Benzoxazole is an aromatic organic compound with a molecular formula of C7H5NO, a benzoxazole ring structure, and an odor similar to pyridine. Although benzoxazole itself has little practical value, many benzoxazole derivatives are commercially important. As heterocyclic compounds, benzoxazoles are used in research as starting materials for the synthesis of larger, often biologically active structures. Its aromaticity makes it relatively stable, although as a heterocycle it has an active site that enables it to be functionalized.
Tetrahydroquinoline is one of the most important simple nitrogen heterocycles, widely found in nature and in a variety of pharmacologically active compounds. Tetrahydroquinoline is an important structure for the synthesis of various biologically active derivatives.