A lactam (the noun is a grammatical blend from lactone + amide) is a cyclic amide. Prefixes may indicate the ring size: beta-lactam (4-membered), gamma-lactam (5-membered), delta-lactam (6-membered ring). That order in the nomenclature is because beta β, gamma γ and delta δ are the second, third and fourth letters in the alphabetical order of the Greek alphabet.

Synthesis

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General synthetic methods exist for the organic synthesis of lactams.

• Lactams form by the acid-catalyzed rearrangement of oximes in the Beckmann rearrangement.
• Lactams form from cyclic ketones and ammonia in the Schmidt reaction.
• lactams form from cyclisation of amino acids.
• In iodolactamization Spencer Knapp, Frank S. Gibson Organic Syntheses, Coll. Vol. 9, p.516 (1998); Vol. 70, p.101 (1992) Online article an iminium ion reacts with an halonium ion formed in situ by reaction of an alkene with iodine.

  Reactions

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  • Lactams can polymerize to polyamides.

  See also

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  • Beta-lactam with a four-membered ring found in beta-lactam antibiotics.
  • Lactone, a cyclic ester.
  • Caprolactam

  References

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  External links

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  Functional groups | Amides

  Lactam | לקטם | ラクタム | Laktam