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.
Benzofurazans are important pharmaceutical intermediates. Benzofurazans are known bioisosteres of the nitro group. Both oxadiazoles and nitro groups have strong electron-withdrawing properties, but when optimizing drug-like properties such as activity, selectivity, and stability, the absence of standard charges in the oxadiazole structure may be more beneficial to drug products. What's more, nitro groups have been identified as toxic groups, and it is routine to remove or replace them in the early stages of drug development.