Fluorine is the most electronegative element in the periodic table, and the fluorine atom has a small atomic radius, so fluorine-containing organic compounds have many wonderful properties. For example, the introduction of fluorine atoms or fluorine-containing groups into drug molecules can improve the permeability to cell membranes, metabolic stability and bioavailability; in addition, the introduction of fluorine atoms will improve the lipid solubility of the compound and promote its absorption in the body. The speed of delivery changes the physiological effect. In the field of medicinal chemistry, the introduction of fluorine atoms into organic molecules is an important direction for the development of new anticancer drugs, antitumor drugs, antiviral agents, anti-inflammatory drugs, and central nervous system drugs.
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.
A spiro compound is a polycyclic compound in which two monocyclic rings share one carbon atom; the shared carbon atom is called a spiro atom. Spiro compounds have rigid structures, stable structures, and have special properties that general organic compounds do not possess, such as anomeric effect, spiro conjugation and spiro hyperconjugation. Compared with the monocyclic structure or the planar aromatic structure, the spiro structure has a larger three-dimensional structure; the heterocyclic spiro structure is also regarded as the biological isostere of some groups, which can change the drug to a certain extent. The water solubility, lipophilicity, dominant conformation and ADMET properties of the molecule make the optimized lead molecule easier to drug. Therefore, spiro compounds occupy a very important position in drug development.