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.
The use of azepane as a scaffold for drug discovery remains of interest. The azepane linker is the key to efficient activity. A number of seven-membered ring derivatives have been prepared or investigated for their potential or actual pharmacological properties. Examples include azaalkane derivatives as PKB (protein kinase B) inhibitors.