The molecular structure of cyclobutane has four carbon atoms, and its four carbon atoms are not in the same plane, which is the folded conformation of cyclobutane. Cyclobutane itself is not of commercial or biological interest, but more complex derivatives are important in biology and biotechnology. Currently, nine FDA-approved drugs contain the cyclobutane structure. From the perspective of therapeutic areas, cyclobutyl drugs are mainly distributed in popular areas such as tumors, neurological diseases, infectious diseases, endocrine and metabolic diseases.
Naphthyridine is a class of aromatic heterocyclic compounds whose chemical formula is C8H6N2. They consist of naphthalene bicyclic rings in which two carbon atoms are replaced by nitrogen atoms. There are ten isomers of naphthyridine, because naphthyridine has two benzene rings, has strong π-π conjugation, and has better luminescence properties. Common naphthyridines are 1,8-naphthyridines. There are many kinds of 1,8-naphthyridine derivatives, and they are widely used.