期刊文献+
共找到534篇文章
< 1 2 27 >
每页显示 20 50 100
H3K27乙酰化修饰促进lncRNA OIP5-AS1转录并通过上调TLR4诱导过敏性鼻炎鼻黏膜上皮细胞凋亡
1
作者 谢勇 佘志强 +3 位作者 李容华 吴荣华 王瑢 刘继远 《细胞与分子免疫学杂志》 CAS CSCD 北大核心 2024年第5期419-427,共9页
目的本研究旨在探讨组蛋白3的27位赖氨酸(H3K27)乙酰化修饰对长链非编码RNA OPA相互作用蛋白5-反义RNA1(lncRNA OIP5-AS1)转录的促进作用,探讨其通过调控Toll样受体4(TLR4)对过敏性鼻炎(AR)中鼻黏膜上皮细胞(NEC)凋亡的影响。方法白细... 目的本研究旨在探讨组蛋白3的27位赖氨酸(H3K27)乙酰化修饰对长链非编码RNA OPA相互作用蛋白5-反义RNA1(lncRNA OIP5-AS1)转录的促进作用,探讨其通过调控Toll样受体4(TLR4)对过敏性鼻炎(AR)中鼻黏膜上皮细胞(NEC)凋亡的影响。方法白细胞介素13(IL-13)处理NEC以建立AR细胞模型。采用实时定量PCR检测OIP5-AS1和TLR4在AR患者鼻黏膜组织和体外细胞模型中的表达。ELISA检测粒细胞-巨噬细胞集落刺激因子(GM-CSF)、嗜酸性粒细胞趋化因子1(eotaxin-1)和黏蛋白5AC(MUC5AC)的浓度。原位末端转移酶标记技术(TUNEL)染色法用于检测NEC的凋亡。双荧光素酶报告实验用于验证OIP5-AS1和TLR4的关系。染色质免疫沉淀(ChIP)实验分析用于验证OIP5-AS1启动子区组蛋白的H3K27乙酰化修饰。结果与健康对照和未处理的NEC相比,OIP5-AS1和TLR4在AR患者鼻黏膜组织和IL-13刺激的NEC中均表达升高。敲减OIP5-AS1可降低IL-13诱导的NEC的TLR4水平,而过表达OIP5-AS1可增加IL-13处理的NEC的TLR4水平。敲减OIP5-AS1可降低IL-13处理的NEC凋亡率及GM-CSF、eotaxin-1和MUC5AC的分泌,而过表达TLR4可部分逆转敲减OIP5-AS1对NEC凋亡及GM-CSF、eotaxin-1和MUC5AC表达的影响。此外,H3K27ac在OIP5-AS1的启动子区域显著富集,H3K27乙酰化可促进OIP5-AS1在IL-13诱导的NEC中的表达。结论H3K27乙酰化修饰促进OIP5-AS1转录并通过上调TLR4诱导AR中NEC凋亡。 展开更多
关键词 h3K27 OIP5-AS1 TLR4 鼻黏膜上皮细胞(NEC)
下载PDF
A rapid synthesis of isoxazolo[5,4-d]pyrimidin-4(5H)-ones under microwave irradiation with solid acid catalysis in solvent-free conditions 被引量:1
2
作者 A.Davoodnia M.Roshani +1 位作者 S.H.Malaeke M.Bakavoli 《Chinese Chemical Letters》 SCIE CAS CSCD 2008年第5期525-528,共4页
A rapid and efficient method for the synthesis of isoxazolo[5,4-d]pyrimidin-4(5H)-ones has been developed through cyclocondensation of 5-aminoisoxazole-4-carboxamides with orthoesters under conventional heating and ... A rapid and efficient method for the synthesis of isoxazolo[5,4-d]pyrimidin-4(5H)-ones has been developed through cyclocondensation of 5-aminoisoxazole-4-carboxamides with orthoesters under conventional heating and solvent-free microwave irradiation with solid acid catalysis. In comparison, the reactions are faster and the yields are higher under microwave irradiation. 展开更多
关键词 Isoxazolo[5 4-d]pyrimidin-45h)-ones ORThOESTERS Microwave irradiation Conventional heating
下载PDF
A Selective Synthesis of 2-Alkylamino-5, 6, 7, 8-tetrahydro-benzothieno[2, 3-d]pyrimidin-4(3H)-ones 被引量:1
3
作者 MingWuDING RuiJunXU JingXU YunFengCHEN 《Chinese Chemical Letters》 SCIE CAS CSCD 2005年第2期189-192,共4页
