Münchnone

Münchnone is a mesoionic heterocyclic aromatic chemical compound.

Other Names

In addition to the trivial name münchnone, this molecule has also been referred to as a:

• muenchnone
• munchnone (umlaut omitted)
• 1,3-oxazolium-5-oxide
• 1,3-oxazolium-5-olate
• anhydro-5-hydroxy-1,3-oxazolium hydroxide
• 5-hydroxy-1,3-oxazolium hydroxide, inner salt

Discovery and Utility

The first preparation of a münchnone derivative was reported in 1958 by Lawson & Miles by cyclodehydration of 2-Pyridone-N-acetic acid with acetic anhydride.^[1] The azomethine ylide reactivity of münchnones, and their reaction with [alkyne|alkynes]] in the synthesis of pyrroles, was first published by Huisgen et. al.^[2][3] The Huisgen group followed up with a thorough investigation of the chemical properties, reactivity, and utility of münchnones towards the synthesis of many other products.^[4][5] As such, they are typically credited for the discovery of Münchnones. While certain substituted münchnones are stable and easily isolated, the majority, including the parent münchnone itself, are unstable. Münchnones are typically used as 1,3-dipolar cycloaddition substrates in the synthesis of pyrroles by their in situ generation in the presence of alkynes.

Chemical structure

See also

• Sydnone
• Sydnone imine

References

1. ^ Lawson, A.; Miles, D. H. Chem. Ind. (London) 1958, 461.
2. ^ Huisgen, H.; Gotthardt, H.; Bayer, H. O. Angew. Chem., Int. Ed. Engl. 1964, 3, 135. (doi:10.1002/anie.196401353)
3. ^ Huisgen, H.; Gotthardt, H.; Bayer, H. O.; Schaefer, F.C. Angew. Chem., Int. Ed. Engl. 1964, 3, 136. (doi:10.1002/anie.196401361)
4. ^ Gingrich, H. L.; Baum, J. S. In Oxazoles, Chemistry of Heterocyclic Compounds; Turchi, I. J., Ed.; Wiley: New York, 1986; Vol. 45.
5. ^ Gribble, G. W. In Oxazoles: Synthesis, Reactions, and Spectroscopy, A; Palmer, D. C., Ed.; Wiley: New York, 2003; Vol. 60.