Naming Aromatic Compounds Monosubstituted Benzenes Systematically named in same manner as other hydrocarbons benzene used as parent name CHsBr is bromobenzene C6H NO2 is nitrobenzene CH CH2CH2CH3 is propylbenzene Br NO2 CH2CH2CH3 Bromobenzene Nitrobenzene Propylbenzene
Monosubstituted Benzenes ▪ Systematically named in same manner as other hydrocarbons ▪ – benzene used as parent name ▪ C6H5Br is bromobenzene ▪ C6H5NO2 is nitrobenzene ▪ C6H5CH2CH2CH3 is propylbenzene Naming Aromatic Compounds
Naming Aromatic Compounds Arenes Alkyl-substituted benzenes Named depending on the size of the alkyl group Alkyl substituent smaller than the ring(6 or fewer carbons),named as an alkyl substituted benzene Alkyl substituent larger than the ring(7 or more carbons),named as a phenyl-substituted alkane Phenyl Derived from the Greek pheno("I bear light") Michael Faraday discovered benzene in 1825 from the oily residue left by illuminating gas used in London street lamps Used for the-CeH5 unit when the benzene ring is considered as a substituent Abbreviated as Ph or (Greek phi) Benzyl Used for the C6H5CH2-group
Arenes ▪ Alkyl-substituted benzenes ▪ Named depending on the size of the alkyl group ▪ Alkyl substituent smaller than the ring (6 or fewer carbons), named as an alkyl substituted benzene ▪ Alkyl substituent larger than the ring (7 or more carbons), named as a phenyl-substituted alkane Phenyl ▪ Derived from the Greek pheno (“I bear light”) ▪ Michael Faraday discovered benzene in 1825 from the oily residue left by illuminating gas used in London street lamps ▪ Used for the –C6H5 unit when the benzene ring is considered as a substituent ▪ Abbreviated as Ph or F (Greek phi) Benzyl ▪ Used for the C6H5CH2– group Naming Aromatic Compounds
Naming Aromatic Compounds 1CH3 CHCH2CH2CH2CH2CH3 CH2 234567 A phenyl group 2-Phenylheptane A benzyl group
Naming Aromatic Compounds
Naming Aromatic Compounds Disubstituted benzenes Named using one of the prefixes 1.ortho-(o-) Ortho-disubstituted benzene has two substituents in a 1,2 relationship 2.meta-(m-) ■ Meta-disubstituted benzene has its substituents in a 1,3 relationship 3.para-(p-） Para-disubstituted benzene has its substituents in a 1,4 relationship ortho-Dichlorobenzene meta-Dimethylbenzene para-Chlorobenzaldehyde 1,2 disubstituted (meta-xylene) 1,4 disubstituted 1,3 disubstituted
Disubstituted benzenes ▪ Named using one of the prefixes 1. ortho- (o-) ▪ Ortho-disubstituted benzene has two substituents in a 1,2 relationship 2. meta- (m-) ▪ Meta-disubstituted benzene has its substituents in a 1,3 relationship 3. para- (p-) ▪ Para-disubstituted benzene has its substituents in a 1,4 relationship Naming Aromatic Compounds
Naming Aromatic Compounds Benzenes with more than two substituents Named by numbering the position of each so that the lowest possible numbers are used The substituents are listed alphabetically when writing the name OH CH3 02N 1 CH3 CH3 NO2 6 CH3 H3C NO2 4-Bromo-1,2-dimethylbenzene 2,5-Dimethylphenol 2,4,6-Trinitrotoluene(TNT) Any of the monosubstituted aromatic compounds in Table 8.1 can serve as a parent name,with the principal substituent (-OH in phenol or-CH3 in toluene)attached to C1 on the ring
Benzenes with more than two substituents ▪ Named by numbering the position of each so that the lowest possible numbers are used ▪ The substituents are listed alphabetically when writing the name Any of the monosubstituted aromatic compounds in Table 8.1 can serve as a parent name, with the principal substituent (-OH in phenol or –CH3 in toluene) attached to C1 on the ring Naming Aromatic Compounds