Alkylamino-5, 6, 7, 8-tetrahydrobenzothieno [2, 3-d] pyrimidin-4(3H)-ones 7 weresynthesized by a new selective synthetic method, which includes aza-Wittig reaction of imino-phosphorane 4 with aromatic isocynate to giv... Alkylamino-5, 6, 7, 8-tetrahydrobenzothieno [2, 3-d] pyrimidin-4(3H)-ones 7 weresynthesized by a new selective synthetic method, which includes aza-Wittig reaction of imino-phosphorane 4 with aromatic isocynate to give carbodiimide 5 and subsequent reaction of 5 withvarious aliphatic primary amine in the presence of EtO-Na+. 展开更多
关键词 Benzothieno[2 3-d]pyrimidin-4(3h)-ones aza-Wittig reaction iminophosphorane carbodiimide synthesis.
下载PDF
组蛋白去甲基化酶KDM5A调控H3K4me3参与神经管畸形发生的分子机制
4
作者 李建婷 解琪 +5 位作者 谷小龙 曹志华 彭志伟 赵虹 刘志贞 解军 《中国生物化学与分子生物学报》 CAS CSCD 北大核心 2024年第5期629-637,共9页
神经管畸形(NTDs)的病因与防治是出生缺陷领域研究的重点,叶酸可以预防神经管畸形但其机制不明。本文借助低叶酸细胞模型和低叶酸NTDs小鼠模型通过染色质免疫共沉淀、Cut&Tag等技术,探讨了组蛋白去甲基化酶lysine demethylase 5A(KD... 神经管畸形(NTDs)的病因与防治是出生缺陷领域研究的重点,叶酸可以预防神经管畸形但其机制不明。本文借助低叶酸细胞模型和低叶酸NTDs小鼠模型通过染色质免疫共沉淀、Cut&Tag等技术,探讨了组蛋白去甲基化酶lysine demethylase 5A(KDM5A)及其调控的下游组蛋白H3K4me3修饰在叶酸缺乏导致的NTDs发生中的潜在分子机制。结果显示,低叶酸的细胞模型中,qRT-PCR、Western印迹结果显示,KDM5A分子表达明显下降(P<0.05)。作为组蛋白H3K4me3调控的上游关键酶,进一步通过染色质免疫共沉淀ChIP、ChIP-qPCR实验证实,叶酸缺乏下组蛋白H3K4me3在神经发育基因Axin 2和Atoh 1基因启动子区富集增加(P<0.05)。通过构建KDM5A基因敲除细胞模型,借助Cut&Tag试验证实,KDM5A基因敲除后H3K4me3主要富集在神经发育基因上。最后在低叶酸导致的NTDs小鼠模型的脑组织中,RT-qPCR、Western印迹以及ChIP-qPCR实验显示,E9.5 d的NTDs胎鼠脑组织中KDM5A表达下降(P<0.05),Axin2、Atoh1表达升高(P<0.05),Axin2、Atoh 1基因启动子区的H3K4me3富集增多(P<0.05)。综上所述,KDM5A蛋白在叶酸缺乏导致的NTDs中发挥重要作用,其可通过调控下游H3K4me3进而调控神经发育靶基因Axin2、Atoh 1异常表达,介导NTDs的发生。本研究从叶酸缺乏介导KDM5A调控组蛋白修饰来探讨NTDs的发病机制,为降低出生缺陷,促进生殖健康提供依据。 展开更多
关键词 神经管畸形 叶酸 组蛋白去甲基化酶5A 组蛋白h3K4me3
下载PDF
Efficient Synthesis of 2-Substituted Quinolino[7',8':5,6]pyrano-[2,3-d]pyrimidin-4(3H)-ones via Tandem Aza-Wittig Reaction
5
作者 FANG Zheng-dong WANG Guo-hong WANG Dun-jia 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2009年第6期866-869,共4页
An efficient method is described for the synthesis of 2-substituted quinolino[7',8':5~6]pyrano[2,3-d] pyrimidin-4(3H)-ones(6) via a tandem aza-Wittig annulation process. The iminophosphorane(3) reacted with a... An efficient method is described for the synthesis of 2-substituted quinolino[7',8':5~6]pyrano[2,3-d] pyrimidin-4(3H)-ones(6) via a tandem aza-Wittig annulation process. The iminophosphorane(3) reacted with aromatic isocyanates, followed by heterocyclization on the addition of secondary amines, phenols or alcohols to give the corresponding guanidine intermediates(5), which were cyclized in the presence of a catalytic amount of a base to tetracyclic compounds 6 in good yields. The corresponding carbodiimide(4) and guanidine-type intermediate compounds 5 need not be isolated. 展开更多
