Thiophene is a five-membered heterocyclic compound containing a sulfur heteroatom with the molecular formula C4H4S. Thiophene is aromatic and is very similar to benzene; electrophilic substitution reaction is easier than benzene, and it is mainly substituted at the 2-position. Thiophene ring system has certain stability to oxidant.
Pyrimidine, also known as 1,3-diazobenzene, is a heterocyclic compound with the chemical formula C4H4N2. Pyrimidine is formed by substituting 2 nitrogen atoms for 2 carbons in the meta-position of benzene. It is a diazine and retains its aromaticity. Derivatives of pyrimidine widely exist in organic macromolecular nucleic acids, and many drugs also contain pyrimidine rings. In nucleic acids, three nucleobases are pyrimidine derivatives: cytosine, thymine and uracil. There are a variety of pyrimidine-containing drugs on the market, most of which are kinase inhibitors.
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.
Tetrahydrofuran is a heterocyclic organic compound with the molecular formula C4H8O. Tetrahydrofuran belongs to ethers and is the complete hydrogenation product of furan. It is a colorless, water-miscible organic liquid with small viscosity at normal temperature and pressure. Because of its long liquid range, it is a commonly used medium polar aprotic solvent. Its main use is as a precursor of high molecular polymers.