Examples include: 5-Fluorouracil (5-FU): A pyrimidine analog used in the treatment of various cancers, including colorectal, breast, and head and neck cancers. Cytarabine (Ara-C): A cytosine analog ...

This diagram depicts the chemical structure of pyrimidine, a six-membered aromatic ring with two nitrogen atoms at positions 1 and 3 (highlighted in blue). The remaining positions are occupied by ...