Naphthalene is a hydrocarbon produced by the distillation of coal tar and is an aromatic white crystalline substance. Naphthalene is the most abundant component in coal tar. It is used as an insect repellant and insect fumigant. The compound is used in the manufacture of celluloid, dyes, hydrogenated naphthalenes, oil fumes, smokeless powders and synthetic resins.
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.