Benzofuran

Benzofuran is the heterocyclic compound consisting of fused benzene and furan rings. This colourless liquid is a component of coal tar. Benzofuran is the structural nucleus (parent compound) 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.

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 (cyclication) of the resulting ether and decarboxylation.


 * Perkin rearrangement, where a coumarin is reacted with a hydroxide:
 * [[Image:Perkin rearrangement.svg|Perkin rearrangement|450px]]


 * Diels–Alder reaction of nitro vinyl furans with various dienophiles:
 * [[image:Benzofuran synthesis via a Diels-Alder reaction on vinyl furans.png|Diels–Alder reaction yielding a substituted benzofuran|450px]]


 * Cycloisomerization of alkyne ortho-substituted phenols:
 * [[image:Benzofurans via Cycloisomerization of Alkynes.png|Benzofurans via Cycloisomerization|400px]]

Related compounds

 * Substituted benzofurans
 * Dibenzofuran, an analog with a second fused benzene ring.
 * 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