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Chemical structure of Oxazole


Systematic (IUPAC) name
PubChem         ?
Chemical data
Formula C3H3NO 
Molar mass 69.06
Complete data

Oxazole is the parent compound for vast class of heterocyclic aromatic organic compounds. These are azoles with an oxygen and a nitrogen separated by one carbon [1].


In biomolecules, oxazoles result from the cyclization and oxidation of serine or threonine nonribosomal peptides:

Oxazoles in biochemistry

Oxazoles are not as abundant in biomolecules as the related thiazoles with oxygen replaced by a sulfur atom.


Oxazoles are aromatic compounds but less so than the thiazoles. Oxazole is a weak base with pKa of conjugate acid of 0.8 compared to 7 for imidazole.

Organic synthesis

Classical oxazole synthetic methods in organic chemistry are

Other methods are reported in the literature.

oxazoline from propargyl amides Merkul 2006
Oxazoline Synthesis Continuous Reactor

Organic reactions

Oxazoline CAN oxidation
in the balanced half-reaction three equivalents of water are consumed for each equivalent of oxazoline generating 4 protons and 4 electrons the latter derived from CeIV.

See also


  1. Heterocyclic Chemistry TL Gilchrist, The Bath press 1985 ISBN 0-582-01421-2
  2. A new consecutive three-component oxazole synthesis by an amidation–coupling–cycloisomerization (ACCI) sequence Eugen Merkul and Thomas J. J. Müller Chem. Commun., 2006, 4817 - 4819, doi:10.1039/b610839c
  3. Fully Automated Continuous Flow Synthesis of 4,5-Disubstituted Oxazoles Marcus Baumann, Ian R. Baxendale, Steven V. Ley, Christoper D. Smith, and Geoffrey K. Tranmer Org. Lett.; 2006; 8(23) pp 5231 - 5234; (Letter) doi:10.1021/ol061975c
  4. They react together in the first phase in a continuous flow reactor to the intermediate enol and then in the second phase in a phosphazene base (PS-BEMP) induced cyclization by solid-phase synthesis.
  5. Ceric Ammonium Nitrate Promoted Oxidation of Oxazoles David A. Evans, Pavel Nagorny, and Risheng Xu Org. Lett.; 2006; 8(24) pp 5669 - 5671; (Letter) doi:10.1021/ol0624530