Classification of amides
Compounds containing amide bonds are called amides. Amides can be regarded as both nitrogen-containing derivatives of carboxylic acids and ammonia or amine derivatives. Amides can be classified according to their structure: amides, imides, lactams and N-substituted amides. The product in which the two hydrogen atoms in the ammonia molecule are replaced by an acyl group is called an imide, and the amide structure containing an amide bond is called a lactam; the product in which the hydrogen atom on the nitrogen atom of the amide molecule is replaced by a hydrocarbon group is called an N-substituted amide .