Chemical structure of Tetra cyclines

 Tetracyclines are a class of broad-spectrum antibiotics. They have a characteristic structure based on a linear fused tetracyclic core. Below are the chemical structures of four tetracyclines with their descriptions:

1. Tetracycline:

   • Formula: C₂₂H₂₄N₂O₈
   • Structure: Consists of four fused hydrocarbon rings (A, B, C, D) with various functional groups attached, including hydroxyl (OH), amine (NH₂), and keto (C=O) groups.

2. Doxycycline:

   • Formula: C₂₂H₂₄N₂O₈
   • Structure: Similar to tetracycline but lacks a hydroxyl group at position 6, making it more lipophilic and increasing oral absorption.

3. Minocycline:

   • Formula: C₂₃H₂₇N₃O₇
   • Structure: Contains a dimethylamino group at position 7 and lacks a hydroxyl group at position 5, improving penetration into tissues.

4. Oxytetracycline:

   • Formula: C₂₂H₂₄N₂O₉
   • Structure: It has an additional hydroxyl group at position 5, compared to tetracycline.

These tetracyclines share the same core structure, which consists of a fused four-ring system but vary in the attached side chains and functional groups that impact their pharmacokinetic properties.