IUPAC Naming of Organic Compounds

Introduction

• Importance of IUPAC naming in exams.
• Aim to simplify IUPAC naming.
• Encouragement to interact with the content (quizzes and questions).

Basic Rules for IUPAC Naming

• Identify the longest continuous carbon chain.
• Number the carbon chain forward and backward.
• Determine the number of carbon atoms:
  • 1 Carbon: Meth-
  • 2 Carbons: Eth-
  • 3 Carbons: Prop-
  • 4 Carbons: But-
  • 5 Carbons: Pent-

Examples and Applications

Example 1: Ethane (C2H6)

• Longest chain: 2 carbons.
• Type of bond: Single bond (alkane).
• Name: Ethane.

Example 2: Propene (C3H6)

• Longest chain: 3 carbons.
• Type of bond: One double bond (alkene).
• Name: Propene.

Example 3: Pentane (C5H12)

• Longest chain: 5 carbons.
• Type of bond: Single bonds (alkane).
• Name: Pentane.

Example 4: Cyclopentane

• Structure: Cyclic with 5 carbons.
• Name: Cyclopentane.

Example 5: 2-Methylbutane

• Longest chain: 4 carbons (butane) with a methyl group.
• Name: 2-Methylbutane.

Example 6: Chloroalkanes

• Identify longest chain and halogen.
• Example: 1-Chloropentane.

Example 7: Benzene Derivatives

• Discussed with substituents and their positions.

Functional Groups and Their Priority

• Hierarchy of Functional Groups:

  1. Carboxylic Acid (COOH)
  2. Aldehyde (CHO)
  3. Ketone (C=O)
  4. Alcohol (OH)
  5. Alkene (C=C)
  6. Alkyne (C≡C)
  7. Halogens (F, Cl, Br, I)

• Example:

  • Pentanoic Acid with a chloro group: 4-Chloropentanoic Acid.

Special Cases

Naming Ketones and Aldehydes

• Aldehydes typically have the carbonyl at the end.
• Ketones have carbonyl between two carbons.
• Example: Propanone (acetone).

Conclusion

• Recap of the steps for IUPAC naming:

  1. Identify the longest carbon chain.
  2. Number it forwards and backwards.
  3. Identify functional groups and assign names.
  4. Use the priority list for numbering positions.

• Encouragement to practice and share knowledge.