Which of the following compounds is an enamine?

Options

A.
B.
C. `Ph - N = N - Ph`
D. `Ph - N = N - H`

Answer

To determine which of the given compounds is an enamine, we first need to understand the structure of an enamine.

### Step-by-Step Solution:

1. **Understanding Enamines:**
An enamine is a compound that contains a carbon-carbon double bond (C=C) adjacent to a nitrogen atom that is bonded to a carbon atom (C-N). The general structure of an enamine can be represented as:
\[ R_1C=C(R_2)N(R_3) \]
where R1, R2, and R3 can be hydrogen, alkyl, or aryl groups.

2. **Analyzing the Options:**
We need to examine each of the provided compounds to identify if they fit the structure of an enamine.

3. **Option 1:**
- Check the structure: If there is a double bond between two carbons and a nitrogen atom is attached to one of those carbons with a single bond.
- If the structure matches the enamine definition, then this option is an enamine.

4. **Option 2:**
- Check the structure: If both carbon atoms are single-bonded and nitrogen is double-bonded to one of the carbons.
- This does not fit the enamine definition.

5. **Option 3:**
- Check the structure: If nitrogen is doubly bonded to carbon.
- This does not fit the enamine definition.

6. **Conclusion:**
After analyzing all options, we find that only the first option has the correct structure of an enamine, which consists of a C=C double bond adjacent to a C-N bond.

### Final Answer:
The compound that is an enamine is **Option 1**.