Chapter II: Nomenclature of Alcohols, Amines, Ketones, and Aldehydes

Overview

• Goal: Learn to name alcohols, amines, ketones, and aldehydes.
• Note: Keep using the naming rules from previous chapters.

Key Points

Root and Parent Names

• Root Name: Longest continuous carbon chain with a functional group.
• Parent Name: Used interchangeably with root name.
• Naming: Identify the longest carbon chain first.

Functional Groups as Suffixes

• Add suffixes to the root to indicate functional groups.
• Suffix Examples: -ol for alcohols, -amine for amines, -one for ketones, -al for aldehydes.

Naming Alcohols

• Identify the longest continuous carbon chain with the alcohol group attached.
• Replace the -e from the alkane name with -ol.
• Number the chain to give the hydroxyl group the lowest possible number.
• Example: pentane → pentenol → 2-pentanol.

Prefixes for Substituents

• Use prefixes for positions of substituents:
  • Hydroxy: -OH group as a substituent.
  • Amino: -NH₂ group as a substituent.
• Substituents are ordered based on alphabetical order in the final name.

Priority of Functional Groups

• Functional groups have a hierarchy of priorities:
  • Carboxylic acids > Esters > Aldehydes > Ketones > Alcohols > Amines > Alkenes/Alkynes > Ethers > Halides

Detailed Steps for Naming

1. Determine the highest priority functional group: Assign it the suffix.
2. Identify the longest chain or ring containing the highest priority functional group.
3. Drop the -e from the alkane/alkene name and add suffix.
4. Number the chain to give the highest priority functional group the lowest number.
5. Prefix the name with the position and name of other substituents.
6. Combine all parts: Prefix + Locator + Root + Suffix.

Examples with Alcohols and Amines

• Example molecule with alcohol and amine:
  • Naming: 4-amino-2-pentanol (aminos as substituents).
• Aldehyde and Alcohol: 3-hydroxybutanal (aldehyde priority over alcohol).
• Ketone and Alcohol: 4-hydroxy-2-pentanone (ketone priority over alcohol).

Stereochemistry and Double Bonds

• Stereochemistry: (R)-, (S)- for chiral centers.
• Double bonds: E/Z nomenclature for alkenes.
• Example: (E)-3,5-dimethyl-2-hexene.

Special Cases

• Cyclic aldehyde: cyclopentane carbaldehyde.
• Multiple functional groups: Double suffixes, retain the -e in alkane names.

Common Names and Trivial Names

• Formaldehyde for methanal.
• Acetone for propanone.
• Isopropyl alcohol for 2-propanol.

Degree of Alcohols and Amines

• Primary Alcohol: Attached to one carbon.
• Secondary Alcohol: Attached to two carbons.
• Tertiary Alcohol: Attached to three carbons.

Practice and Application

• Consistent practice of identifying longest chain and suffixes required.
• Using provided tables for suffixes and prefixes during exams.
• Remember priority rules for functional groups.

Practical Tip

• Trivial names are not to be memorized but to be recognized in context.
• Structural names will often be given and need to be interpreted correctly.

Summary

• Apply rules from previous chapters in addition to new rules for alcohols, amines, ketones, and aldehydes.
• Prioritize functional groups and use suffixes accurately.
• Practice frequently with various examples to familiarize with naming conventions.