Theory Exercises

Nitrogen Functional Groups

Nitrogen-containing organic compounds are those that contain one or more nitrogen atoms in their structure. Among the most important are amines, nitriles, and amides.

Amines

Amines are organic compounds derived from ammonia (NH₃) in which one or more hydrogens have been replaced by alkyl or aryl groups.

Classification of Amines

  • Primary amines (1°): One substituent on the nitrogen (R-NH₂)
  • Secondary amines (2°): Two substituents on the nitrogen (R-NH-R')
  • Tertiary amines (3°): Three substituents on the nitrogen (R-N(R')(R"))

Nomenclature of Amines

  1. -amine system: The main chain is named and the suffix -amine is added.
  2. N-substitution system: For secondary and tertiary amines, the prefix N- is used to indicate the substituents attached to the nitrogen.

Examples

Ethylamine

Ethylamine: primary amine with an ethyl group.

Diethylamine

Diethylamine: secondary amine with two ethyl groups.

Trimethylamine

Trimethylamine: tertiary amine with three methyl groups.

Nitriles

Nitriles are organic compounds that contain the functional group -C≡N (cyano).

Nomenclature of Nitriles

  1. -nitrile system: The main chain is named (counting the carbon of the -C≡N group) and the suffix -nitrile is added.
  2. -carbonitrile system: The main chain is named without counting the carbon of the -C≡N group and the suffix -carbonitrile is added.

Examples

Methanenitrile

Hydrocyanic acid or methanenitrile: the simplest nitrile.

Acetonitrile

Ethanitrile (acetonitrile): nitrile with two carbons in total.

Propionitrile

Propanenitrile (propionitrile): nitrile with three carbons in total.

Amides

Amides are organic compounds derived from carboxylic acids where the -OH group has been replaced by a -NH₂, -NHR, or -NRR' group.

Classification of Amides

  • Primary amides: R-CO-NH₂
  • Secondary amides: R-CO-NH-R'
  • Tertiary amides: R-CO-N(R')(R")

Nomenclature of Amides

  1. -amide system: The chain of the corresponding carboxylic acid is named and the ending -oic is replaced by -amide.
  2. N-substitution system: For secondary and tertiary amides, the prefix N- is used to indicate the substituents attached to the nitrogen.

Examples

Acetamide

Acetamide: primary amide derived from acetic acid.

N-methylacetamide

N-methylacetamide: secondary amide with a methyl group attached to the nitrogen.

N,N-dimethylpropanamide

N,N-dimethylpropanamide: tertiary amide with two methyl groups attached to the nitrogen.