Lossen rearrangement

Lossen rearrangement
Named after Wilhelm Lossen
Reaction type Rearrangement reaction
Identifiers
RSC ontology ID RXNO:0000156

The Lossen rearrangement is the conversion of an acyl hydroxamate to an isocyanate and carboxylic acid side product.[1][2][3][4] The isocyanate can be used further to generate ureas in the presence of amines or generate amines in the presence of H2O.

Reaction mechanism

The acyl hydroxamate is first converted to its conjugate base. A concerted rearrangement event then occurs in which the amide substituent migrates to the amide nitrogen, the nitrogen donates a pair of electrons to form the isocyanate C=N double bond, and the N–O σ-bond breaks.

Historical references

  • Lossen, W. (1872). "Ueber Benzoylderivate des Hydroxylamins". Justus Liebigs Annalen der Chemie. 161 (2–3): 347–362. doi:10.1002/jlac.18721610219.
  • Lossen, W. (1875). "Ueber die Structurformel des Hydroxylamins und seiner amidartigen Derivate". Justus Liebigs Annalen der Chemie. 175 (3): 271–304. doi:10.1002/jlac.18751750303.
  • Lossen, W. (1875). "Methode, die Carboxylgruppe aromatischer Säuren durch die Amidgruppe zu ersetzen". Justus Liebigs Annalen der Chemie. 175 (3): 313–325. doi:10.1002/jlac.18751750305.

See also

References

  1. ^ Wang, Zerong (2010). Comprehensive organic name reactions and reagents. John Wiley & Sons, Inc. pp. 1772–1776. ISBN 9780471704508.
  2. ^ Yale, H. L. (1943). "The Hydroxamic Acids". Chem. Rev. 33 (3): 209–256. doi:10.1021/cr60106a002.
  3. ^ Bauer, L.; Exner, O. (1974). "The Chemistry of Hydroxamic Acids and N-Hydroxyimides". Angew. Chem. Int. Ed. Engl. 13 (6): 376. doi:10.1002/anie.197403761.
  4. ^ Shioiri, Takayuki (1991). "Degradation Reactions". Comprehensive Organic Synthesis. 6: 795–828. doi:10.1016/B978-0-08-052349-1.00172-4. ISBN 9780080359298.
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