Question

What is the core skeleton of tetracycline antibiotics?

• A. Four fused benzene rings
• B. Macrocyclic lactone
• C. Quinoline nucleus
• D. Phenothiazine nucleus

Hint:

Tetracyclines are named for their four fused ring system.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Tetracyclines are a group of broad-spectrum antibiotics. The prefix "tetra-" (four) and "-cycline" (cycle/ring) refers directly to their structure.
Step 2: Detailed Explanation:
1. Nucleus: The chemical name for the tetracycline skeleton is naphthacene.
2. Arrangement: Naphthacene consists of four fused rings arranged linearly. Although they are partially saturated and substituted with various functional groups, the basic scaffold is often described simplified as four fused rings (resembling fused benzene rings).
3. Others: Macrocyclic lactones are found in Erythromycin. Quinoline is found in Ciprofloxacin.
Step 3: Final Answer:
The fundamental skeleton of any tetracycline is a system of four fused linear rings.