نتایج جستجو برای: 3 dimethyl uracil
تعداد نتایج: 1831853 فیلتر نتایج به سال:
Three known compounds including, uracil (1), 5-methyl (2) and uridine (3) have been isolated from the soft coral Litophyton arboreum collected red sea. The were identified using spectroscopic techniques predominately 1H-NMR 13C-NMR analyses, in addition to HR-ESI-MS. Moreover, 1-3 vitro estimated for their cytotoxic activity against three human cancer cell lines (A549, MCF-7 HepG2), antileishma...
N-1 regioselective Michael-type addition of 5-substituted uracils to (2-hydroxyethyl) acrylate is presented. The reactions were performed in polar aprotic solvents and with avoidance of polymerization of acrylic substrate. The obtained adducts may serve as versatile substrates for further functionalization, e.g. into (3-uracil-1-yl)propanoic acids or transformations, with participation of hydro...
Same as Report (SAR) 18. NUMBER
The excited state properties of uracil, thymine and four analogous uracil compounds have been studied in acetonitrile by steady-state and time-resolved spectroscopy. The excited state lifetimes were measured using femtosecond UV fluorescence upconversion. The excited state lifetimes of uracil and its 1and 3-methyl substituted derivatives are well described by one ultrafast (6100 fs) component. ...
We isolated mutations in Arabidopsis to understand how the female gametophyte controls embryo and endosperm development. For the DEMETER (DME) gene, seed viability depends only on the maternal allele. DME encodes a large protein with DNA glycosylase and nuclear localization domains. DME is expressed primarily in the central cell of the female gametophyte, the progenitor of the endosperm. DME is...
Archaeal family-B DNA polymerases possess a novel uracil-sensing mechanism. A specialized pocket scans the template, ahead of the replication fork, for the presence of uracil; on encountering this base, DNA synthesis is stalled. The structural basis for uracil recognition by polymerases is described and compared with other uracil-recognizing enzymes (uridine-triphosphate pyrophophatases and ura...
MEDEA (MEA) is an Arabidopsis Polycomb group gene that is imprinted in the endosperm. The maternal allele is expressed and the paternal allele is silent. MEA is controlled by DEMETER (DME), a DNA glycosylase required to activate MEA expression, and METHYLTRANSFERASE I (MET1), which maintains CG methylation at the MEA locus. Here we show that DME is responsible for endosperm maternal-allele-spec...
Most of the literature dealing with the participation of citrovorum factor and vitamin Blz in the formation and transfer of l-carbon intermediates stresses the donor compounds serine, glycine, and formate as precursors of the 5-methyl group of thymidine (2). Uracil deoxyriboside, first isolated in crystalline form by Dekker and Todd (3) in 1950, is known to arise as a result of the deamination ...
The Mannich reaction of 7-aryl-5,6-dihydropyrido[2,3-d]pyrimidines 3, easily accessible by condensation of 6-amino-1,3-dimethyluracil (1) with Mannich bases 2a – c, gives rise to a mixture of 7-aryl-6-(N,N-dimethylaminomethyl)pyrido[2,3-d]pyrimidines 6 and 7 as well as 1,2-bis(7-arylpyrido[2,3-d]pyrimidin-6-yl)ethane 13 the ratio of which depends on the reaction conditions and the amine used. 6...
1. When DNA is hydrolysed with formic acid for 30min. at 175 degrees and the hydrolysate is chromatographed on paper with propan-2-ol-2n-hydrochloric acid, in addition to expected ultraviolet-absorbing spots corresponding to guanine, adenine, cytosine and thymine, an ultraviolet-absorbing region with R(F) similar to that of uracil can be detected. Uracil was separated from this region and ident...
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