Which of the following reaction does not occur?

Options

A.
B.
C.
D.

Answer

To determine which reaction does not occur among the given options, we need to analyze the oxidation potential of the compounds involved, particularly focusing on the presence of hydrogen atoms on the carbon atoms that are to be oxidized.

### Step-by-Step Solution:

1. **Identify the Reactants**: The question involves the oxidation of organic compounds using KMnO4 (Potassium permanganate), a strong oxidizing agent.

2. **Understand the Oxidation Requirement**: For a carbon atom to be oxidized to a carboxylic acid, it must have at least one hydrogen atom attached to it. This is crucial because the oxidation process typically converts alcohols or aldehydes (which have hydrogen) into carboxylic acids.

3. **Analyze Each Option**:
- **Option 1**: Contains a carbon with two hydrogen atoms. Since it has hydrogen, it can be oxidized.
- **Option 2**: Contains a carbon with one hydrogen atom. This also can be oxidized.
- **Option 3**: Contains a carbon with three hydrogen atoms. This carbon can also be oxidized.
- **Option 4**: Contains a carbon that is part of a benzene ring with three methyl (CH3) groups attached. This carbon does not have any hydrogen atoms attached to it, making it unable to undergo oxidation.

4. **Conclusion**: Since the fourth option has a carbon that lacks any hydrogen atoms, it cannot be oxidized by KMnO4. Therefore, the reaction in the fourth option does not occur.

### Final Answer:
The reaction that does not occur is from **Option 4**.

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