2 Naming

Naming aromatic molecules Naming aromatic compounds can be complicated. The simplest molecules are derivatives of benzene and have benzene at the root of the name CH3 C2H5 Cl Br NO2 CO2H CHO Methylbenzene ethylbenzene chlorobenzene bromobenzene nitrobenzene benzenecarboxylic acid benzaldehyde N Goalby chemrevise.org If two or more substituents are present on the benzene ring, their positions must be indicated by the use of numbers. This should be done to give the lowest possible numbers to the substituents. When two or more different substituents are present, they are listed in alphabetical order and di, tri prefixes should be used. CH3 CH3 CH3 NO2 NO2 O2N COOH OH CH3 Cl 1,3-dimethylbenzene 1-chloro- 4-methylbenzene 4-hydroxybenzenecarboxylic acid 2,4,6-trinitromethylbenzene In other molecules the benzene ring can be regarded as a substituent side group on another molecule, like alkyl groups are. The C6H5 – group is known as the phenyl group. NH2 CH CH2 H3C CH CH2 CH3 C CH3 O H3C C O O phenylamine phenylethene 2-phenylbutane phenylethanone phenylethanoate