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Basic IUPAC Organic Nomenclature

Benzene as a substituent

  • Principle functional group is an alkene therefore suffix = -ene
  • The longest continuous chain is C2 therefore root = eth
  • The benzene ring is a substituent therefore = phenyl
  • Location of the phenyl group is unambiguous
phenylethene
phenyl system
C6H5CH=CH2
  • Principle functional group is an alkene therefore suffix = -ene
  • The longest continuous chain is C3 therefore root = prop
  • The benzene ring is a substituent therefore = phenyl
  • Numbering from the right as drawn to give the alkene the lowest locant = 1
  • Phenyl locant = 3
3-phenylpropene

phenyl system
C6H5CH2CH=CH2
  • Principle functional group is an alcohol therefore suffix = -ol
  • Hydrocarbon structure is an alkane therefore -an-
  • The longest continuous chain is C2 therefore root = eth
  • The benzene ring is a substituent therefore = phenyl
  • Numbering from the right as drawn to give the -OH the lowest locant = 1
  • Phenyl locant = 2
2-phenylethanol

phenyl system
C6H5CH2CH2OH



organic chemistry ©Dr. Ian Hunt, Department of Chemistry University of Calgary