A penicillin is a member of a family of drugs that have a

Options

A. four membered cyclic amide fused to a five membered thiazole ring
B. three membered cyclic amide fused to a five membered thiazole ring
C. four membered cyclic amide fused to a four membered thiazole ring
D. five membered cyclic amide fused to a five membered thiazole ring

Answer

### Step-by-Step Solution:

1. **Understanding Penicillin**:
- Penicillin is an antibiotic that belongs to a class of drugs known as beta-lactam antibiotics. It is derived from Penicillium fungi and is used to treat bacterial infections.

2. **Analyzing the Structure**:
- The structure of penicillin includes a four-membered ring known as a beta-lactam ring. This ring is crucial for its antibacterial activity.
- Additionally, penicillin contains a thiazolidine ring, which is a five-membered ring that includes sulfur.

3. **Identifying Functional Groups**:
- Within the structure, there are important functional groups:
- An amide group (NH) is present, which contributes to the drug's properties.
- A carboxylic acid group (-COOH) is also part of the structure.

4. **Classifying the Rings**:
- The four-membered ring is classified as a cyclic amide (beta-lactam).
- The five-membered ring containing sulfur is classified as a thiazolidine ring.

5. **Choosing the Correct Option**:
- Based on the structural analysis, the correct classification of penicillin is that it contains a four-member cyclic amide and a five-member thiazolidine ring.

### Conclusion:
- The correct answer is that penicillin is a member of a family of drugs that have a **four-member cyclic amide** and a **five-member thiazolidine ring**.