Search results for "URACIL"
showing 10 items of 343 documents
Synthesis and antiproliferative activity of 2'-O-allyl-1-beta-D-arabynofuranosyl-uracil, -cytosine and -adenine
1997
Abstract With the aim to design potential inhibitors of ribonucleotide reductase (RR), 2′-O-allyl-β-D-arabinofuranosyl-uracil ( 4 ), -cytosine ( 7 ) and -adenosine ( 10 ) were prepared and evaluated for their cytostatic activity against Molt4/C8, CEM and L1210 cell lines. Although our preliminary data do not allow to assess if RR is the intracellular target, the results point to differences in the (anti)metabolic behavior of these compounds. This study also offers a general synthesis of 2′-O-allyl-β-D-arabinofuranosyl nucleosides for potential applications in the preparation of 2′-O-allyl-β-D-oligoarabino nucleotides.
An efficient synthesis of uracil derivatives from 2-alkyl-Δ2-oxazolines and nitriles
2008
An efficient and convenient synthesis of new fluorinated and non-fluorinated uracils is described herein. The condensation of nitriles with enolates generated from 2-alkyl-Δ 2 -oxazolines (I) affords fluorinated β-enamino acid derivatives, which react with triphosgene to give an isomeric mixture of oxazolopyrimidinones. These can then be easily transformed into a single C-6 pyrimidindione derivative through reaction with a suitable nucleophile.
Eine quantitative Bestimmungsmethode des Uracilgehaltes biologischen Materials im Nanogramm-Bereich mit Hilfe der Hochdruck-Flüssigchromatografie / A…
1974
Abstract A method is described for the estimation of the uracil content in biological materials by means of high-pressure liquid chromatography. Hydrolysis of the tissues and total liberation of RNA bases are carried out in 70% perchloric acid. Less than 1 mg of the materials are needed for analysis. A pre-purification of the hydrolyzates is carried out by anion-exchange chromatography. Recoveries are estimated by isotope dilution analysis with [2-14C] labelled uracil. The method is highly sensitive - about 6000 pmol of uracil content can at least be estimated quantitatively - and analysis time is short. In routine analysis a single sample needs 4 hours to be completed. When preparing sever…
An efficient synthesis of new fluorinated uracil derivativesElectronic supplementary information (ESI) available: general procedures for the preparat…
2003
A series of potentially biologically active fluorinated uracil derivatives has been prepared in three steps from oxazolines and fluorinated nitriles with good chemical yields.
Cyclobutane Pyrimidine Photodimerization of DNA/RNA Nucleobases in the Triplet State
2010
The photoinduced formation of cyclobutane pyrimidine dimers in the triplet excited state of the DNA/RNA pyrimidine nucleobases pairs has been studied at the CASPT2 level of theory. A stepwise mechanism through the triplet state of the homodimer is proposed for the pairs of nucleobases cytosine, thymine, and uracil involving a singlet−triplet crossing intermediary structure of biradical character representing the most favorable triplet state conformation of the nucleobases as found in the DNA environment. The efficiency of the mechanism will be modulated by two factors: the effectiveness of the triplet−triplet energy transfer process from a donor photosensitizer molecule, which relates to th…
Bleomycin, a selective inhibitor of DNA-dependent DNA polymerase from oncogenic RNA viruses.
1972
Abstract Bleomycin, an antibiotic, inhibits the DNA-dependent DNA polymerase from Rauscher murine leukemia virus. Higher concentrations of BLM ∗ are required to inhibit it's RNA-dependent DNA polymerase. These inhibition effects of the non-competitive type are not altered by preincubation of the DNA with BLM. Under comparable conditions neither the DNA-dependent DNA polymerase activity from E. coli and mouse liver nor the DNA-dependent RNA polymerase activity from mouse lymphoma cells are affected by BLM.
Tworzenie kompleksów inkluzyjnych pomiędzy 5-fluorouracylem a β-cyklodekstrynami
2017
Celem przedstawionego opracowania jest omówienie najważniejszych zagadnień dotyczących chemioterapii z użyciem 5-fluorouracylu, jego metabolizmu oraz zagrożenia wynikające z leczenia tym chemioterapeutykiem. Poruszona została również kwestia możliwości ograniczenia toksyczności 5FU, przez zainkludowaniu go we wnętrzu molekuły β-cyklodekstryny. Przedstawiono również najważniejsze wyniki badań teoretycznych w których przedstawiono geometrię kompleksu inkluzyjnego 5FU⎼βCD. Struktura została zoptymalizowana na poziomie teorii funkcjonału gęstości (DFT) z użyciem metody B3LYP/6-31G. Wykazano istnienie przynajmniej jednego wiązania wodorowego pomiędzy grupą aminową 5FU, a grupą hydroksylową powie…
Bioaccesibility of Cylindrospermopsin from cooked fish muscle after the application of an in vitro digestion model and its bioavailability.
2017
Humans can be exposed to cyanotoxins through the ingestion of contaminated water, food or beverages. In the present work, the bioaccesibility of Cylindrospermopsin (CYN), one of the most relevant cyanotoxins, was evaluated in a pure CYN solution and cooked CYN-contaminated fish muscles (20 μg/mL). An in vitro digestion model including the salivar, gastric, duodenal and colonic phases was performed, being each fraction analyzed by HPLC-MS-MS to evaluate CYN degradation. Moreover, Caco-2/TC7 cells were exposed to the digested duodenal and colonic phases to elucidate the final bioavailability of CYN in an approximation to the real human exposure scenario. The results revealed that CYN bioacces…
Temperature effects explain continental scale distribution of cyanobacterial toxins
2018
Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect…
A phase I-II study of cyclophosphamide, epidoxorubicin, levofolinic acid/5-fluorouracil and recombinant human granulocyte colony stimulating factor i…
1994
Thirty patients with measurable metastatic breast carcinoma were treated with a combination of cyclophosphamide 600 mg/m2 on day 1, levofolinic acid 100 mg/m2 plus 5-fluorouracil 375 mg/m2 on days 1-3, and epidoxorubicin (EDXR) in three refracted doses on days 1-3 with G-CSF rescue for 10 days. In the phase I part of the study, groups of 3 patients received EDXR 20, 25, 30, 35, and 40 mg/m2/day until the dose limiting toxicity (DLT) was reached. At the dose of 40mg/m2/day prolonged grade 4 leukopenia, severe proctitis, and grade 3 diarrhea represented the DLT. All subsequent partients were treated at the maximal tolerated dose of EDXR (35 mg/m2/day). In the group of 18 patients treated at 3…