Pyrimidine- Definition, Properties, Structure, and Functions

Pyrimidine is a heterocyclic aromatic compound composed of carbon and nitrogen atoms in a six-membered ring.

  • Pyrimidine derivatives are also known as pyrimidine, which consists of three nitrogen bases along with the two purines and is the building block of both deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
  • The pyrimidine nitrogen bases are derived by adding other functional groups to the pyrimidine compounds.
  • Thymine is the pyrimidine derivative found in the DNA only, whereas Uracil is found in the RNA only.
  • The melting point of Pyrimidine is 20-22 degrees Celsius.
  • On catabolism, it produces carbon dioxide, beta-amino acids, and ammonia.

Structure of Pyrimidine

  • Pyrimidine consists of four carbon atoms, two nitrogen atoms, and the hydrogen atoms attached to each carbon atom.
  • The alternating single and double bond is present between the carbon and the nitrogen atoms.
  • The alternating single and double bond causes the ring to be very stable, and also it allows for resonance and aromaticity.
  • Various other derivatives can be derived by adding one or more other functional groups.
  • The pyrimidine derivative retains the six-membered ring, but the modification and complex structure are formed by adding a few atoms to the nucleic acids.
  • Drugs and Vitamins generally have a complex structure.

Functions of Pyrimidine

  • Pyrimidine and its derivative are found in nucleic acids, vitamins, amino acids, antibodies, alkaloids, and a variety of other toxins. It plays an important role and has various functions.
  • It is important for the production of amino acids and proteins.
  • Pyrimidine and its derivatives are important in providing vital nutrients and contributing to an organism’s health.
  • It also helps to boost the immune system or antagonize and destroy cells.
  • Tetrodotoxin is a pyrimidine derivative found in many species like Japanese puffer fish and the blue ring octopus, which they use for self-protection. These toxins prevent the transmission of nerve signals and can result in paralysis or death.
  • It also plays a vital role in the development of drugs.
  • A wide range of pharmaceuticals has been using pyrimidine in general anesthetics, anti-malarial medication, anti-epilepsy medication, drugs for the treatment of high blood pressure, and HIV medication.

Structure of Nitrogen Bases

  • There are three pyrimidine nitrogen bases that are thymine (T), cytosine (C), and uracil (U).
  • They are six-membered ring that consists of four carbon atoms and two nitrogen atoms along with hydrogen atoms.
  • They all have a ketone (carbonyl group) on the second carbon (carbon atom that is present between the two nitrogen atoms instead of having an alternating double and single bond.
  • The three nitrogen bases, along with the carbonyl group, also have a functional group in the 4’ carbon region (a ketone for T and U and an amino group for C). similarly, T has a methyl group attached to its 5’ carbon atom.
  • In both the DNA and RNA, a number of modified pyrimidines can be found.
  • These nucleotides can be modified through oxidation, methylation, amination, or other forms by the addition of functional groups like aldehyde, thioketones, and alcohol.
  • These modifications may lead to alterations in the expression of the genes.
  • Modifications are mostly seen in the RNA (small nuclear RNA (snRNA)) than that DNA.


  1. Vinita Sharma, Nitin Chitranshi, Ajay Kumar Agarwal, “Significance and Biological Importance of Pyrimidine in the Microbial World”, International Journal of Medicinal Chemistry, vol. 2014, Article ID 202784, 31 pages, 2014.

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