Introductory Organic Nomenclature

1
Introductory Organic Nomenclature

• Alkanes, Alkenes and Alkynes

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Alkanes

• CnH2n2
• All single bonds
• Saturated hydrocarbons
• Aliphatic or cyclic (note general formula
  changes when in ring form)

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Alkenes

• CnH2n
• One double bond
• unsaturated
• Aliphatic or cyclic

4
Alkynes

• CnH2n-2
• One triple bond
• unsaturated
• Aliphatic or cyclic

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Naming the chains
PREFIXES
Meth One carbon Eth Two carbons Prop Three
carbons But Four carbons Pent Five
carbons Hex Six carbons Hept Seven
carbons Oct Eight carbons Non Nine
carbons Dec Ten carbons
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What is this?
How about this one?
Number three?
The same thing?
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What if this happens?
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SIDE CHAINS

• One carbon ---- methyl
• Two carbons ---- ethyl
• Three carbons ---- propyl
• Four carbons ---- butyl
• Halogens ---- chloro, etc.

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SPECIAL RULES ABOUT ALKENES AND ALKYNES

• The multiple bond gets priority over side chains
• Put the multiple bond in the lowest possible
  position