Benzoxazole

Benzoxazole

Names
IUPAC name benzoxazole
Other names 1-Oxa-3-aza-1H-indene
Identifiers
CAS Number	273-53-0
ChEBI	CHEBI:38814
ChEMBL	ChEMBL451894
ChemSpider	8873
Jmol interactive 3D	Image
PubChem	9228
InChI InChI=1S/C7H5NO/c1-2-4-7-6(3-1)8-5-9-7/h1-5H Key: BCMCBBGGLRIHSE-UHFFFAOYSA-N InChI=1/C7H5NO/c1-2-4-7-6(3-1)8-5-9-7/h1-5H Key: BCMCBBGGLRIHSE-UHFFFAOYAP
SMILES n1c2ccccc2oc1
Properties
Chemical formula	C7H5NO
Molar mass	119.12 g·mol^−1
Appearance	white to light yellow solid
Melting point	27 to 30 °C (81 to 86 °F; 300 to 303 K)
Boiling point	182 °C (360 °F; 455 K)
Solubility in water	insol.
Hazards
Flash point	58 °C (136 °F; 331 K)
Related compounds
Related compounds	oxazole indole benzofuran
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Benzoxazole is an aromatic organic compound with a molecular formula C₇H₅NO, a benzene-fused oxazole ring structure, and an odor similar to pyridine.^[1][2] Alhtough benzoxazole itself is of little practical value, many derivatives of benzoxazoles are commercially important.

Being a heterocyclic compound, benzoxazole finds use in research as a starting material for the synthesis of larger, usually bioactive structures. Its aromaticity makes it relatively stable, although as a heterocycle, it has reactive sites which allow for functionalization.

Occurrence and Applications

It is found within the chemical structures of pharmaceutical drugs such as flunoxaprofen. Benzoxazole derivatives are also of interest for optical brighteners in laundry detergents.^[3] Benzoxazoles belong to the group of well-known antifungal agents with antioxidant, antiallergic, antitumoral and antiparasitic activity.^[4]

4 4'-bis(benzoxazolyl)-cis-stilbene is an intensely fluorescent and its derivatives are used as optical brighteners.

2 5-bis(benzoxazol-2-yl)thiophene is also an intensely fluorescent and its derivatives are used as optical brighteners, e.g. in laundry detergents.^[5]

See also

• Benzisoxazole, an analog with the nitrogen atom in position 2.
• Benzimidazole, an analog with the oxygen replaced by a nitrogen.
• Benzothiazole, an analog with the oxygen replaced by a sulfur.
• Benzopyrrole or indole, an analog without the oxygen atom.
• Benzofuran, an analog without the nitrogen atom.
• Benzoxazoline, which has one double bond reduced.
• Benzoxazolidinedione, which has both double bonds reduced.
• Benzoxazolidine, which has both double bonds reduced.
• Benzoxazolidinone
• Simple aromatic rings

References

1. Katritzky, A. R.; Pozharskii, A. F. (2000). Handbook of Heterocyclic Chemistry (2nd ed.). Academic Press. ISBN 0080429882.
2. Clayden, J.; Greeves, N.; Warren, S.; Wothers, P. (2001). Organic Chemistry. Oxford, Oxfordshire: Oxford University Press. ISBN 0-19-850346-6.
3. E. Smulders, E. Sung "Laundry Detergents, 2. Ingredients and Products" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2012. doi:10.1002/14356007.o15_013
4. Şener, E., Yalçin, İ. and Sungur, E.: QSAR of some antifungal benzoxazoles and oxazolo(4,5-b)pyridines against C. Albicans. Quant. Struct.-Act. Relat. 10 (1991) 223-228.
5. M. Amine Fourati, Thierry Maris, W. G. Skene, C. Géraldine Bazuin, and Robert E. Prud’homme "Photophysical, Electrochemical and Crystallographic Investigations of the Fluorophore 2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene" J. Phys. Chem. B, 2011, volume 115, 12362–12369.doi:10.1021/jp207136k