A penem is a type of

β-lactam A beta-lactam (β-lactam) ring is a four-membered lactam. A ''lactam'' is a cyclic amide, and ''beta''-lactams are named so because the nitrogen atom is attached to the β-carbon atom relative to the carbonyl. The simplest β-lactam possible is ...

with an unsaturated five-member

heterocycle A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and ...

containing a sulfur atom fused to the β-lactam ring. Penems do not occur naturally; all are synthetic. Related to penems are

carbapenem Carbapenems are a class of very effective antibiotic agents most commonly used for the treatment of severe bacterial infections. This class of antibiotics is usually reserved for known or suspected multidrug-resistant (MDR) bacterial infections. ...

s, which have a carbon atom in place of the sulfur atom. An example is

faropenem Faropenem is an orally active beta-lactam antibiotic belonging to the penem group. It is resistant to some forms of extended-spectrum beta-lactamase. It is available for oral use. Forms Faropenem was developed by Daiichi Asubio Pharma, which ...

Structure

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-lactamase Beta-lactamases, (β-lactamases) are enzymes () produced by bacteria that provide multi-resistance to beta-lactam antibiotics such as penicillins, cephalosporins, cephamycins, monobactams and carbapenems ( ertapenem), although carbapenems ...

s, 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.

Structure

References

Further reading