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四(三苯基膦)化钯催化的若干菲啶类化合物的合成 总被引:1,自引:0,他引:1
邻甲酰基芳基硼酸与取代邻溴苯胺经四(三苯基膦)化钯催化偶联缩合, 合成了9个菲啶衍生物。邻溴苯胺的取代基无论是吸电子或供电子基团, 反应均可顺利进行。 相似文献
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利用廉价易得的2-乙烯基苯胺与重氮化合物在三氟乙酸催化下发生[5+1]环化反应, 以中等至良好的产率合成了24种2-芳基喹啉衍生物. 该方法无需金属催化剂, 官能团兼容性好, 反应成本低, 不仅拓展了重氮化合物参与的新型有机反应, 同时也为2-芳基取代喹啉的合成提供了高效、 经济且简洁的新方法. 相似文献
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邻苯二酚甲基化合成愈创木酚 总被引:7,自引:0,他引:7
愈创木酚是一种重要的化工原料 ,可用于合成止咳祛痰的药物愈创木酚磺酸钾和香料香兰素 .目前愈创木酚是由邻甲氧基苯胺重氮化反应制得 ,工艺路线长 ,产率低 .本文由邻苯二酚和硫酸二甲酯反应合成愈创木酚取得较好的结果 相似文献
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以5步反应从邻碘苯甲酸乙酯合成了9,10-二氢-9,9,10,10-双(γ-丁内酯)菲,减少了3步反应,总产率提高7%.又由邻碘苯甲酰氯与乙烷-1,1,2-三羧酸三乙酯缩合,继以消除两个乙酯基合成Dallacker双内酯,反应减少一步,产率则增高13%.还研究了联苯-2,2-二甲酰氯分别与乙烷-1,1,2-三羧酸三乙酯和氰基琥珀酸二乙酯的缩合,均能得到良好的产率. 相似文献
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氧连接氮乙酰葡萄糖胺(O-GlcNAc)是一种重要的蛋白质翻译后修饰,它在维持机体正常的生命活动中发挥着重要作用。许多研究证实,O-GlcNAc糖基化修饰稳态的破坏与人类多种疾病的发生相关,大规模富集鉴定O-GlcNAc糖基化修饰蛋白有助于发现新的临床疾病诊断标志物。由于O-GlcNAc糖基化修饰丰度较低,形成的糖苷键不稳定,O-GlcNAc糖基化修饰蛋白/肽段的富集鉴定面临一定挑战。近年来,全乙酰化的非天然糖代谢标记技术被广泛应用于O-GlcNAc糖基化修饰蛋白/肽段的富集鉴定。然而,最新的研究发现,在细胞代谢标记过程中,全乙酰化的非天然单糖会同时标记半胱氨酸的巯基而引入半胱氨酸巯基-叠氮糖人为修饰物。该副反应在一定程度上干扰了O-GlcNAc糖基化修饰蛋白/肽段的富集鉴定。鉴于此,研究发展了一种通过三甲基苯磺酰羟胺(MSH)特异性氧化消除半胱氨酸巯基-叠氮糖人为修饰物的方法,进而显著提高O-GlcNAc糖基化修饰肽段的精准鉴定。该方法建立于温和的磷酸钠缓冲液(50 mmol/L, pH=8)体系,利用过量的MSH,于95 ℃避光振荡反应30 min,可完全消除半胱氨酸巯基-叠氮糖人为修饰物。该方法应用于Hela细胞中,可有效消除叠氮全乙酰化半乳糖胺(Ac4GalNAz)代谢产生的半胱氨酸巯基-叠氮糖人为修饰物,从而成功富集鉴定到157条O-GlcNAc糖基化修饰肽段,归属于130个蛋白质。该方法有效去除了半胱氨酸巯基-叠氮糖人为修饰物对代谢标记结果的干扰,为非天然糖代谢标记技术在糖蛋白组学分析中的应用提供了新的研究策略。 相似文献
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硅醚类化合物广泛应用于有机合成、 分离分析和精细化工等领域. 六甲基二氮硅烷是近年来发展的一种新型硅基化试剂, 被用于硅醚的高效合成, 但由于六甲基硅烷较为惰性, 通常需要加入催化剂活化. 本文报道了一种无催化剂下醇、 酚的高效硅基化新方法. 研究结果表明, 该方法可以兼容一级苄醇、 杂芳基苄醇、 脂肪醇, 二级醇甚至三级醇, 多数反应可以实现定量转化, 无需柱层析即可实现产物的分离纯化. 该方法可以拓展到酚的高效硅醚化, 也可以很方便地放大到100 mmol, 收率达到99%, 表明该方法具有较好的实用价值. 相似文献
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Wahid M. Basyouni Nagwa M. Abdelazeem Khairy A. M. El-Bayouki Mohamed Y. El-Kady 《合成通讯》2013,43(22):3112-3120
A simple and efficient eco-friendly method was developed for the synthesis of new benzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitrile derivatives in excellent yields. The synthesis was achieved through the reaction of 2-aminobenzimidazole, aldehydes and active nitriles (malononitrle or ethyl cyanoacetae) in the presence of silica sulfuric acid/ethylene glycol. This protocol offers very short reaction times (in some cases, reaction times were reduced to five minutes), high yields and low cost. This method thus provides an improvement over the existing methods. 相似文献
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Highly efficient ring opening reactions of epoxides with deactivated aromatic amines catalyzed by heteropoly acids in water 总被引:1,自引:0,他引:1
Najmedin Azizi 《Tetrahedron》2007,63(4):888-891
Heteropoly acid was found to be an effective and efficient catalyst for the ring opening reaction of epoxides with various aromatic amines to produce the corresponding β-amino alcohols in moderate to excellent yields in water. This method provides a new and efficient protocol in terms of mild reaction conditions, clean reaction profiles, small quantity of catalyst, and simple work-up procedure. 相似文献
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[reaction: see text] A new and efficient palladium-catalyzed reaction of o-diiodoarenes with internal alkynes produces naphthalenes or anthracenes in good to excellent yields. This procedure provides a simple, catalytic, and straightforward ring-extension method for constructing substituted polycyclic aromatic compounds. 相似文献
