A diazine in which the two nitrogen atoms are in the meta- positions; it is the basis of three of the bases found in DNA and RNA, thymine, uracil and cytosine
Any of a class of heterocyclic compounds with a ring structure of four carbon and two nitrogen atoms. The simplest member, pyrimidine itself (C4H4N2), is not common, but derivatives with the structure are. Examples include thiamine (vitamin B1), several sulfa drugs, barbiturates, and three of the bases in nucleic acids (cytosine, thymine, and uracil)
Any of a class of aromatic heterocyclic compounds containing a ring of four carbon atoms and two nitrogen atoms; especially the simplest one, C{4}H{4}N{2}, and three of the bases found in DNA and RNA, thymine, uracil and cytosine