IUPAC Nomenclature Parent is longest chain containing the double bond. -ane changes to-ene (or-diene,-triene) Number the chain so that the double bond has the lowest possible number. In a ring,the double bond is assumed to be between carbon 1 and carbon 2. > Chapter 7 11 Chapter 7 11 IUPAC Nomenclature • Parent is longest chain containing the double bond. • -ane changes to –ene (or -diene, -triene). • Number the chain so that the double bond has the lowest possible number. • In a ring, the double bond is assumed to be between carbon 1 and carbon 2. =>