structural:summarization, structural:reformatting, information:extraction
Pyrimidine is an aromatic, heterocyclic, organic compound similar to pyridine (C5H5N). One of the three diazines, it has nitrogen atoms at positions 1 and 3 in the ring. The other diazines are pyrazine and pyridazine. In nucleic acids, three types of nucleobases are pyrimidine derivatives: cytosine (C), thymine (T), and uracil (U).