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三氮唑的合成方法 总被引:1,自引:0,他引:1
<正> 1 概述三氮唑即1,2,4-三氮唑又称1,2,4-三唑(简称三唑),为无色针状晶体或结晶粉末,是一种重要的精细化工原料,熔点120~121℃,溶于水和乙醇,被广泛地应用于农药、医药、染料和橡胶助剂工业,也可用做复制系统的光电导体,是重要的有机化工中间体。早在本世纪30年代,三唑的制备研究已经开始,到60年代,国外文献开始广泛讨论三唑的制备如以甲酰胺、甲酰肼、水合肼、盐酸肼等为主要原料制取三唑。70年代初,Bayer公司使用三唑合成了一种具有特异性能的杀菌剂三唑酮。三唑酮类化合物在许多病虫害的防治上具有优良的效果而得到广泛的应用,它的迅速发展也为三唑的开发研制提供了广阔的前景。 相似文献
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研究了1H-1,2,3-三氮唑的新的合成工艺,以水合肼,盐酸羟胺,乙二醛为原料,经肟化、腙化、脱乙酰基等反应进行制备、优化。该新路线与传统工艺相比,全部采用工业原料,价格低,生产成本低,易于工业化,1H-1,2,3-三氮唑含量99.6%(色谱法)。 相似文献
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介绍用邻硝基氯苯与水合肼为原料合成 1-羟基苯并三氮唑 ,再还原成苯并三氮唑。较好的工艺条件为反应温度为 85℃ ,时间为 4h ,用乙酸乙酯为萃取剂 ,铁粉分次加入。 相似文献
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氯甲基三唑盐酸盐的合成 总被引:1,自引:0,他引:1
本文介绍了三唑类农药中间体氯甲基三唑盐酸盐的合成方法,以1H-1,2,4-三唑,多聚甲醛为主要原料合成羟甲基三唑,再与氯化亚砜进行反应,合成氯甲基三唑盐酸盐,合成总收率为89.2%。 相似文献
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合成了三种含酯基和三种含醚键的炔单体,通过核磁共振氢谱(1H NMR)、红外光谱(FT-IR)、质谱(MS)、液相色谱(LC)对其结构进行了表征。用这六种炔单体与叠氮单体反应制备了一系列新型聚三唑酯树脂(PTAE)和聚三唑醚树脂(PTAO)。利用差示扫描量热分析(DSC)、FT-IR、动态力学热分析(DMA)、力学试验机和热失重分析(TGA)表征了树脂的固化行为、固化树脂的力学性能、耐热性和热稳定性。结果表明PTAE和PTAO树脂易溶于有机溶剂,可低温(60℃)固化,固化树脂的弯曲强度超过了100 MPa,可达158 MPa,玻璃化转变温度(T g)超过180℃,高者达251℃,热分解温度可达360℃。 相似文献
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Epigenetics regulates gene expression, cell type development during differentiation, and the cell response to environmental stimuli. To survive, bacteria need to evade the host immune response. Bacteria, including Helicobacter pylori (Hp), reach this target epigenetically, altering the chromatin of the host cells, in addition to several more approaches, such as DNA mutation and recombination. This review shows that Hp prevalently silences the genes of the human gastric mucosa by DNA methylation. Epigenetics includes different mechanisms. However, DNA methylation persists after DNA replication and therefore is frequently associated with the inheritance of repressed genes. Chromatin modification can be transmitted to daughter cells leading to heritable changes in gene expression. Aberrant epigenetic alteration of the gastric mucosa DNA remains the principal cause of gastric cancer. Numerous methylated genes have been found in cancer as well as in precancerous lesions of Hp-infected patients. These methylated genes inactivate tumor-suppressor genes. It is time for us to complain about our genetic and epigenetic makeups for our diseases. 相似文献
