1. Solid-Phase/Liquid-Phase Peptide Synthesis
As an efficient coupling agent, it catalyzes the formation of amide bonds (peptide bonds) between amino acids.
This is its most classic and primary application. It activates carboxylic acids, making them more reactive with amines (such as the amino group of another amino acid), reducing side reactions, and improving yield and purity.

2. General Synthesis of Amide Bonds
Used for the synthesis of various non-peptide amide compounds.
Amide bonds are widely present in medicinal chemistry and organic synthesis. HBTU can be used to connect carboxylic acids and amines to prepare biologically active amide molecules.

3. Esterification Reactions
Promotes the reaction of carboxylic acids with alcohols to form esters.
Under certain specific conditions, it can be used as an effective reagent for forming ester bonds.

4. Heterocyclic Compound Synthesis
Participates in the construction of heterocyclic structures that require the formation of amide bonds.
It plays a crucial role in the synthesis of certain complex drug molecules or natural products.