Pyridazine, also known as o-diazobenzene, is a six-membered heterocyclic compound containing two nitrogen heteroatoms in the 1 and 2 positions with a special structure and a wide biological activity. Pyridazine is more and more popular in drug development, and a variety of pyridazine drugs have been developed and marketed. From the perspective of the therapeutic field, pyridazine drug molecules are mainly used for tumor treatment, but also involve in many therapeutic fields such as inflammation, hypertension and cardiovascular disease. With the increase and in-depth of research, pyridazine drugs will play more roles in the treatment of diseases.
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.