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101.
由2-氰-5-氟-3H-4-嘧啶酮和取代苯酚钠在常压下反应,合成了7个未见文献报道的2-芳氧基-5-氟-3H-4-嘧啶酮化合物,产率70 ̄87%,结构经IR、^1H NMR和MS证实。 相似文献
102.
Fei Ye Xiaoyan Qiao Anhui Gui Shengpeng Wang Panpan Liu Xueping Wang Jin Teng Lin Zheng Lin Feng Hanshan Han Shiwei Gao Pengcheng Zheng 《Molecules (Basel, Switzerland)》2021,26(21)
This study aimed to compare the effect of hot roller (HR) drying and hot air (HA) drying on the sensory evaluation, chemical quality, antioxidant activity, and metabolic profile of Yihong Congou black tea processed from E’cha NO1. The Yihong Congou black tea dried with HA obtained higher sensory scores and better chemical qualities such as the hue of tea brew color (a and b), content of theaflavins, thearubigins, water extract, free amino acids, tea polyphenol, and the ratio of polyphenol to amino acids as well as higher antioxidant capacities compared to that dried with HR. The HA drying tea increased the contents of volatile compounds that had positive correlation with sweet and flowery flavor, while the HR drying tea increased the contents of volatile compounds related to fruity flavor. Moreover, non-targeted metabolomics data indicated that the levels of most free amino acids significantly increased, while the levels of most soluble sugars reduced in the HA drying method compared to the HR drying method. The metabolic analysis was also consistent with the above results and revealed that D-ribose and gallic acid were the main characteristic metabolites of HA drying. Our results could provide a technical reference and theoretical guide to processing a high quality of Yihong Congou black tea. 相似文献
103.
硝基酚类化合物在海水中的光化学氧化研究 总被引:11,自引:0,他引:11
酚类化合物尤其是硝基苯酚属于国家严格控制排放的有毒物质 .由于工业排污等原因 ,在近岸水体中能检测到许多酚类化合物 .我国胶州湾和杭州湾表层海水中酚的含量分别高达 3和 9mg/L[1] .酚的毒性会影响海水生物的生长和繁殖 ,危及人类健康 .由于硝基苯酚难于生化降解 ,因此研究其在水体中的光降解十分重要 [2~ 6 ] .文献中关于有机污染物的光化学研究大多侧重于废水处理 ,且降解方法也多采用 Ti O2 催化降解 [7,8] .对于硝基苯酚在天然水体中的光降解则知之甚少 .本文通过模拟海水条件下硝基苯酚的光化学反应及其影响因素 ,更加深入地了… 相似文献
104.
A modified poly(ethylene glycol) (PEG) has been developed as the soluble polymeric supports for liquid phase synthesis of novel thiourea derivatives.In each step of the sequence,the PEG-bound products were precipitated in cold Et2O and the unreacted materials and by-products were removed by simple filtration.The progress of reaction,purity of the isolation and the structure of the PEG-bound products were easily monitored by TLC,IR and ^1H NMR spectra.Representative thiourea derivatives were obtained in moderate yields with excellent purity from this modified PEG-bound product by the cleavage with 50% TFA/H2O. 相似文献
105.
106.
Kai Jun LUO Ming Gui XIE* Qing JIANG Testing Center of Sichuan Normal University Chengdu Research institute of Molecular Function Material Sichuan University Chengdu 《中国化学快报》2003,14(11)
Circularly polarized luminescent(CPL) materials possess special dissymmetric optical property, i.e. luminescent light having different intensities for left (L) and right(R) circularly polarized components. Recently, these materials have been applied in colour-image projection, stereoscopic displays and light-emitting diodes(LEDS)1-7. We have synthesized a new porphyrin derivative, tetra-4[4'-(2-methylbutoxy)benzoyloxy] phenyl porphyrin [T(MBBP)P], by introducing a chiral group, which p… 相似文献
107.
Coating Carbon Nanotubes with Europium Oxide 总被引:4,自引:0,他引:4
HuiQunCAO GuangYanHONG JingHuiYAN JiLinZHANG GuiXiaLIU 《中国化学快报》2003,14(12):1293-1295
Carbon nanotubes (CNTS) coating with europium oxide by a simple method is reported in this letter for the first time. The CNTS were refluxed in a solution of nitric acid containing europium nitrate, and the pH value was subsequently ajusted with ammonia solution. At last, the mixture was filtered and annealed. The TEM micrograph showed that the CNTS were covered with a uniform thin layer with thickness of about 15 nm. The XRD results revealed that the CNTS were coated with europium oxide. 相似文献
108.
酸性品红与蛋白质结合反应的研究及应用 总被引:2,自引:0,他引:2
在pH1.4的Clark-Lubs缓冲介质中,蛋白质与酸性品红反应形成结合物,该结合物的最大吸收波长为576nm,与酸性品红相比,红移了34nm。据此拟定了分析方法,制定了牛血清白蛋白(BSA)、人血清白蛋白(HAS)、γ-球蛋白(γ-G)和酪蛋白的工作曲线,测定的摩尔吸光系数均在10^5数量级,用于人血清中总蛋白的测定,结果与溴甲酚绿(BCG)法基本一致。 相似文献
109.
110.
Ming‐Sheng Xie Ye‐Fei Zhang Meng Shan Xiao‐Xia Wu Gui‐Rong Qu Hai‐Ming Guo 《Angewandte Chemie (International ed. in English)》2019,58(9):2839-2843
A DMAP‐N‐oxide, featuring an α‐amino acid as the chiral source, was developed, synthesized and applied in asymmetric Steglich rearrangement. A series of O‐acylated azlactones afforded C‐acylated azlactones possessing a quaternary stereocenter in high yields (up to 97 % yield) and excellent enantioselectivities (up to 97 % ee). Compared to the widespread use of pyridine nitrogen, which serves as the nucleophilic site in the asymmetric acyl transfer reaction, we discovered that chiral DMAP‐N‐oxides, in which the oxygen now acts as the nucleophilic site, are efficient acyl transfer catalysts. Our finding might open a new door for the development of chiral DMAP‐N‐oxides for asymmetric acyl transfer reactions. 相似文献