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Question #44025

Difficulty: 8/10 | 🟢 Free

The Question

Consider the following 8-step synthesis starting from Benzoic acid (\ceC6H5COOH\ce{C6H5COOH}): \ceBenzoicacid→2. \ceNaN3, Δ1. \ceSOCl2, refluxP→3. \ceH2O, ΔQ→4. \ce(CH3CO)2O, PyridineR\ce{Benzoic acid} \xrightarrow[\text{2. } \ce{NaN3}, \ \Delta]{\text{1. } \ce{SOCl2}, \ \text{reflux}} \mathbf{P} \xrightarrow{\text{3. } \ce{H2O}, \ \Delta} \mathbf{Q} \xrightarrow{\text{4. } \ce{(CH3CO)2O}, \ \text{Pyridine}} \mathbf{R} R→5. \ceCH3COCl, anhydrous \ceAlCl3 (excess)S (Major)→6. \ceH3O+, ΔT\mathbf{R} \xrightarrow{\text{5. } \ce{CH3COCl}, \ \text{anhydrous } \ce{AlCl3} \text{ (excess)}} \mathbf{S} \text{ (Major)} \xrightarrow{\text{6. } \ce{H3O^+}, \ \Delta} \mathbf{T} T→7. \cePhSO2Cl, aq. \ceNaOHU→8. \ceCH3IV\mathbf{T} \xrightarrow{\text{7. } \ce{PhSO2Cl}, \ \text{aq. } \ce{NaOH}} \mathbf{U} \xrightarrow{\text{8. } \ce{CH3I}} \mathbf{V} Identify the final major product V\mathbf{V}.

Options

  • A.

    NN-methyl-NN-(4-acetylphenyl)benzenesulfonamide

  • B.

    NN-methyl-NN-(3-acetylphenyl)benzenesulfonamide

  • C.

    NN-methyl-NN-(2-acetylphenyl)benzenesulfonamide

  • D.

    NN-(4-acetylphenyl)benzenesulfonamide

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Mechanism_Trap

Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.

Concepts Behind This Question

Friedel-Crafts on Carboxylic Acids|Reduction Selectivity (Sn/HCl vs LiAlH4)|Hinsberg Reagent Selectivity

Why This Question Is Tricky

Common Mistakes

This problem tests the strategic circumvention of 'catalyst poisoning' in Friedel-Crafts reactions.

Students often fall into the trap of assuming electrophilic aromatic substitution can occur directly on benzoic acid or unprotected aniline.

The sequence forces the realization that the acid must first be masked as an amine (via Curtius rearrangement), which must then be protected as an amide to enable para-directed acylation.

Finally, it tests the sequential reactivity of the Hinsberg test, where the resulting 1∘1^\circ sulfonamide salt acts as a nucleophile for further alkylation.

Quick Facts About This Question

Question Information

SubjectChemistry
ChapterAldehydes, Ketones, and Carboxylic Acids - Class 12
ConceptFriedel-Crafts on Carboxylic Acids
Difficulty8
Cognitive Load7
Target Solve Time160 sec
AccessFree