• Source: Lactam

A lactam is a cyclic amide, formally derived from an amino alkanoic acid through cyclization reactions. The term is a portmanteau of the words lactone + amide.




Nomenclature


Greek prefixes in alphabetical order indicate ring size.

This ring-size nomenclature stems from the fact that hydrolysis of an α-lactam gives an α-amino acid and that of a β-Lactam gives a β-amino acid, and so on.




Synthesis


General synthetic methods are used for the organic synthesis of lactams.




= Beckmann rearrangement

=
Lactams form by the acid-catalyzed rearrangement of oximes in the Beckmann rearrangement.




= Schmidt reaction

=
Lactams form from cyclic ketones and hydrazoic acid in the Schmidt reaction. Cyclohexanone with hydrazoic acid, forms ε - Caprolactum, which upon treatment with excess acid forms Cardiazole, a heart stimulant.




= Cyclization of amino acids

=
Lactams can be formed from cyclisation of amino acids via the coupling between an amine and a carboxylic acid within the same molecule.
Lactamization is most efficient in this way if the product is a γ-lactam. For example, Fmoc-Dab(Mtt)-OH, although its side-chain amine is sterically protected by extremely bulky 4-Methyltrityl (Mtt) group, the amine can still intramolecularly couple with the carboxylic acid to form a γ-lactam. This reaction almost finished within 5 minutes with many coupling reagents (e.g. HATU and PyAOP).




= Intramolecular nucleophilic substitution

=
Lactams form from intramolecular attack of linear acyl derivatives from the nucleophilic abstraction reaction.




= Iodolactamization

=
An iminium ion reacts with a halonium ion formed in situ by reaction of an alkene with iodine.




= Kinugasa reaction

=
Lactams form by copper-catalyzed 1,3-dipolar cycloaddition of alkynes and nitrones in the Kinugasa reaction




= Diels-Alder reaction

=
Diels-Alder reaction between cyclopentadiene and chlorosulfonyl isocyanate (CSI) can be utilized to obtain both β- as well as γ-lactam. At lower temp (−78 °C), β-lactam is the preferred product. At optimum temperatures, a highly useful γ-lactam known as Vince Lactam is obtained.




Lactam–lactim tautomerism


A lactim is a cyclic imidic acid compound characterized by an endocyclic carbon-nitrogen double bond. They are formed when lactams undergo tautomerization.




Reactions


Lactams can polymerize to polyamides.




See also


Lactone, a cyclic ester.
β-Lactam
β-Lactam antibiotics, which includes penicillins
2-Pyrrolidone
2-Piperidinone
Caprolactam




References






External links


Media related to Lactams at Wikimedia Commons

Kata Kunci Pencarian:

• Antibiotik laktam beta
• Laktam beta
• Amoksisilin-asam klavulanat
• Amoksisilin
• Metabolisme
• Sefamisin
• Piperasilin
• Avibaktam
• Streptococcus iniae
• Flukloksasilin
• Lactam
• Β-Lactam antibiotic
• Β-Lactam
• Beta-lactamase
• Penicillin
• Cephalosporin
• Β-Lactamase inhibitor
• Ojima lactam
• Amoxicillin
• Clavulanic acid