penem
{{Short description|Class of antibiotics}}
{{distinguish|penam}}
A penem is a type of β-lactam with an unsaturated five-member heterocycle containing a sulfur atom in a pentacyclic ring fused to the β-lactam ring. Penems do not occur naturally; all are synthetic.{{cite journal|journal=Antimicrobic Newsletter|title= The carbapenems and Penem Antibiotics—a brief review|author=Richard Wise|volume=7|issue= 10|year=1990|pages=73–78|
doi=10.1016/0738-1751(90)90045-E}} Related to penems are carbapenems, which have a carbon atom in place of the sulfur atom.{{cite web |url=http://www.medscape.com/viewarticle/464632_2 |title=Medscape.com }}
An example is faropenem.{{cite journal |vauthors=Milazzo I, Blandino G, Caccamo F, Musumeci R, Nicoletti G, Speciale A |title=Faropenem, a new oral penem: antibacterial activity against selected anaerobic and fastidious periodontal isolates |journal=Journal of Antimicrobial Chemotherapy |volume=51 |issue=3 |pages=721–5 |date=March 2003 |pmid=12615878 |doi= 10.1093/jac/dkg120|doi-access=free }}
Structure
{{See also|Beta-lactam#Nomenclature|l1=β-Lactam nomenclature}}
File:Faropenem.svg, a penem. A sulfur atom and a double bond are present in the pentacyclic ring.]]
File:Imipenem.svg. Imipenem has a sulfur atom that is not in the pentacyclic ring.]]
File:Penicillin-G.png, a penicillin. The double bond is absent in the pentacyclic ring.]]
Penem molecules do not occur naturally, and production of penems is an entirely synthetic process.
Five main penem subgroups — thiopenems, oxypenems, aminopenems, alkylpenems, and arylpenems — have been produced and are distinguished by the side chain (at position 2) of the unsaturated five-membered ring. One structurally distinct penem is BRL 42715. This molecule has no substitution at the above position, but has a bulky group attached to the β-lactam ring, and it displays effective inhibition of class C β-lactamases, but no antimicrobial activity.
One possible consequence of these structural differences of penems from other β-lactams may be reduced immunogenicity and immunogenic cross-reactivity.
{{clear}}
References
{{reflist}}
Further reading
- {{cite journal |vauthors=Sasaki A, Goda K, Enomoto M, Sunagawa M |title=Synthetic studies of carbapenem and penem antibiotics. II. Synthesis of 3-acetyl-2-azetidinones by (2 + 2) cycloaddition of diketene and Schiff bases |journal=Chemical & Pharmaceutical Bulletin |volume=40 |issue=5 |pages=1094–7 |date=May 1992 |pmid=1394625 |doi= 10.1248/cpb.40.1094|doi-access=free }}
{{Cell wall disruptive antibiotics}}