Many important pencilin type antibiotics possess a `beta`-lactum unit. Which of the following represents a `beta`-lactam ring?

Options

A.
B.
C.
D.

Answer

To solve the question regarding which structure represents a beta-lactam ring, we can follow these steps:

### Step 1: Understand the Structure of Beta-Lactam Ring
The beta-lactam ring is a four-membered cyclic structure that is essential in many penicillin-type antibiotics. It consists of:
- Three carbon atoms (C)
- One nitrogen atom (N)
- One carbonyl group (C=O)

### Step 2: Visualize the Beta-Lactam Ring
The beta-lactam ring can be represented as follows:
- A square-like structure where three corners are occupied by carbon atoms and one corner is occupied by a nitrogen atom.
- The carbonyl group (C=O) is attached to one of the carbon atoms.

### Step 3: Draw the Structure
To draw the beta-lactam ring:
1. Start with three carbon atoms arranged in a triangular shape.
2. Add a nitrogen atom to one of the corners.
3. Attach a double bond oxygen (C=O) to one of the carbon atoms.
4. Ensure that each carbon atom has the required number of hydrogen atoms to satisfy its tetravalency.

### Step 4: Analyze the Given Options
Now, look at the options provided in the question. You need to identify which option matches the structure of the beta-lactam ring as described.

### Step 5: Identify the Correct Option
Upon examining the options, you will find that:
- Option 2 matches the structure of the beta-lactam ring as it contains three carbon atoms, one nitrogen atom, and a carbonyl group.

### Conclusion
Thus, the correct answer is **Option 2**.

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