b - Lactam ring is present in
All penicillins have the basic structure. A thiazolidine ring (A) is attached to a b-lactam ring (B) that carries a secondary amino group (RNH-).Reference: Katzung&;s Pharmacology; 13th edition; Chapter 43; Beta-Lactam & Other Cell Wall- & Membrane-Active Antibiotics
Erythromycin
Penicillin
Tetracyclins
Chloramphenicol
general microbiology