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.<ref name=Ullmann>Template:Cite encyclopedia</ref>

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.<ref>Template:OrgSynth</ref>

• Perkin rearrangement, where a coumarin is reacted with a hydroxide:<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

Perkin rearrangement

• Diels–Alder reactionTemplate:Clarify of nitro vinyl furans with various dienophiles:<ref>Template:Cite journal</ref>

Diels–Alder reaction yielding a substituted benzofuran

• Cycloisomerization of alkyne ortho-substituted phenols:<ref>Template:Cite journal</ref>

Benzofurans via Cycloisomerization

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