)?
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