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. 二> Chapter 7 10Chapter 7 10 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. =>