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Three series of metronidazole-flavonoid derivatives were generated and evaluated for antimicrobial activity against H. pylori. Among these compounds, high anti-H. pylori activities were observed in isoflavones derivatives 4-7, 19, and 20 but exhibited no inhibitory activity against other sorts of bacteria and fungi, for example, Streptococcus pneumoniae, Bacillus subtilis, Escherichia coli, Pseudomonas fluorescence, and Aspergillus niger. Genistein derivative 6 with the potent activity (MIC=0.39 microg mL(-1)) was >50-fold more than metronidazole, and comparable to the positive control amoxicillin. Additionally, compound 6 can significantly attenuate the increase in interleukin-8 (IL-8) levels in the AGS cells stimulated by H. pylori water extract (HPE) at concentrations of 15, 30, and 60 micromol L(-1), which did not show any effects on the cell viability. 相似文献
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We prepared three new poly(9,9-dihexylfluorene) derivatives (P1–P3) containing kinked aromatic triazole (triphenyl-1,2,4-triazole derivative) via Suzuki coupling polymerization. These copolymers were soluble in common organic solvents and showed high decomposition temperatures (Td = 416–454 °C). The optical and electrochemical properties of P1–P3 were compared with poly(9,9-dihexylfluorene) (PFO) and P4 and P5 in which the linkages of the aromatic triazole were different. After introducing the triazole units, absorption spectra showed blue shift (388 nm → 372 nm) due to reduced conjugation, but PL spectra remained almost unchanged (417–418 nm). The linkages of triazole with fluorene segments in P1–P5 were different: (1) fluorene segments linked with triazole through a kinked angle (P1 and P2), (2) triazole as a branch unit (P3) and as terminal groups (P4), (3) fluorene segments linked with triazole in a linear way (P5). As estimated from semi-empirical MNDO calculation, two twisted conformations (ca. 90° each) exist between triazole core and fluorene groups. These kinked conformation and twisted structure increased the PL efficiency (ΦPL = 0.60–0.73, ΦPL = 0.58 for PFO) and partially inhibited annealing-induced excimer formation. From cyclic voltammetric results, P1–P3 exhibited better electron affinity (LUMO: −2.75 to −2.82 eV) than PFO (LUMO: −2.52 eV). 相似文献
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目的 克隆幽门螺杆菌(Helicobacter pylori,HP)过氧化氢酶(katA)基因并在大肠杆菌中进行表达。方法 采用PCR扩增幽门螺杆菌katA全长基因,将其克隆入pET-11c载体中,经测序证实后,在大肠杆菌中进行表达,产物用Western blot检测其抗原性并进行N末端氨基酸的测序。结果 幽门螺杆菌katA基因全长1 518bp,编码氨基酸505个。在BL21(DE3)中的表达量约占细菌总蛋白的24.9%,表达产物经SDS-PAGE显示其相对分子质量与软件预测结果 58 000相符,N末端5个氨基酸测序结果与Hp中天然的katA完全一致,经Western blot检测可被 Hp全菌抗血清识别。结论 katA能在大肠杆菌中进行高效表达,具有良好的免疫反应性,可望为研究 Hp的致病机理、实验诊断及亚单位疫苗等提供充足的katA原材料。 相似文献
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目的 确定感染率高且稳定的幽门螺杆菌感染动物模型预处理方案。方法 取蒙古沙鼠200只,随机分为3个实验组及1个对照组。实验组沙鼠在断食、水12h后分别应用pH2盐酸、消炎痛+胃复安和50%乙醇3种不同方案进行预处理,对照组用生理盐水处理。此后继续断食、水12h,再灌喂Hp菌液(109cfu/ml)0.5ml/只。共3次,每次间隔12h。最后1次灌喂后2h给食、水。后每隔4周解剖一批动物,每组10只,进行分离培养、ELISA、PCR、快速尿素酶检测和病理切片检查。结果3组实验动物感染率不同,其中50%乙醇组沙鼠感染率相对较高,达到80%,其病理组织学变化与人体相应病变也极为相似。结论50%乙醇组沙鼠预处理方案感染效果最好,可作为Hp感染动物模型的预处理方法。 相似文献