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选择性去甲醚化反应———2,6—二甲氧基苯酚的新合成方法 总被引:1,自引:0,他引:1
选择性去甲醚化反应——2,6-二甲氧基苯酚的新合成方法吴安心王明义潘鑫复*(兰州大学化学系730000)2,6-二甲氧基苯酚是研究Claisen重排,合成其它化合物[1]以及天然产物[2]的重要前体。它的制备仅依据于早期R.B.Krauss的方法[3... 相似文献
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丹皮酚的选择性溴化反应 总被引:4,自引:0,他引:4
丹皮酚 (Paeonol)化学名为 4 甲氧基 2 羟基苯乙酮 ,是中药材牡丹皮中所含的主要活性成分 ,具有抑菌抗炎、解热镇痛 ,降压利尿 ,抗凝血 ,抑制肿瘤 ,抗癌 ,增强免疫功能等作用[1~ 3] ,在医药、香料、化工领域具有广泛的用途。对丹皮酚进行选择性溴代是进一步开发丹皮酚药用价值的有效途径之一。α 卤代酮是有机合成的中间体 ,一般是在酸催化下用卤素直接卤化制得[4] 。但丹皮酚的苯环较活泼 ,若用溴直接作溴化剂 ,苯环和侧链羰基α 氢可同时发生反应。陈俊杰等[5] 用溴化铜作为羟基苯乙酮的α 溴化剂 ,有较高的选择性 ,溴代只发生在侧链羰… 相似文献
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Dr. Chady Moussallem Dr. Simon Olivier Jérémie Grolleau Magali Allain Dr. Charlotte Mallet Dr. Gurunathan Savitha Dr. Frédéric Gohier Prof. Dr. Pierre Frère 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6510-6514
Aromatization of 4‐cyano‐3‐oxotetrahydrothiophene by sulfuryl chloride gives the new building block 4‐cyano‐3‐pyrrolidylthiophene, which forms unsymmetrical regioregular oligothiophenes with a strict alternation of the donor and acceptor groups along the conjugated system. The self‐coupling reactions that form the oligomers are shown to proceed by a regioselective electrophilic aromatic substitution mechanism involving a stabilized Wheland intermediate. 相似文献
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以2,6-二氟苯胺为原料,经溴化、重氮化和 Sandermer反应合成液晶中间体4-溴-2,6-二氟苯基氰,研究了反应条件对反应的影响,各步骤产物结构经IR、MS、NMR分析数据得以确定。 相似文献
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Synthesis of unsymmetrical allylic chlorides has been accomplished using cyanuric chloride in combination with DMF through ipso‐substitution and tele‐substitution by judicious choice of the substituents at appropriate positions of unsymmetrical allyl alcohols, taking care of their electronic and steric properties. 相似文献
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Origin of the Regioselectivity in the Gas‐Phase Aniline+CH3+ Electrophilic Aromatic Substitution 下载免费PDF全文
Dr. Daniel Kinzel Prof. Shmuel Zilberg Prof. Dr. Leticia González 《Chemphyschem》2015,16(11):2366-2374
Nonadiabatic ab initio molecular dynamics simulations are carried out to monitor the attack of CH3+ on aniline in the gas phase to form the corresponding σ complexes. The reaction is ultrafast and is governed by a single electron transfer within 30 fs, which involves two sequential conical intersections and finally produces a radical pair. Positive‐charge allocation in the aromatic compound is found to govern the substitution pattern in ortho, meta, or para position. Although the major products in the first step of the electrophilic aromatic substitution are the ortho and para σ complexes, initially 26 % of the simulated trajectories also form meta complexes, which then undergo H shifts, mainly to the para position. 相似文献
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Thephenolscontainingalkenylunitslarealargegroupofinterestingnaturalproductsexhibitingmanyphysiologicalfunctionssuchasantiflammatory,antibacterialandantioxidativeactivities2.Twonovelacetophenones1and2wererecentlyisolatedfromthefruitsofEvodiamerrillii,asmallfolkmedicinaltreewidelydistributedinTaiwan',andtheaerialpartsofBorroniaromosainAustraliangenusBoroniarespectively'.Theirstructureswereelucidatedas4-(l'-geranyl)-2,6-dihydroxyacet1and4-(l'-farnesyl)-2,6-dihydroxyacetophen2bymeansofspectrosco… 相似文献
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Regioselective Synthesis and Base Catalyzed Transacylation of Substituted 1H—Pyrazole—4—carboxamides
New type of substituted 1H-pyrazole-4-carboxamides were obtained by regioselective synthesis under the catalysis of different based.The stuctures of the title compounds were confirmed by elemental analysis,^1H NMR,IR,MS and X-ray crystallography.Compounds 1 were transcaylated into their corresponding.Compounds 1 were transacylated into their corresponding amides 3 in the prsence of sodium hydride.Preliminary bioassays indicated that some compounds showed fungicidal activities against Rhizoctonia solani and Sclerotinia sclerotiorum. 相似文献
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两种邻、间手性二醇的区域选择性取代反应研究 总被引:1,自引:0,他引:1
对两种邻、间手性二醇的区域选择性取代反应进行了研究. 以(R)-(-)-1,3-丁二醇(1)为起始原料, 在各种有机碱存在下, 先合成C1-位单磺酸酯, 进行C1-位的单醚化取代, 均有非区域选择性的单(双)取代物生成. 若用SOCl2处理1, 使其首先生成环状亚硫酸酯中间体5, 苯硫酚在2% Na2CO3存在下可和其发生高区域选择性取代反应, 生成 (R)-(-)-3-羟基-丁基苯硫醚(3). 以同样的方法使(S,R)-(+)-1-(6-氟-2-色满基)-1,2-乙二醇(6)和SOCl2反应生成环状亚硫酸酯(9), 再和苄胺反应, 也可发生高区域选择性取代, 生成 (S,R)-(+)-2-苄氨基-1-(6-氟-2-色满基)-乙醇(8). 该反应方法具有高区域选择性, 产物有高旋光纯度、高产率. 相似文献
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蔗糖酯的酶催化区域选择性合成 总被引:9,自引:0,他引:9
酶可以区域选择性地合成蔗糖酯,枯草杆菌等蛋白酶被用来区域选择性合成 1'-O-蔗糖酯,且通常不接受长链(大于C_(12))脂肪酸作为酰基授体,而脂肪酶可 催化宽范围的脂肪酸,除了脂肪酶和蛋白酶外,研究发现抗体酶也能区域和立体选 择地酰化蔗糖。蔗糖二酯、线型蔗糖酯都可以通过酶催化区域选择性地合成。酶催 化合成蔗糖酯通常在二甲基甲酰胺、二甲基亚砜和吡啶等有毒溶剂中进行。近几年 来,无溶剂条件下酶催化合成蔗糖酯,以及用叔丁醇等毒性较小的溶剂代替毒性较 大的溶剂的研究,也越来越受重视。 相似文献