Carboxylic Acid Derivatives

What are carboxylic acid derivatives?

• Organic compounds

• can be derived from a carboxylic acid (–COOH) by replacing the –OH group with another group

What is the general structure of carboxylic acid derivatives?

• R–CO–Z

• Z is a leaving group (e.g., Cl, OR, NH₂, OCOR)

What are the major classes of carboxylic acid derivatives?

• Acid chlorides (acyl chlorides): R–COCl

• Anhydrides: R–CO–O–CO–R′

• Esters: R–COOR′

• Amides: R–CONH₂, R–CONHR′, or R–CONR′₂

• Nitriles: R–C≡N (sometimes included as a derivative)

How are carboxylic acid derivatives formed?

substitution reactions of a carboxylic acid
E.g.:

• Carboxylic acid + SOCl₂ → Acid chloride

• Carboxylic acid + alcohol → Ester (via Fischer esterification)

• Carboxylic acid + amine → Amide (via dehydration)

What is a nucleophilic acyl substitution?

The key rxn for CA derivatives

• A nucleophile attacks the carbonyl carbon —> the leaving group is replaced

How does reactivity of derivatives compare?

In decreasing reactivity toward nucleophilic attack: Acid chlorides > Anhydrides > Esters ≈ Carboxylic acids > Amides.

Why are acid chlorides most reactive?

• The Cl⁻ is a strong leaving group

• there’s little electron donation to stabilize the carbonyl.

What happens when derivatives undergo hydrolysis?

• They convert back to carboxylic acids using water,

  • especially in acidic or basic conditions.

What is saponification?

• Base-catalyzed ester hydrolysis

• typically producing a carboxylate salt + alcohol.

How can an ester be converted into an amide?

React the ester with ammonia or an amine → amide + alcohol.

Where are esters found in everyday life?

Flavors and fragrances, fats (triglycerides)

Why are amides important in biology?

• form the peptide bonds in proteins

  • linking amino acids.

What is acetyl-CoA?

• A biological thioester

• central to metabolism and energy transfer.

How are acid anhydrides used in chemistry?

As acylating agents — introducing acyl groups into other molecules.

What’s the key reaction of nitriles in organic synthesis?

Can be hydrolyzed to carboxylic acids or reduced to amines.