Full Text Available The synthesis was performed using 5-methyluracil mono-and bis-derivatives with the halogen-containing pharmacophore groups in the composition of molecules; their physiochemical and biological properties were studied. These reactions are a typical example of substitution reactions on heteroatom N(1 of uracil molecule using as the second component the reaction of halothane—the known inhaled anesthetic. The reactions were carried out in a solvent system: benzene-dimethyl formamide and diethyl ether, under conditions of phase transfer catalysis DB-18-crown-6-complex (alkaline medium, by heating from 2 to 11 hours, followed by purification, and drying of the resulting products. The structure of the synthesized compounds was confirmed by elemental analysis, IR and 1HNMR spectra. The purity was controlled by the methods of thin-layer and gas-liquid chromatography. Chromatography, IR and 1HNMR spectra of the final products were identified in comparison with the chromatograms, IR and 1HNMR spectra of the initial compounds. Variation of the reaction conditions and changes in methods of synthesis enabled to receive the synthesized compounds of high purity and to increase their practical output up to 43-80%. Molecular complex of Bacterial lectin and 5-methyluracil bis-derivative was obtained. The toxicity and anti-tumor activity of some of the synthesized compounds were investigated. We have found that the new molecular complex of Bacterial lectin and 5-methyluracil bis-derivative has high anti-tumor activity in Limphosarcoma Plissa—62.8% (activity criterion >50%, which allows us to consider the synthesized compound as a physiologically active compound with the prospect for further study as a potential vehicle for anti-tumoral treatment in patients.
Simultaneous determination of 1-(2'-deoxy-2'-fluoro-β-D-arabinofuranosyl) uracil (FAU) and 1-(2'-deoxy-2'-fluoro-β-D-arabinofuranosyl) 5-methyluracil (FMAU) in human plasma by liquid chromatography/tandem mass spectrometry.
Wiegand, Richard; Wu, Jianmei; Shields, Anthony F; Lorusso, Patricia; Li, Jing
A liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) assay was developed and validated for simultaneous determination of 1-(2'-deoxy-2'-fluoro-β-D-arabinofuranosyl) uracil (FAU) and its active metabolite 1-(2'-deoxy-2'-fluoro-β-D-arabinofuranosyl) 5-methyluracil (FMAU) in human plasma. FAU and FMAU were extracted from plasma samples using solid-phase extraction with Waters Sep-Pak® Vac C₁₈ cartridge. Chromatographic separation was achieved on a Waters Atlantis T3 C₁₈ column with a gradient mobile phase consisting of methanol and water with 0.45% formic acid (v/v) running at a flow rate of 0.2 ml/min. The analytes were monitored by triple quadrupole mass spectrometer under positive ionization mode. The lower limit of quantitation (LLOQ) was 10 and 2 ng/ml for FAU and FMAU in plasma, respectively. Calibration curves were linear over FAU and FMAU plasma concentration range of 10-2000 and 2-1000 ng/ml, respectively. The intra-day and inter-day accuracy and precision were within the generally accepted criteria for bioanalytical method (FAU and FMAU in cancer patients receiving 1-h intravenous infusion of FAU 50 mg/m².
孙武兴; 李铣; 李宁; 孟大利
目的 分离、鉴定毛金竹(Phyllostachys nigra(Lodd.exLindl.)Munro var.henonis(Mitf.)Stepf ex Rendle)竹叶提取物的化学成分.方法 采用反复硅胶柱色谱、Sephdex LH-20柱色谱、开放ODS柱色谱、制备薄层色谱等方法进行分离纯化,并通过理化性质和光谱数据鉴定其化学结构.结果 从其乙酸乙酯萃取层和正丁醇萃取层分离得到12个化合物,分别鉴定为β-谷甾醇(β-sitosterol,1)、苜蓿素(tricin,2)、胡萝卜苷(daucosterol,3)、丁二酸(butanedioic acid,4)、胸腺嘧啶(5-methyluracil,5)、苜蓿素-7-O-β-D-葡萄糖苷(tricin-7-O-β-D-glucopyranoside,6)、牡荆苷(vitexin,7)、苜蓿素-7-O-新橙皮糖苷(tricin-7-O-neohesperidoside,8)、荭草苷(orientin,9)、异荭草苷(isoorientin,10)、尿嘧啶(uracil,11)、胸腺嘧啶脱氧核苷(thymidine,12).结论 化合物4～6、8、11、12为首次从该属植物中分离得到.
Hashimoto, Hideharu; Wang, Dongxue; Steves, Alyse N.; Jin, Peng; Blumenthal, Robert M.; Zhang, Xing; Cheng, Xiaodong
Reprogramming of mammalian genome methylation is critically important but poorly understood. Klf4, a transcription factor directing reprogramming, contains a DNA binding domain with three consecutive C2H2 zinc fingers. Klf4 recognizes CpG or TpG within a specific sequence. Mouse Klf4 DNA binding domain has roughly equal affinity for methylated CpG or TpG, and slightly lower affinity for unmodified CpG. The structural basis for this key preference is unclear, though the side chain of Glu446 is known to contact the methyl group of 5-methylcytosine (5mC) or thymine (5-methyluracil). We examined the role of Glu446 by mutagenesis. Substituting Glu446 with aspartate (E446D) resulted in preference for unmodified cytosine, due to decreased affinity for 5mC. In contrast, substituting Glu446 with proline (E446P) increased affinity for 5mC by two orders of magnitude. Structural analysis revealed hydrophobic interaction between the proline's aliphatic cyclic structure and the 5-methyl group of the pyrimidine (5mC or T). As in wild-type Klf4 (E446), the proline at position 446 does not interact directly with either the 5mC N4 nitrogen or the thymine O4 oxygen. In contrast, the unmethylated cytosine's exocyclic N4 amino group (NH2) and its ring carbon C5 atom hydrogen bond directly with the aspartate carboxylate of the E446D variant. Both of these interactions would provide a preference for cytosine over thymine, and the latter one could explain the E446D preference for unmethylated cytosine. Finally, we evaluated the ability of these Klf4 mutants to regulate transcription of methylated and unmethylated promoters in a luciferase reporter assay.
Hua, XinZhong; Hua, LinQiang; Liu, XiaoJun
The nonradiative decay dynamics of photo-excited uracil (Ura) and its derivatives, i.e., thymine (5-methyluracil, Thy), 6-methyluracil (6-MU) and 6-azauracil (6-AU) in water, has been studied using a femtosecond transient absorption method. The molecules are populated in the lowest (1)ππ* state by a pump pulse at 266 nm, and a broadband continuum in the deep UV region is then employed as the probe. The extension of the continuous UV probe down to 250 nm enables us to investigate comprehensively the population dynamics of the ground states for those molecules and to uncover the substituent effects on nonradiative decay dynamics of uracil. Vibrational cooling in the ground states of Ura, Thy and 6-MU has been directly observed for the first time, providing solid evidence of the ultrafast (1)ππ* → S0 decay. In combination with the ground state bleaching signals, it is consolidated that their lowest (1)ππ* state decays via two parallel pathways, i.e., (1)ππ* → S0 and (1)ππ* → (1)nπ*. Moreover, the contribution of the (1)ππ* → (1)nπ* channel is found to be much smaller for Thy or 6-MU than for Ura. Different from methyl-substitution, the initial (1)ππ* state of the aza-substituent 6-AU decays primarily to the (1)nπ* state, while the (1)ππ* → S0 channel can be negligible. Our study provides a comprehensive understanding of the substituent effects on the excited-state dynamics of uracil in water.