Construction of Benzoxazole and Isoquinoline Compounds via Base-Mediated Cyclization of Amino Acid Derivatives.

Biological organisms contain bioactive macromolecules such as amino acids, which serve as basic materials for constructing cells and repairing tissues. Due to the unique properties of the fluorine atom, which can alter the structure of proteins and increase their lipophilicity, incorporating a fluorine atom into amino acids has become a research hotspot. In this study, ethyl 3-bromo-2-((diphenylmethylene)amino)-3,3-difluoropropanoate was synthesized from glycine derivatives. Under alkaline conditions, this compound reacted with 2-aminophenol to generate a benzoxazole-containing amino acid derivative. This method is simple to operate, without metal participation, and is performed under relatively eco-friendly reaction conditions, providing a novel approach for the synthesis of benzoxazole heterocycles.