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蛋白质糖基化是生物体内最重要的翻译后修饰之一,在蛋白质稳定性、细胞内和细胞间信号转导、激素活化或失活和免疫调节等生理过程和病理进程中发挥重要作用。而异常的蛋白质糖基化往往和多种疾病的发生发展密切相关,目前应用于临床检测的多种肿瘤生物标志物大多属于糖蛋白或者糖抗原。因此在组学层次系统分析蛋白质糖基化的变化对阐明生物体内糖基化修饰的调控机理和发现新型疾病标志物都非常重要。基于质谱的蛋白质组学技术为全面分析蛋白质及其修饰提供了有效的分析手段。在自下而上的蛋白质组学研究中,由于完整糖基化肽段同时存在性质各异的肽段骨架和糖链结构、糖肽的相对丰度和离子化效率较低以及糖基化修饰有高度异质性等特点,完整糖肽的分析比其他翻译后修饰更加困难。近年来,为了更全面、系统地分析蛋白质糖基化,研究人员发展了一些新技术,包括完整糖肽的富集技术、质谱的碎裂模式和数据采集模式、质谱数据的解析方法和定量策略等等,大力推进了该领域的研究水平,也为研究蛋白质糖基化相关的生物标志物提供了技术支持。该篇综述主要关注近年来基于质谱的糖蛋白质组学研究中的新进展,重点介绍针对完整N-和O-糖基化肽段的富集新技术和谱图解析新方法,并讨论其在肿瘤早期诊断方面的应用潜力。 相似文献
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The (COCl)2/Hantzsch ester is found to be an effective system for the metal-free reduction of tertiary phosphine oxides. The reaction proceeds under mild conditions, and is applicable to triarylphosphine oxides and alkyldiarylphosphine oxides to produce the corresponding tertiary phosphines in good to excellent yields. This new finding provides a practical, convenient and metal-free method for the reduction of tertiary phosphine oxides to tertiary phosphines, and shows potential application in organic synthesis. 相似文献
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Patricia Gizecki Ramzi Ait Youcef Cline Poulard Robert Dhal Gilles Dujardin 《Tetrahedron letters》2004,45(52):9589-9592
Under Lewis acid conditions, reaction of N-Boc, O-Me acetals with the (R)-(+)-O-vinyl-pantolactone does not lead to the expected dihydrooxazine, but to the corresponding tetrahydrooxazinone, as a result of the loss of the t-Bu group. A diastereoselective and asymmetrical way to these new heterocyclic compounds is described, together with the first evidence of their ability to undergo N-acylation. 相似文献
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A palladium-/copper-catalyzed intermolecular C-H amination reaction of indoles has been developed. This reaction proceeds in good to excellent yields to produce a variety of 2-amino-substituted indoles and exhibits excellent regioselectivity at room temperature. Furthermore, chloroamination of indoles provides a simple method for the construction of C-N and C-Cl bonds in one step. 相似文献
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Ajayan Vinu Mani Karthik Masahiko Miyahara Velayudam Murugesan Katsuhiko Ariga 《Journal of molecular catalysis. A, Chemical》2005,230(1-2):151-157
CoAl-MCM-41 (X) catalysts with X = nSi/(nCo + nAl) various ratios were synthesized and ethylation of phenol with ethanol was studied in vapor-phase at temperatures between 250 and 450 °C. The products obtained were O-alkylated product (ethyl phenyl ether), C-alkylated products (2-ethylphenol and 4-ethylphenol), and C-/O-alkylated products (ethyl ethylphenyl ether). The phenol conversion increased significantly with reaction temperature over all the catalysts. The activity of the catalysts followed the order CoAl-MCM-41 (20) > CoAl-MCM-41 (50) > CoAl-MCM-41 (80). Selectivity between the C-alkylation and the O-alkylation depended on the factors such as acidity of the catalyst and the reaction temperature. CoAl-MCM-41 (20) catalyst displayed a phenol conversion of 40% and a selectivity of more than 80% for 2-ethylphenol under the optimized reaction condition. The ethanol to phenol ratios and the reactant flow rate are also influential for both activity and selectivity of CoAl-MCM-41 catalysts. 相似文献