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Question #44354
The Question
Compound \textbf{P} (4-fluoro-3,5-dimethyl-2-nitrobenzoyl chloride) is treated with 1 equivalent of in at to yield compound \textbf{Q}. Subsequently, \textbf{Q} is heated with excess in a sealed tube at to yield the major product \textbf{R}. Identify \textbf{R}.
Options
- A.
N-methyl-4-(methylamino)-3,5-dimethyl-2-nitrobenzamide
- B.
Methyl 4-(methylamino)-3,5-dimethyl-2-nitrobenzoate
- C.
N-methyl-4-fluoro-3,5-dimethyl-2-nitrobenzamide
- D.
N-methyl-4-methoxy-3,5-dimethyl-2-nitrobenzamide
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
Nucleophilic Aromatic Substitution (SNAr)|Nucleophilic Acyl Substitution
Why This Question Is Tricky
Common Mistakes
The question tests the student's ability to evaluate competing electrophilic sites and recognize the profound impact of 3D molecular geometry on electronic effects.
The 'Hidden Variable' is the Steric Inhibition of Resonance (SIR) on the nitro group.
Students typically see an aryl fluoride ortho to a nitro group and immediately predict SNAr, especially under high heat with a nucleophile.
They fail to account for the ortho-bulky groups (ester and methyl) forcing the nitro group out of coplanarity, thereby shutting down its effect and rendering the aryl fluoride inert.
Additionally, the lack of adjacent protons prevents the benzyne pathway, leaving ester amidation as the sole viable reaction.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Haloalkanes and Haloarenes - Class 12 |
| Concept | Nucleophilic Aromatic Substitution (SNAr) |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |