Mactam antibiotics

Enzymatic inactivation Some Mactam antibiotics Hydrolysis of the /3-laclam ring... 

Acquired resistance to /Mactam antibiotics can occur by three different mechanisms inactivation of the antibiotic, alteration of the target site and reduced permeability (Sanders 1992 Georgopapadakou 1993). 

Potentiometric enzyme-based electrodes have found application in clinical, pharmaceutical, food and biochemical analyses to enable the selective determination of a wide range of important enzyme substrates, including amino acids, esters, amides, acylcholines, /Mactam antibiotics, sugars, enantioselective drugs and many others [74]. 

G. Cacciatore, M. Petz, S. Rachid, R. Hakenbeck and A. Bergwerff, Development of an optical biosensor assay for detection of /Mactam antibiotics in milk using the penicillin-binding protein 2 x, Anal. Chim. Acta, 520 (2004) 105-115. 

Natural products and derivatives (such as sugars or /Mactam antibiotics) are treated as normal cyclic compounds. The natural product substructure is treated as a substituent or as a chiral auxiliary in the cyclic compound section. 

Cyclic amides are called lactams. A Creek letter is assigned to tire lactam to denote size, (i-lactams are 4-membered rings, y-lactams have 5 members, 5-lactams have 6 members, and so on. Although amides are the most stable of the carboxylic add derivatives, pdactams are highly reactive due to large ring strain. Nucleophiles easily react with (Mactams. p-lactams are found in several types of antibiotics. 

All technical work reported on the development of MIPs for clenbuterol and [3-lactam antibiotics was carried out on a recent European-funded project (FAIR CT96-1219), involving partners from University of Lund, University of Rome, Merck Eurolab (Prolabo), UNIR Association and Leatherhead Food Research Association Ltd (LFRA, Co-ordinator). The technical work on application of clenbuterol and /Mactam-MIPs to foods was carried out by Mr John Haines and Miss Francesca Aulanta of LFRA Ltd. 

DAST was also used for preparation of fluoromyoinositol148 and difluoroinositols (e.g. 13)149, which have an important role in calcium channels (equation 84). Various fluoropenicillins with profound antibiotic effects have been made by this method as well, without affecting the sensitive /Mactam ring (equation 85)150. 

The (2 + 2)-cycloaddition reactions of ketenes with heterocycles via an endocyclic imino group have contributed substantially to the synthesis of penicillin (92a) and cephalosporin C (93a) antibiotics and structurally related heterobicyclic /Mactams.7 11 Reactions with relatively stable ketenes, e.g., diphenylketene, have been reported as well as reactions of heterocycles with mixtures of acid chlorides and tertiary amines. 

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