pyrimidine


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.

pyrimidine

(pīrĭm`ĭdēn'), type of organic base found in certain coenzymescoenzyme
, any one of a group of relatively small organic molecules required for the catalytic function of certain enzymes. A coenzyme may either be attached by covalent bonds to a particular enzyme or exist freely in solution, but in either case it participates intimately in
..... Click the link for more information.
 and in the nucleic acidsnucleic acid,
any of a group of organic substances found in the chromosomes of living cells and viruses that play a central role in the storage and replication of hereditary information and in the expression of this information through protein synthesis.
..... Click the link for more information.
 of plant and animal tissue. The three major pyrimidines of almost universal distribution in living systems are cytosinecytosine
, organic base of the pyrimidine family. It was isolated from the nucleic acid of calf thymus tissue in 1894. A suggested structure for cytosine, published in 1903, was confirmed in the same year when that base was synthesized in the laboratory.
..... Click the link for more information.
, thyminethymine
, organic base of the pyrimidine family. Thymine was the first pyrimidine to be purified from a natural source, having been isolated from calf thymus and beef spleen in 1893–4.
..... Click the link for more information.
, and uraciluracil
, organic base of the pyrimidine family. It was isolated from herring sperm and also produced in a laboratory in 1900–1901. When combined with the sugar ribose in a glycosidic linkage, uracil forms a derivative called uridine (a nucleoside), which in turn can be
..... Click the link for more information.
.

Pyrimidine

A heterocyclic organic

(2)
compound ( 1 ) containing nitrogen atoms at positions 1 and 3. Naturally occurring derivatives of the parent compound are of considerable biological importance as components of nucleic acids and coenzymes and, in addition, synthetic members of this group have found use as pharmaceuticals. See Coenzyme, Nucleic acid

Pyrimidine compounds which are found universally in living organisms include uracil ( 2 ), cytosine ( 3 ), and thymine

enlarge picture
(3)
( 4 ). Together with purines these substances make up the “bases” of nucleic acids, uracil and cytosine being found characteristically in ribonucleic acids, with thymine replacing uracil in deoxyribonucleic acids. A number of related pyrimidines also occur in lesser amounts in certain nucleic acids. Other pyrimidines of general natural occurrence are orotic acid and thiamine (vitamin B1). See Deoxyribonucleic acid (DNA), Purine, Ribonucleic acid (RNA)

Among the sulfa drugs, the pyrimidine derivatives, sulfadi-azine, sulfamerazine, and sulfamethazine, have general formula ( 5 ).

enlarge picture
(4)
These agents are inhibitors of folic acid biosynthesis in microorganisms. The barbiturates are pyrimidine derivatives which possess potent depressant action on the central nervous system.

Pyrimidine

 

(also called 1,3-diazine), a heterocyclic compound. Colorless crystals; melting point, 21°C; boiling point, 124°C. Pyrimidine is readily soluble in water, alcohol, and ether. The structural formula is

Pyrimidine is a very weak, monoacidic base that forms quaternary salts, each of which contains a single nitrogen atom; it also reacts with hydrogen peroxide (H2O2) to yield N-oxides. Pyrimidine does not enter readily into electrophilic substitution reactions, for example, halogenation, sulfonation, and nitration, but the hydrogen atom on the carbon in position number four is easily replaced in reactions with organomagnesium compounds, organolithium compounds, NaNH2, and KOH. Pyrimidine is synthesized by reduction of its 2,4,6-trichloro derivative, which is a product of the reaction of POCI3 with barbituric acid. Pyrimidine and its derivatives are components of individual nucleotides and of nucleic acids, the most important biopolymers. They also occur in many biologically active substances, including thiamine, the antibiotic, amicetin, and barbiturates.

pyrimidine

[pə′rim·ə‚dēn]
(biochemistry)
C4H4N2 A heterocyclic organic compound containing nitrogen atoms at positions 1 and 3; naturally occurring derivatives are components of nucleic acids and coenzymes.
References in periodicals archive ?
Mintas, Synthesis and antitumor activities of novel pyrimidine derivatives of 2,3-o,o-dibenzyl-6-deoxy-l-ascorbic acid and 4,5-didehydro-5,6-dideoxy-l-ascorbic acid, J.
This rotation creates a similar chemical environment for the protons closer to the pyrimidine [H.sub.8e] and [H.sub.8i].
This is possibly due to the presence of extra pyrimidine moiety with azo system at the end of acceptor in the Chromophore c, which hinders the degree of free-rotation and thus, plays an important role in enhancing the thermal stability of the polyurethanes.
Given the enrichment of gene sets associated with nucleotide metabolism in both datasets, we examined the specific effects on short-term IFN-[alpha] stimulation on purine and pyrimidine metabolism.
Dobritzsch, "Amidohydrolases of the reductive pyrimidine catabolic pathway purification, characterization, structure, reaction mechanisms and enzyme deficiency," Biochimica et Biophysica Acta, vol.
Decitabine is an azanucleoside (AZN), a pyrimidine analogue of cytidine.
We studied the action of hydrazine hydrate as N-nucleophile on Biginelli pyrimidine esters 4a-4h.
The concentrations of cytosine, total nucleic acid bases and pyrimidine bases were significantly affected by the interaction of lactation stages and time of sampling.
It is important to remember that compound 1 is able to coordinate in both arms through four atoms, three nitrogen atoms of the pyridine-imine and pyrimidine framework and a fourth one from the carboxylic group, thus the four sites of coordination prefer to generate a more stable tetrahedral complex around the ion (Z[n.sup.2+] or C[d.sup.2+]) than a complex of coordination 8 that would have in a grid-type complex.
In this study, the biosynthetic pathways of purine and pyrimidine nucleosides in H.
The remaining 38 agents can be classified into the following categories: anticoagulant (2), antidiarrheal (1), antidiabetic (1), antidote (3), antiemetic (1), antifungal (1), antilipemic (2), antineoplastic (13), antipsychotic (2), antiviral (1), bile acid (2), cardiovascular (2), female sexual dysfunction (1), immunomodulator (1), lysosomal acid lipase deficiency (1), parathyroid hormone (1), pyrimidine analog (1), and respiratory (2).
Results of quantitaion of Purine and Pyrimidine bases using Ethyl Chloroformate as Derivatizing Reagent.