An aromatic is a particularly stable structure that is frequently seen in organic chemistry. Aromatics are planar, cyclic, fully conjugated systems with odd numbers of electron pairs in their conjugated π system. Benzene is the most common example of an aromatic molecule. It is a six-membered ring with alternating single and double bonds. It has three π bonds, and so it has three electron pairs in its π system.
There are a number of common derivatives of benzene with names that you should remember.
There is also a peculiar way of naming benzene derivatives that have two substituents on the benzene ring. The prefixes o-, m- and p- denote 1,2-disubstitution, 1,3-disubstitution and 1,4-disubstitution, respectively.
Draw the following compounds.
a) p-nitrotoluene b) o-chloroaniline c) m-methylphenol
d) m-chlorobenzyl alcohol e) o-bromobenzaldehyde f) p-fluorobenzoic acid
g) 2,4-dimethylphenol h) 2,5-dichlorotoluene i) 2,4,5-trimethylaniline
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