关键词 Quinolinopyran Pyranopyrimidin-4(3h)-one Aza-Wittig reaction
下载PDF
Various Routes to Synthesise 3-Thioxo-1,2,4-Triazine-5-One Derivatives as Antimicrobial Agents
6
作者 Reda M. Abdel-Rahman Wafa A. Bawazir 《International Journal of Organic Chemistry》 2018年第2期191-200,共10页
A simple condensation afforded some new 3-thioxo-1,2,4-triazin-5-one derivatives (4, 6 and 8). Utilizing a facile condensation of (E)-4-(4’-bromo styryl)-2-oxo-3-buteneoic acid with thiosemicarbazide, dithioic formic... A simple condensation afforded some new 3-thioxo-1,2,4-triazin-5-one derivatives (4, 6 and 8). Utilizing a facile condensation of (E)-4-(4’-bromo styryl)-2-oxo-3-buteneoic acid with thiosemicarbazide, dithioic formic acid hydrazide, and thiocarbahydrazide in different conditions. Structures of these compounds were confirmed by elemental and spectral analysis. The preliminary biocidal activity of these products were evaluated against some microbial and compared to Mycostatine and piperacillin as antibiotics were most of derivatives exhibited good activity. 展开更多
关键词 Synthesis ANTIMICROBIAL 3-Thioxo-1 2 4-Triazin-5-ones
下载PDF
H5Nx禽流感病毒交叉反应性CD4^(+) T细胞表位预测
7
作者 谢爽 陈瑶 黄俊琼 《生物技术通报》 CAS CSCD 北大核心 2024年第5期300-309,共10页
【目的】评估预先存在的H5Nx交叉反应性免疫记忆,为人类H5禽流感病毒的防治和广谱疫苗的研发提供理论数据。【方法】利用生物信息学方法筛选人源H5Nx禽流感病毒与季节性流感病毒的共同保守的交叉反应性CD4^(+) T细胞表位,进一步分析保... 【目的】评估预先存在的H5Nx交叉反应性免疫记忆,为人类H5禽流感病毒的防治和广谱疫苗的研发提供理论数据。【方法】利用生物信息学方法筛选人源H5Nx禽流感病毒与季节性流感病毒的共同保守的交叉反应性CD4^(+) T细胞表位,进一步分析保守表位嵌套CD8^(+) T细胞表位和B细胞表位情况以及在中国人群中的覆盖率。【结果】92.3%(513/555)的H5Nx CD4^(+) T细胞表位在季节性甲型流感病毒中具有交叉反应性,其中172个表位嵌套CD8^(+) T细胞表位和5个表位嵌套B细胞表位。这些表位与相应HLA-DRB1等位基因在全世界人群中的覆盖率为88.65%。【结论】由于反复接触季节性甲型流感病毒,人群中存在一定水平的的H5Nx交叉反应性免疫记忆,能够为H5Nx感染提供部分保护。 展开更多
关键词 h5Nx流感病毒 共同保守 交叉反应性 CD4^(+)T细胞表位 嵌套表位
下载PDF
New 4-imino-4H-Chromeno[2,3-d]Pyrimidin-3(5H)-Amine: Synthesis, Cytotoxic Effects on Tumoral Cell Lines and in Silico ADMET Properties
8
作者 Marwa Dhiabi Sirine Karoui +7 位作者 Mehdi Fakhfakh Souhir Abid Emmanuelle Limanton Rémy Le Guével Thierry Charlier Ludovic Paquin Jean-Pierre Bazureau Houcine Ammar 《International Journal of Organic Chemistry》 2024年第3期107-122,共16页
