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Basic IUPAC Organic Nomenclature

Alkynes

Nomenclature Formula 3D structure
Functional group suffix = -yne

Substituent prefix = alkynyl

Structural unit :  alkynes contain C≡C bonds.

  • Functional group is an alkyne, therefore suffix = -yne
  • The longest continuous chain is C4 therefore root = but
  • The first point of difference rule requires numbering from the right as drawn, the substituent locant is 1-
but-1-yne or 1-butyne
 



CH3CH2C≡CH
  • Functional group is an alkyne, therefore suffix = -yne
  • The longest continuous chain is C4 therefore root = but
  • The substituent is a C2 alkyl group i.e. a ethyl group
  • The first point of difference rule requires numbering from the right as drawn, the substituent locant is 2-
 but-2-yne or 2-butyne


 
CH3C≡CCH3


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