title: Carboxy beta-lactams by photochemical ring contraction.
mesh_terms: D002264:Carboxylic Acids; D002511:Cephalosporins / Q000138:chemical synthesis; D003500:Cyclization; D010406:Penicillins / Q000138:chemical synthesis; D010777:Photochemistry; D013237:Stereoisomerism; D047090:beta-Lactams
chemical_list: D002264:Carboxylic Acids; D002511:Cephalosporins; D010406:Penicillins; D047090:beta-Lactams