Best reagent for nuclear iodination of aromatic compounds is

Options

A. `Ki//CH_(3)COCH_(3)`
B. `I_(2)//CH_(3)CN`
C. `KI//CH_(3)COOH`
D. `I_(2)//HNO_(3)`

Explanation

To determine the best reagent for nuclear iodination of aromatic compounds, we can follow these steps:

### Step 1: Understand Nuclear Iodination
Nuclear iodination refers to the substitution reaction where an iodine atom replaces a hydrogen atom on an aromatic ring. This process is essential in organic synthesis for the functionalization of aromatic compounds.

**Hint:** Nuclear iodination involves substituting an iodine atom for a hydrogen atom in an aromatic compound.

### Step 2: Identify Common Reagents
Common reagents for iodination include iodine (I2) and various iodinating agents. However, not all of them are effective for nuclear iodination of aromatic compounds.

**Hint:** Consider the effectiveness of different iodinating agents in aromatic systems.

### Step 3: Analyze the Role of HI
In the context of nuclear iodination, HI (hydroiodic acid) is produced during the reaction. HI is a strong reducing agent that can reduce iodobenzene back to benzene if not controlled properly.

**Hint:** Recognize that HI plays a dual role: it can facilitate iodination but also reduce iodobenzene back to benzene.

### Step 4: Consider the Best Reagent
The best reagent for nuclear iodination is I2 in the presence of a catalyst such as hydrazoic acid (HN3). This combination allows for effective iodination while minimizing the risk of reduction back to benzene.

**Hint:** Look for a reagent that combines iodine with a stabilizing agent to enhance iodination efficiency.

### Step 5: Conclusion
Thus, the best reagent for nuclear iodination of aromatic compounds is I2 in the presence of HN3.

**Final Answer:** The best reagent for nuclear iodination of aromatic compounds is I2 in the presence of HN3.

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