Electrophilic pyrimidines. Medical search. Frequent questions

Therefore, electrophilic aromatic substitution is more difficult while nucleophilic aromatic substitution is facilitated. (wikipedia.org)
The MEP surface was studied to locate nucleophilic and electrophilic attack zones. (bvsalud.org)
Similar with pyridine, pyrazines are weakly aromatic and less prone to electrophilic substitution reaction, but easily reactive with nucleophilic reagent. (chemicalbook.com)
A novel series of azoles and azines were designed and prepared via reaction of 1,3-diphenyl-1 H -pyrazol-5(4 H )-one with some electrophilic and nucleophilic reagents. (biomedcentral.com)

The pKa value for protonated pyrimidine is 1.23 compared to 5.30 for pyridine. (wikipedia.org)
250 The 2-, 4-, and 6- positions on the pyrimidine ring are electron deficient analogous to those in pyridine and nitro- and dinitrobenzene. (wikipedia.org)
A novel method is by reaction of N-vinyl and N-aryl amides with carbonitriles under electrophilic activation of the amide with 2-chloro-pyridine and trifluoromethanesulfonic anhydride: Because of the decreased basicity compared to pyridine, electrophilic substitution of pyrimidine is less facile. (wikipedia.org)
1. Electrophilic substitution reaction of pyridine is most effective in which of the conditions? (sanfoundry.com)

In nucleic acids, three types of nucleobases are pyrimidine derivatives: cytosine (C), thymine (T), and uracil (U). The pyrimidine ring system has wide occurrence in nature as substituted and ring fused compounds and derivatives, including the nucleotides cytosine, thymine and uracil, thiamine (vitamin B1) and alloxan. (wikipedia.org)
Although pyrimidine derivatives such as alloxan were known in the early 19th century, a laboratory synthesis of a pyrimidine was not carried out until 1879, when Grimaux reported the preparation of barbituric acid from urea and malonic acid in the presence of phosphorus oxychloride. (wikipedia.org)
The systematic study of pyrimidines began in 1884 with Pinner, who synthesized derivatives by condensing ethyl acetoacetate with amidines. (wikipedia.org)
Pyrimidine biosynthesis creates derivatives -like orotate, thymine, cytosine, and uracil- de novo from carbamoyl phosphate and aspartate. (wikipedia.org)
As is often the case with parent heterocyclic ring systems, the synthesis of pyrimidine is not that common and is usually performed by removing functional groups from derivatives. (wikipedia.org)
For example, pyrimidine ring turns into purine derivatives after condensation. (lookchem.com)

electrophilic substitution reaction is easier than benzene, and it is mainly substituted at the 2-position. (chemenu.com)

Cu/Zn-superoxide dismutase (SOD)-accelerated oxidation of the benzene metabolite 1,4-hydroquinone (HQ) results in the enhanced formation of semiquinone anion radicals, electrophilic 1,4-benzoquinone (BQ), and H202. (shengsci.com)
In this chapter, electrophilic agents nogenicity from studies of exposed (benzene, 1,3-butadiene, and eth- include direct-acting electrophilic humans. (who.int)

So, next time when you hear about the genetic code, remember, it's all about how the purines and pyrimidines line up! (hellovaia.com)
It's this nitrogenous base where purines and pyrimidines enter the picture. (hellovaia.com)

Professor Schmidt said: "Arenediazonium salts are still underexplored and underrated electrophilic coupling reagents in Pd-catalyzed C-C bond forming reactions. (thieme.de)

437-439 Like pyridines, in pyrimidines the π-electron density is decreased to an even greater extent. (wikipedia.org)

Note that in DNA and RNA structures, the purine bases (adenine and guanine) are always paired with specific pyrimidine bases (thymine, cytosine, and uracil). (hellovaia.com)

Pyrimidine also photolytically decomposes into uracil under ultraviolet light. (wikipedia.org)

Protonation and other electrophilic additions will occur at only one nitrogen due to further deactivation by the second nitrogen. (wikipedia.org)
Kinetic and product studies of the reaction of 7-substituted 4-hydroxy-1,4-benzoxazin-3-ones in strongly acidic media produced biphasic Hammett plots which indicated the intermediacy of a highly electrophilic nitrogen compound with nitrenium ion character. (heterocycles.jp)

241-242 As a class, pyrimidines are typically synthesized by the principal synthesis involving cyclization of β-dicarbonyl compounds with N-C-N compounds. (wikipedia.org)

4-8 Reduction in resonance stabilization of pyrimidines may lead to addition and ring cleavage reactions rather than substitutions. (wikipedia.org)
149-239 Pyrimidines can be prepared via the Biginelli reaction and other multicomponent reactions. (wikipedia.org)

Pyrimidine is also found in meteorites, but scientists still do not know its origin. (wikipedia.org)
To give more context, in the world of genetics, these bases pair with specific pyrimidine bases found in DNA and RNA . (hellovaia.com)

Common among these 10 interactions of organic compounds, their power to detect excess cancer agents is the electrophilic nature of or their metabolites, with DNA and R 1 risk at particular sites. (who.int)

Therefore, electrophilic aromatic substitution is more difficult while nucleophilic aromatic substitution is facilitated. (wikipedia.org)
However, electrophilic substitution is relatively facile at the 5-position, including nitration and halogenation. (wikipedia.org)
A novel method is by reaction of N-vinyl and N-aryl amides with carbonitriles under electrophilic activation of the amide with 2-chloro-pyridine and trifluoromethanesulfonic anhydride: Because of the decreased basicity compared to pyridine, electrophilic substitution of pyrimidine is less facile. (wikipedia.org)
Kidder and Virginia [ 4 ] have noticed that the biological activity of pyrimidine changes with substitution. (rroij.com)

The activation of the carcinogen to an electrophilic DNA-damaging moiety is a necessary step for this stage. (studypurpose.com)
In S. cerevisiae, 19 thi genes are involved in the synthesis of TPP and the utilization of thiamin and thi20/21 participating in the synthesis of the pyrimidine moiety belong to multigene families. (ferienwohnung-gluecksburg.net)
2. Radiomodulatory effect of a non-electrophilic NQO1 inducer identified in a screen of new 6, 8-diiodoquinazolin-4(3H)-ones carrying a sulfonamide moiety. (nih.gov)

Pyrimidine biosynthesis creates derivatives -like orotate, thymine, cytosine, and uracil- de novo from carbamoyl phosphate and aspartate. (wikipedia.org)
At the mitochondrial level, atovaquone, targeting the cytochrome bc 1 complex, inhibits the parasite electron transport chain and thus the dihydro-orotate dehydrogenase (DHODH) activity linked to the respiratory chain and involved in pyrimidine nucleotide biosynthesis [ 8 ]. (biomedcentral.com)

Common among these 10 interactions of organic compounds, their power to detect excess cancer agents is the electrophilic nature of or their metabolites, with DNA and R 1 risk at particular sites. (who.int)