Phenanthrene

From Wikipedia, the free encyclopedia

Phenanthrene is a polycyclic aromatic hydrocarbon composed of three fused benzene rings--as the above formula shows. The name Phenanthrene is a composite of phenyl and anthracene. It provides the framework for the Steroids. In its pure form, it is found in cigarette smoke and is a known irritant, photosensitising skin to light.

Contents 1 Chemistry 1.1 Canonical forms of Phenanthrene 2 External links 3 References

[edit] Chemistry

A classical phenanthrene synthesis is the Bardhan-Sengupta Phenanthrene Synthesis (1932) ^[1]. In the second step of this reaction 9,10-dihydrophenanthrene is oxidized with elemental selenium.

Reactions of phenanthrene typically occur at the 9 and 10 positions. Some basic reactions:

• Organic oxidation to Phenanthrenequinone with chromic acid ^[2]
• Organic reduction to 9,10-dihydrophenanthrene with hydrogen gas and raney nickel ^[3]
• Electrophilic halogenation to 9-bromophenanthrene with bromine ^[4]
• Aromatic sulfonation to 2 and 3-phenanthrenesulfonic acids with sulfuric acid ^[5]
• Ozonolysis to diphenylaldehyde ^[6]

[edit] Canonical forms of Phenanthrene

Phenanthrene has five resonance structures, given below:

There seems no difference between Phenanthrenec3 and Phenanthrenec4 (except one viewed from "behind"). Is there a simple explanation of what is the difference, that could be given, or linked to, here?

[edit] External links

• Links to external chemical sources

[edit] References