共查询到20条相似文献,搜索用时 125 毫秒
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开展了微波辅助法合成MCM-22分子筛的研究, 经过29 h微波晶化得到了与传统水热法合成5 d相同的100%晶化的样品, 有效地缩短了合成时间. 通过XRD, SEM, FT-IR, ICP和27Al MAS NMR技术表征, 微波辅助合成样品具有高纯度、均一形貌, Al原子有效进入骨架等特征. 对合成中的关键性条件, 如结构导向剂的含量进行了深入研究, 并给出了可能的合成机理. 此外, 通过在合成液中添加少量高介电损失物质, 进一步缩短了合成时间. 相似文献
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黄烷酮是含有二氢色原酮骨架结构的黄酮类化合物。本文梳理了合成黄烷酮的文献,总结了其合成方法,按原料结构特征分类论述其合成方法:即从黄烷酮衍生物经官能团变换合成黄烷酮;查耳酮经氧-Michael加成合成黄烷酮;非查耳酮结构构建合成黄烷酮。重点论述了第二类合成方法。参考文献82篇。 相似文献
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Mamoru Ito Yu‐ki Tahara Prof. Dr. Takanori Shibata 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(16):5468-5477
Clavicipitic acid is an ergot alkaloid, which was isolated from Claviceps strain and Claviceps fusiformis. Its unique tricyclic azepinoindole skeleton has attracted synthetic chemists, and various strategies have been developed for its total synthesis. These strategies can be generally categorized into two types based on the synthetic intermediates, namely, 4‐substituted gramine derivatives and 4‐substituted tryptophan derivatives. This Minireview summarizes the reported total syntheses from the point of these two key intermediates 相似文献
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N-芳基氮氧方酸的活性羟基能够被芳伯胺取代。利用这一特性,可在方酸四碳环上引入另一不同的芳胺基,即可获得不对称芳基取代的方酰胺或异方酰胺。以乙醇等为介质,芳伯胺与7种N-芳基氮方酸反应,制得25个不对称的方酰胺和24个不对称的异方酰胺。该合成方法优点突出,反应简便有效,通用性强。 相似文献
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Pengfei Cai Zhan Gao Xinchi Yin Yuanqing Luo Xiaoyong Zhao Yuanjiang Pan 《Journal of separation science》2019,42(23):3589-3598
Mandelic acid and its derivatives are important medical intermediates in the pharmaceutical industry. Different stereoisomers exhibited distinct biological properties to human bodies. Given that, enantioselective recognition and separation of mandelic acid are of great importance. In this study, four novel different types of chiral ionic liquids bearing designed functional groups were synthesized and successful enantioselective precipitation with mandelic acid and its derivatives. That is, (R, R)‐chiral ionic liquid 1 can coprecipitated with S‐mandelic acid and its derivatives was observed. In addition, good correlation coefficient is achieved by using electrospray mass spectrum at negative ion pattern for quick analysis of the enantioselective precipitation, which could be served as a method of enantioselective recognition. The possible intermolecular interactions are established after systematical studies by NMR spectroscopy and DFT calculations. 相似文献
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Patcharee Ngamviriyavong Paweena Uppanan Wanida Janvikul 《Macromolecular Symposia》2008,264(1):135-139
Amino acid modified chitooligosaccharides were synthesized by the new synthetic route. The chloroacetyl-chitooliogosaccharide intermediates were prepared under a mild condition via a reaction between chitooligosaccharide (COS) and chloroacetic anhydride. The intermediates were subsequently reacted with a variety of amino acids, e.g., glycine, aspartic acid, alanine, arginine, and serine, under a basic condition, yielding amino acid modified COS products. The degree of chloroacetylation was calculated based on new 1H NMR absorption peaks at 3.80 and 3.94 ppm, corresponding to NH CO CH2 Cl and O CO CH2 Cl, respectively. The degrees of chloroacetylation determined were 0.40, 0.44, 0.62, and 0.93 when the mole ratios of chloroacetic anhydride to COS were 0.5, 1, 2, and 4, respectively. The chemical structures of the COS derivatives were also determined using 1H NMR spectroscopy. The biological properties of the derivatives were evaluated. Cytotoxicity of the derivatives was assessed by a direct contact, using L929 cells. An MTT assay was a method of choice to evaluate the efficacy of the derivatives to enhance the proliferation of L929 cells. 相似文献
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l,4-Bis(chloromethyl) benzene (BCMB) and its derivatives are very important intermediates of much synthetic reaction. Especially, they can be used to synthesize poly(p-phenylene vinylene) (PPV) and its alkoxy derivatives, which have aroused significant interest in recent years[l,2]. So people pays close attention to the synthesis of BCMB derivatives. There are several methods to synthesize BCMB derivatives, such as applying HCHO or (HCHO)n with concentrated hydrochloric acid or anhydrous HCl in the presence of zinc chloride, adopting (HCHO)n with hydrochloric acid in acetic acid aqueous, or utilizing HCHO reacts with hydrochloric acid and bubbles anhydrous HCl which was so called Wood method[3].The methods mentioned above usually affored low yield of BCMB substituted by long alkoxy group, while the synthesis of BCMB with long alkoxy-substituents are the essential for the synthesis of soluble PPV derivatives[4,5]. 相似文献
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桦木酸是一种羽扇豆烷型的五环三萜类化合物,因具有显著的抗肿瘤和抗HIV病毒特性而受到人们关注。桦木酸存在于多种植物中,可以用提取法得到,但由于桦木酸在植物中含量低,其主要来源是由合成法得到。许多桦木酸衍生物也具有抗肿瘤活性。本文介绍了桦木酸的提取与合成等制备方法,以及几种桦木酸衍生物的合成路线,并对桦木酸及其衍生物的抗肿瘤途径和机理进行了概述。 相似文献