This slide discusses about Heterocyclic compound Oxazole. i.e oxygen and nitrogen atom in five membered ring.

1. Heterocyclic compound - Oxazole
Lecture by
S.Mathivanan.,M.Pharm
Asst Professor
Pharmacy

2. Oxazole is the parent compound for a vast class
of heterocyclic aromatic organic compounds.
These are azoles with an oxygen and a
nitrogen separated by one carbon.
Oxazoles are aromatic compounds but less so
than the thiazoles. Oxazole is a weak base; its
conjugate acid has a pKa of 0.8, compared to 7
for imidazole.

3. • The first oxazole was prepared in 1840 by Zinin, who
obtained the compound he called azobenzil from the
reaction of benzil with alcoholic ammonia.
• Japp's formulation was the first recognition of the
oxazole nucleus as an identity but six years later, in
1882, an independent series of observations led
Hantzsch to a similar formulation of the oxazole
nucleus.

5. • Natural products and their derivatives have always been
valuable sources for lead discovery in medicinal and
agricultural chemistry because their novel scaffolds can
provide modes of action different from those of existing
agents.
• Pimprinine is an indole alkaloid first isolated from the filtrates
of Streptomyces pimprina cultures in 1963.
• Members of this family display a range of biological activities,
such as antiepileptic effects, platelet-aggregation-inhibitory
effects, antitumor activity, and fungicidal activity.

6. Structural analog
• Isoxazole is an azole with an oxygen atom next
to the nitrogen. Isoxazole rings are found in
some natural products, such as ibotenic acid.
Amanita muscaria

7. Physical properties
• It is a liquid
• Boiling point 69.5°C
• Pyridine like odour
• Miscible with water and some other organic
solvents.
• Weakly basic (But slightly more than iso-
oxazole)
• Dipole moment : 1.5 D

8. CHEMICAL PROPERTIES

10. 1H-NMR spectra of Oxazole

11. NMR spectra
• Oxazole exhibits characteristic resonances in
1H NMR and 13C NMR spectra.
• 1H NMR – δ value between 7.00 to 8.00 ppm.
• 13C NMR – Shows typical aromatic resonances.
The shielding or de-shielding effect of C(2)
substitution on the C(4) and C(5) resonances is
< 2 ppm.

12. SYNTHESIS OF OXAZOLE

13. Fischer oxazole synthesis:
Discovered by Hermann Emil Fischer
in 1896.
Oxazole is formed by reacting
cyanohydrins and aldehyde in the presence of
anhyd. HCl

19. REACTIONS OF OXAZOLE

25. Linezolid
Napthooxazole

26. • oxazole compounds could readily bind with a
variety of enzymes and receptors in biological
systems and show broad biological activities
like antibacterial, antifungal, antiviral,
antitubercular, anticancer, anti-inflammatory
and so on.
• Up to now, a large number of oxazole-based
medicinal drugs have been extensively used in
clinic, such as Linezolid , Oxacillin ,
Sulfisoxazole , Raltegravir , Furazolidone as
well as Toloxatone

28. Ditazole: NSAIDs
Darglitazone : Thiazolidinedione class of drug.
Act as an agonist of peroxisome prolifrator
activated receptor-γ (PPAR-γ)

29. Thank you my dear students..!!!!