The synthesis of new 4-imino-4H-chromeno[2,3-d]pyrimidin-3(5H)-amine in four steps including one step under microwave dielectric heating is reported. The structural identity of the synthesized compounds was establishe... The synthesis of new 4-imino-4H-chromeno[2,3-d]pyrimidin-3(5H)-amine in four steps including one step under microwave dielectric heating is reported. The structural identity of the synthesized compounds was established according to their spectroscopic analysis, such as FT-IR, NMR and mass spectroscopy. These new compounds were tested for their antiproliferative activities on seven representative human tumoral cell lines (Huh7 D12, Caco2, MDA-MB231, MDA-MB468, HCT116, PC3 and MCF7) and also on fibroblasts. Among them, only the compounds 6c showed micromolar cytotoxic activity on tumor cell lines (1.8 50 50 > 25 μM). Finally, in silico ADMET studies ware performed to investigate the possibility of using of the identified compound 6c as potential anti-tumor compound. 展开更多
关键词 2-Amino-4h-Chromene 4h-Chromeno[2 3-d]Pyrimidin-3(5h)-Amine Microwave Irradiation Tumoral Cell Line in Silico ADMET
下载PDF
Highly efficient synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by heteropoly acids in water 被引量:6
9
作者 YingXiao Zong Yan Zhao +3 位作者 WenCai Luo Xing Hai Yu Jun Ke Wang Yi Pan 《Chinese Chemical Letters》 SCIE CAS CSCD 2010年第7期778-781,共4页
Heteropoly acids efficiently catalyzed the cyclocondensation reaction of anthranilamide with aldehydes in water at ambient temperature and afforded the corresponding 2,3-dihydro-4(1H)-quinazolinones compounds in goo... Heteropoly acids efficiently catalyzed the cyclocondensation reaction of anthranilamide with aldehydes in water at ambient temperature and afforded the corresponding 2,3-dihydro-4(1H)-quinazolinones compounds in good to excellent yields.This method provides mild reaction conditions and clean reaction profiles,using a small quantity of catalyst and a simple workup procedure. 展开更多
关键词 heteropoly acid 2 3-Dihydroquinazolin-4(1h)-ones WATER
下载PDF
Synthesis and Crystal Structure of 1-(4-Fluorophenyl)-2-hexylthiobenzo[4,5]-furo[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidin-5(1H)-one 被引量:4
10
作者 胡扬根 杜士明 +1 位作者 李清 丁明武 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2011年第1期75-78,共4页
The crystal structure of the title compound 1-(4-fluorophenyl) -2-hexylthio-benzo [4,5]furo[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidin-5(1H) -one(C23H21FN4O2S,Mr = 436.5) has been prepared and determined by single-cr... The crystal structure of the title compound 1-(4-fluorophenyl) -2-hexylthio-benzo [4,5]furo[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidin-5(1H) -one(C23H21FN4O2S,Mr = 436.5) has been prepared and determined by single-crystal X-ray diffraction. The crystal is of monoclinic,space