Predict the nature of the product `P`
`C_6 H_5 CONH_2 overset(Br_2// OD^(-) )(to) P`

Options

A. `C_6 H_5 NH_2`
B. `C_6 H_5 NHD`
C. `C_6 H_5 ND_2`
D. All of these

Answer

To predict the nature of the product `P` formed from the reaction of C₆H₅CONH₂ (aniline) with Br₂ in the presence of OD⁻, we can follow these steps:

### Step 1: Identify the Reactants
The reactant is C₆H₅CONH₂, which is an amide (specifically, benzamide).

### Step 2: Understand the Role of OD⁻
In the presence of OD⁻ (deuteroxide), a proton (H⁺) is abstracted from the amide nitrogen (NH₂), converting it to a negatively charged species (C₆H₅CONH⁻).

### Step 3: Reaction with Bromine
The negatively charged amide (C₆H₅CONH⁻) reacts with bromine (Br₂) to form an intermediate. This intermediate is C₆H₅C(=O)NBr, where bromine is now attached to the nitrogen.

### Step 4: Formation of Isocyanate
The intermediate can undergo rearrangement. The nitrogen atom has a vacant p-orbital, and the electron pair from the carbon can migrate to form an isocyanate (C₆H₅N=C=O).

### Step 5: Reaction with HDO
When HDO (deuterated water) is introduced, the isocyanate can react with it. The lone pair on the oxygen of HDO attacks the carbon of the isocyanate, leading to the formation of a compound that contains a nitrogen-carbon double bond and a deuterium atom.

### Step 6: Decarboxylation
The product can undergo decarboxylation, where carbon dioxide is eliminated, and a deuterium atom is transferred to the nitrogen atom.

### Step 7: Final Product
The final product formed is C₆H₅NHD, which is an amine with one deuterium atom attached to the nitrogen.

### Conclusion
Thus, the nature of the product `P` is C₆H₅NHD.