Benzofuran

Benzofuran

Names
IUPAC name 1-Benzofuran
Other names Coumarone, benzo[b]furan
Identifiers
CAS Number	271-89-6
ChEBI	CHEBI:35260
ChEMBL	ChEMBL363614
ChemSpider	8868
DrugBank	DB04179
Jmol 3D model	Interactive image
KEGG	C14512
PubChem	9223
UNII	LK6946W774
InChI InChI=1S/C8H6O/c1-2-4-8-7(3-1)5-6-9-8/h1-6H Key: IANQTJSKSUMEQM-UHFFFAOYSA-N InChI=1/C8H6O/c1-2-4-8-7(3-1)5-6-9-8/h1-6H Key: IANQTJSKSUMEQM-UHFFFAOYAU
SMILES o2c1ccccc1cc2
Properties
Chemical formula	C8H6O
Molar mass	118.14 g·mol^−1
Melting point	−18 °C (0 °F; 255 K)
Boiling point	173 °C (343 °F; 446 K)
Hazards
Lethal dose or concentration (LD, LC):
LD50 (Median dose)	500 mg/kg (mice).[1]
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

Benzofuran is the heterocyclic compound consisting of fused benzene and furan rings. This colourless liquid is a component of coal tar. Benzofuran is the "parent" of many related compounds with more complex structures. For example, psoralen is a benzofuran derivative that occurs in several plants.

Production

Benzofuran is extracted from coal tar. It is also obtained by dehydrogenation of 2-ethylphenol.^[1]

Laboratory methods

Benzofurans can be prepared by various methods in the laboratory. Notable examples include:

• O-alkylation of salicylaldehyde with chloroacetic acid followed by dehydration of the resulting ether.^[2]

• Perkin rearrangement, where a coumarin is reacted with a hydroxide:^[3][4][5]

• Diels–Alder reaction of nitro vinyl furans with various dienophiles:^[6]

• Cycloisomerization of alkyne ortho-subtituted phenols:^[7]

Related compounds

• Furan, an analog without the fused benzene ring.
• Indole, an analog with a nitrogen instead of the oxygen atom.
• Benzothiophene, an analog with a sulfur instead of the oxygen atom.
• Isobenzofuran, the isomer with oxygen in the adjacent position.
• Aurone
• Thunberginol F

References

1. Collin, G.; Höke, H. (2007). "Benzofurans". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.l03_l01.
2. Burgstahler, A. W.; Worden, L. R. (1966). "Coumarone" (PDF). Org. Synth. 46: 28.; Coll. Vol. 5, p. 251
3. Perkin, W. H. (1870). "XXIX. On some New Bromine Derivatives of Coumarin". Journal of the Chemical Society 23: 368–371. doi:10.1039/JS8702300368.
4. Perkin, W. H. (1871). "IV. On some New Derivatives of Coumarin". Journal of the Chemical Society 24: 37–55. doi:10.1039/JS8712400037.
5. Bowden, K.; Battah, S. (1998). "Reactions of Carbonyl Compounds in Basic Solutions. Part 32. The Perkin Rearrangement". Journal of the Chemical Society, Perkin Transactions 2 1998 (7): 1603–1606. doi:10.1039/a801538d.
6. Kusurkar, R. S.; Bhosale, D. K. (1990). "Novel Synthesis of Benzosubstituted Benzofurans Via Diels-Alder Reaction". Synthetic Communications 20 (1): 101–109. doi:10.1080/00397919008054620. Retrieved 11 February 2014.
7. Fürstner, Alois and Davies, Paul (2005). "Heterocycles by PtCl2-Catalyzed Intramolecular Carboalkoxylation or Carboamination of Alkynes". Journal of the American Chemical Society 127 (43): 15024–15025. doi:10.1021/ja055659p. Retrieved 11 February 2014.