Organic Nomenclature – The
Basics
Organic Nomenclature
• Naming compounds that contain Carbon and
Hydrogen
• Hydrocarbons: Contain only H and C
Alkanes
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Saturated Hydrocarbons (Max. # of H)
Only single bonds
CnH2n+2 for chains
CnH2n for cyclic structures
Naming Unbranched Alkanes
• Determined by # of Carbons, end in -ane
1: meth2: eth3: prop4: butC6H14 : Hexane
CH4 : ?
5: pent6: hex7: sept8: oct
9: non10: dec-
C3H8 : Propane
C4H10 : ?
Branched Alkanes
• Alkyl Group: branch with ONLY H and C
• Methyl: 1 C: -CH3
• Ethyl: 2 C: -CH2CH3
• Propyl: 3 C: -CH2CH2CH3
Naming Alkanes
1) Find longest C chain containing the most
substituents, count C, write name
2) Number C from closest substituent
3) Name substituents in alpha order
-More than one of each type use di-, tri- prefixes
4) Indicate positions of substiuents
5) Add commas between #s and hyphens
between # & letter
Alkenes (pg. 79)
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Hydrocarbons with at least 1 double bond
CnH2n
Unsaturated Carbons
Prefixes are same as alkanes, ending –ene
C2H4 : ethene
C4H8 : butene
Alkynes
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Hydrocarbons with at least 1 triple bond
CnH2n-2
Unsaturated Carbons
Prefixes are same as alkanes, ending –yne
C3H4 : propyne
C4H6 : butyne
Naming Alkenes & Alkynes
• Follow Alkane Rules
• Looking for longest chain that contains double
bond (-ene) or triple (–yne)
• Multiple double or triple bonds add prefix (di-,
tri-) and location before ending
– Ex: Prop-1,2-diene or 1,2-propdiene