group P21/n with a = 13.9854(3) ,b = 17.2678(4) ,c = 18.1828(5)A,β = 99.364(2) °,V = 4332.58(18) A^3,Z = 4,Dc = 1.338,F(000) =1824,μ = 0.185 mm^-1,MoKa radiation(λ = 0.71073) ,R = 0.0538 and wR = 0.1162 for 4728 observed reflections with I 〉 2σ(I) . X-ray diffraction analysis reveals the fused rings of benzo[4,5]furo[3,2-d]-1,2,4-triazolo[1,5-a] pyrimidin-5(1H) -one system are nearly coplanar. The crystal packing is mainly stabilized by weak intermolecular C-H···O hydrogen bond and π-π interactions. 展开更多
关键词 SYNThESIS crystal structure 1-(4-fluorophenyl)-2-hexylthio-benzo[4 5]furo[3 2-d]-1 2 4-triazolo[1 5-a]pyrimidin-5(1h)-one
下载PDF
Synthesis and Crystal Structure of(Z)-2-Methyl-5,6-dihydrobenzo[d]thiazol-7(4H)-one O-Prop-2-yn-1-yl Oxime Derivatives 被引量:3
11
作者 曹成桥 闫喜明 +2 位作者 杨权力 罗华军 黄年玉 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2014年第11期1683-1688,共6页
Compound(Z)-2-methyl-5,6-dihydrobenzo[d]thiazol-7(4H)-one O-prop-2-yn-1-yl oxime, C11H12N2 OS, as a synthetic precursor of cytotoxic triazoles has been prepared and characterized by NMR spectra. Meanwhile, the cry... Compound(Z)-2-methyl-5,6-dihydrobenzo[d]thiazol-7(4H)-one O-prop-2-yn-1-yl oxime, C11H12N2 OS, as a synthetic precursor of cytotoxic triazoles has been prepared and characterized by NMR spectra. Meanwhile, the crystal of IV was obtained and determined by X-ray single-crystal diffraction. Crystal data: monoclinic system, space group P21/c, a = 9.725(9), b = 8.068(7), c = 14.452(13)A, β = 98.68(2)°, V = 1120.9(17)A3, Z = 4, F(000) = 464, Dc = 1.305 g/cm^3, μ = 0.263 mm^-1, R = 0.0457 and w R = 0.1298 for 11511 independent reflections(Rint = 0.0709) and 2289 observed ones(I 〉 2σ(I)). 展开更多
关键词 X-ray diffraction crystal structure dihydrobenzo[d]thiazol-7(4h)-one cytotoxic activity TRIAZOLE
下载PDF
Synthesis and Crystal Structure of Trans-4-[(5-(2,4-Dichlorophenoxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl)methyleneamino]-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 被引量:4
12
作者 孙凤梅 田孟魁 +1 位作者 杨靖华 连照勋 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2008年第7期789-792,共4页
The title compound trans-4-[(5-(2,4-dichlorophenoxy)-3-methyl- 1-phenyl-1H-pyrazol-4-yl)methyleneamino]- 1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 3 (C28H23Cl2N5O2, Mr = 532.41) has been synthesized and its... The title compound trans-4-[(5-(2,4-dichlorophenoxy)-3-methyl- 1-phenyl-1H-pyrazol-4-yl)methyleneamino]- 1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 