Crash Course Organic Chemistry: IUPAC Nomenclature

Introduction

• Language complications and chemistry lab terminology.
• Importance of IUPAC (International Union of Pure and Applied Chemistry) for standardization in chemistry.

Common vs Systematic Names

• Early chemistry used common names based on source or properties.
• Common names are still used due to simplicity and tradition (e.g., vanillin, cinnamaldehyde).
• IUPAC provides a systematic approach for naming chemicals.

IUPAC Naming Steps

1. Find the longest carbon chain
   • Assign a root name based on the number of carbons.
   • Root names: Monkeys Eat Purple Bananas (meth-, eth-, prop-, but-), pent-, hex-, hept-, oct-, non-, dec-, undec-, dodec-.
2. Identify the highest priority functional group
   • Add a suffix according to the functional group.
   • Hydrocarbons: Alkanes (-ane), Alkenes (-ene), Alkynes (-yne).
3. Identify and position substituents
   • Add numbered prefixes to the root name for substituents.

Detailed Naming Guidelines

• Alkanes: Single bonds, suffix -ane.
• Alkenes: Double bonds, suffix -ene, number carbons closest to the bond.
• Alkynes: Triple bonds, suffix -yne, similar numbering as alkenes.

Substituents

• Number the main chain for the lowest substituent positions.
• Prefixes for substituents: methyl, ethyl, propyl, etc.
• Halogens: change -ine to -o (e.g., chloro-, bromo-, iodo-).
• Multiple substituents: use di-, tri-, tetra- for multiples.

Complex Molecules

• Apply steps consistently for complex molecules with multiple functional groups.
• Example: 4-bromo-3-methylhept-1-ene-6-yne.

Lab Practice

• Understand common names and their systematic counterparts (e.g., dichloromethane vs. methylene chloride).

Conclusion

• Three steps to naming: Root name, suffix for functional groups, prefix for substituents.
• Next topic: Naming with heteroatoms.

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