4-Chloro-2-ethylpyrimidine-5-boronic acid is primarily used in organic synthesis, particularly in the field of medicinal chemistry. It serves as a key intermediate in the preparation of various pharmaceutical compounds. Its boronic acid group makes it a valuable reagent in Suzuki-Miyaura cross-coupling reactions, which are widely employed to form carbon-carbon bonds in the synthesis of complex organic molecules. This compound is often utilized in the development of drugs targeting specific biological pathways, including inhibitors for enzymes or receptors involved in diseases such as cancer, inflammation, and infections. Additionally, its pyrimidine core is a common structural motif in many bioactive molecules, making it a versatile building block for drug discovery and development.