3 (C28H23Cl2N5O2, Mr = 532.41) has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in triclinic, space group P1- with a = 8.9438(4), b = 11.6065(5), c = 14.2215(6)A, α = 112.566(1), β = 92.324(2), γ = 102.91(1)°, V= 1315.65(10) A^3, Z = 2, Dc = 1.344 g/cm^3,μ(MoKa) = 0.282 mm^-1, λ = 0.71073 A, F(000) = 552, the final R = 0.0587 and wR = 0.1578 for 5071 observed reflections (I 〉 2σ(I)). X-ray analysis reveals that the product is a thermodynamically stable trans isomer. Intra- and intermolecular C( 12)-H(12)…O(1) and C(28)-H(28)...O(1)# 1 hydrogen bonds were observed in the title compound. 展开更多
关键词 trans-4-[ 5-(2 4-dichlorophenoxy)-3-methyl- 1-phenyl- 1h-pyrazol-4-yl)methylene amino]-1 5-dimethyl-2-phenyl-1 2-dihydropyrazol-3-one synthesis crystal structure
下载PDF
Design and Synthesis of Pyrido[1,2-e]purin-4(3H)-one Derivatives as Potential PDE 5 Inhibitors 被引量:1
13
作者 Guang Xin XIA Jian Feng LI +6 位作者 Shun An LAI Ai Ming PENG Shu Jun ZHANG Xiao Hui WEI Xin Jian CHEN Jing Shan SHEN Ru Yun JI 《Chinese Chemical Letters》 SCIE CAS CSCD 2005年第10期1283-1286,共4页
A novel series of pyrido[ 1,2-e]purin-4(3H)-one derivatives containing polar substituents on 5'-position were designed and prepared as potential PDE5 inhibitors. This paper reports the synthetic routes, 1H-NMR data... A novel series of pyrido[ 1,2-e]purin-4(3H)-one derivatives containing polar substituents on 5'-position were designed and prepared as potential PDE5 inhibitors. This paper reports the synthetic routes, 1H-NMR data, and the PDE5 inhibitory activities of the target compounds. The polar piperazinyl group contained (on 5'-position) compound, 3B2, showed the highest activity among the tested derivatives but less potency than sildenafil 1. 展开更多
关键词 Pyrido[1 2-e]purin-4(3h)-one PDE5 inhibitor SILDENAFIL erectile dysfunction (ED).
下载PDF
Synthesis of some new bis-3,4-dihydropyrimidin-2(1H)-ones by using silica-supported tin chloride and titanium tetrachloride 被引量:1
14
作者 Khodabakhsh Niknam Alireza Hasaninejad Madihe Arman 《Chinese Chemical Letters》 SCIE CAS CSCD 2010年第4期399-402,共4页
Silica-supported tin chloride and titanium tetrachloride were prepared by the reaction of tin chloride and titanium tetrachloride with activated silica gel in refluxing toluene.These solid acids have been employed as ... Silica-supported tin chloride and titanium tetrachloride were prepared by the reaction of tin chloride and titanium tetrachloride with activated silica gel in refluxing toluene.These solid acids have been employed as the catalysts for the synthesis of bisdihydropyrimidin -2(1H)-ones from aromatic dialdehydes,1,3-dicarbonyl compounds and urea at 90℃under solvent-free conditions. 展开更多
关键词 Silica-supported tin chloride Silica-supported titanium tetrachloride Bis-3 4-dihydropyrimidin-2(1h)-one SOLVENT-FREE 1 3-Dicarbonyl compounds
下载PDF
Synthesis and Crystal Structure of 2-(4’-Methylphenoxy)-5,8,9-trimethyl-3-phenyl Thieno[3′,2′:5,6]pyrido[4,3-d]pyrimidin-4-(3H)-one Hydrochloride 被引量:1
15
作者 LIU Jian-Chao HE Hong-Wu DING Ming-Wu 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2006年第5期577-581,共5页
The title compound 2-(4'-methylphenoxy)-5,8,9-trimethyl-3-phenyl thieno[3',2':5,6] pyrido[4,3-d]pyrimidin-4(3H)-one hydrochloride (C26H23Cl4N3O2S, Mr = 583.33) has been determined by single-crystal X-ray dif... The title compound 2-(4'-methylphenoxy)-5,8,9-trimethyl-3-phenyl thieno[3',2':5,6] pyrido[4,3-d]pyrimidin-4(3H)-one hydrochloride (C26H23Cl4N3O2S, Mr = 583.33) has been determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c with a = 14.8442( 11 ), b = 11.5131 (8), c = 17.2010(13) A, β = 113.7250(10)°, V = 2691.3(3) ,A^3, Z = 4, Dc = 1.440 g/cm^3, S = 1.094,μ = 0.547 mm^-1, F(000) = 1200, the final R = 0.0571 and wR = 0.1458. X-ray analysis reveals that the title compound combines with a molecule of dichloromethane by an intramolecular hydrogen bond. The thienopyridine ring is almost coplanar, and the dihedral angle between the thiophene plane and the pyridine plane is 0.6°. 展开更多
关键词 thieno[3' 2':5 6]pyrido[4 3-d]pyrimidin-4(3h)-one triphenylphosphine IMINOPhOSPhORANE crystal structure
下载PDF
茂金属配合物 [(eat^5-C_5H_4R)Mo(CO)_3]_2(R:SiMe_3,Si_2Me_5)的电子结构研究 被引量:12
16
作者 邝代治 冯泳兰 +3 位作者 许金生 王剑秋 张复兴 周秀中 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2003年第1期59-63,共5页
运用G98W ,采用Lanl2dz基组 ,对茂金属配合物 [(eat5 C5H4R)Mo(CO) 3 ]2 (R :SiMe3 ,Si2 Me5)进行从头算研究 ,探讨配合物结构单元的稳定性、分子轨道能量、原子净电荷布居规律 ,以及一些前沿分子轨道的组成特征等 ,结果表明 ,标题配合... 运用G98W ,采用Lanl2dz基组 ,对茂金属配合物 [(eat5 C5H4R)Mo(CO) 3 ]2 (R :SiMe3 ,Si2 Me5)进行从头算研究 ,探讨配合物结构单元的稳定性、分子轨道能量、原子净电荷布居规律 ,以及一些前沿分子轨道的组成特征等 ,结果表明 ,标题配合物结构在能量上是稳定的 ,作为结构单元而存在 . 展开更多
关键词 茂金属配合物 [(eat^5-C5h4R)Mo(CO)3]2 从头计算 电子结构
下载PDF
微波辐射下“一锅煮”法合成2-氨基-3-氰基-4-芳基-4H,5H-吡喃-[3,2-c]苯并吡喃-5-酮 被引量:8
17
作者 蒋虹 屠树江 +5 位作者 房芳 朱松磊 李团结 章晓镜 史达清 王香善 《有机化学》 SCIE CAS CSCD 北大核心 2004年第11期1458-1460,共3页
以芳醛、4 羟基香豆素、丙二腈为原料 ,乙醇为能量转移剂 ,哌啶为催化剂 ,在微波辐射下一步合成了一系列 2 氨基 3 氰基 4 芳基 4H ,5H 吡喃 [3 ,2 c]苯并吡喃 5 酮 ,反应在 40~ 60s时间内完成 ,产率 60 %~ 97% .
关键词 微波辐射 “一锅煮”法 合成 2-氨基-3-氰基-4-芳基-4h 5h-吡喃-[3 2-c]苯并吡喃-5-酮 芳醛 4-羟基香豆素 丙二腈
下载PDF
MgSO_4·5Mg(OH)_2·3H_2O的水热合成及反应时间对其形貌的影响(英文) 被引量:18
18
作者 朱黎霞 岳涛 +1 位作者 高世杨 夏树屏 《无机化学学报》 SCIE CAS CSCD 北大核心 2003年第1期99-102,共4页
Both whisker and nanometer MgSO4·5Mg(OH)2·3H2O(MOS) were prepared by hydrothermal method at 140℃for different times, using NaOH and MgSO4·7H2O as raw materials. The MgSO4·5Mg(OH)2·3H2O part i... Both whisker and nanometer MgSO4·5Mg(OH)2·3H2O(MOS) were prepared by hydrothermal method at 140℃for different times, using NaOH and MgSO4·7H2O as raw materials. The MgSO4·5Mg(OH)2·3H2O part icles were characterized by powder X ray diffraction(XRD),thermal analysis(TGA DSC), infrared spectroscopy(FT IR),transmission electron microscopy(SEM) and scanning electron microscopy(TEM). The size distribution in whisker like and nanocrystalline materials arein the range of 10~50μm and 10~20nm respectively. The whisker MOS is metastable phase in MgSO4 NaOH H2O system at 140℃,whereas nanometer MOS is stable phase. 展开更多
关键词 MgSO4·5Mg(Oh)2·3h2O 水热合成 反应时间 形貌 硫氧镁
下载PDF
铕配合物[C_5H_5NC_(16)H_(33)][Eu(TTA)_4]在改性介孔材料Si-MCM-41孔道中的组装研究 被引量:8
19
作者 徐庆红 李洪武 +2 位作者 李连生 邹永存 徐如人 《高等学校化学学报》 SCIE EI CAS CSCD 北大核心 2003年第10期1758-1760,共3页
It was proved by ICP, fluorescence spectra and N 2 adsorption that the rare earth complex [C 5H 5NC 16H 33] [Eu(TTA) 4] is in the channel of Si-MCM-41 in the course of assembly. The rare earth complex of 67.9% is in t... It was proved by ICP, fluorescence spectra and N 2 adsorption that the rare earth complex [C 5H 5NC 16H 33] [Eu(TTA) 4] is in the channel of Si-MCM-41 in the course of assembly. The rare earth complex of 67.9% is in the channel, suggesting that the assembly of the complex molecular on the mesoporous MCM-41 was carried out mainly in the channel. 展开更多
关键词 铕配合物 [C5h5NC16h33][Eu(TTA)4] 改性 介孔材料 Si-MCM-41 孔道 组装 介孔二氧化硅
下载PDF
稳定剂NH_4H_2PO_4用于胶体Sb_2O_5阻燃剂的制备及稳定作用研究 被引量:5
20
作者 王海棠 汪小伟 +2 位作者 张渭渊 张新义 杨芬芬 《精细化工》 EI CAS CSCD 北大核心 2003年第2期105-108,共4页
采用NH4 H2 PO4 为稳定剂 ,以H2 O2 为氧化剂 ,将Sb2 O3 氧化 ,制得胶体Sb2 O5。通过正交实验法优选出最佳制备工艺条件为 :n(H2 O2 ) /n(Sb2 O3 ) =3,m (H2 O) /m(Sb2 O3 ) =3~ 4,m(NH4 H2 PO4 ) /m(Sb2 O3 ) =0 0 5 ,温度 90℃ ,反... 采用NH4 H2 PO4 为稳定剂 ,以H2 O2 为氧化剂 ,将Sb2 O3 氧化 ,制得胶体Sb2 O5。通过正交实验法优选出最佳制备工艺条件为 :n(H2 O2 ) /n(Sb2 O3 ) =3,m (H2 O) /m(Sb2 O3 ) =3~ 4,m(NH4 H2 PO4 ) /m(Sb2 O3 ) =0 0 5 ,温度 90℃ ,反应 1 5h。该条件下 ,Sb2 O3 转化率达到 98%,制得胶体中w(Sb2 O5) =2 1%,透光率 90 %,胶粒平均粒径为 84nm左右。实验结果表明 :采用NH4 H2 PO4 作为稳定剂 ,可使Sb2 O5粒子稳定存在 1a以上而不发生聚沉。 展开更多
关键词 稳定剂 Nh4h2PO4 胶体Sb2O5 阻燃剂 制备 稳定作用 研究 五氧化二锑 磷酸二氢铵 转化率 透光率
下载PDF
上一页 1 2 27 下一页 到第
使用帮助 返回顶部