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以香兰素为原料、以Heek反应为关键反应构建两苯环间乙烯桥,经四步反应、以Heek反应75.7%的收率和:50.3%的总收率合成了目标化合物(E)-3-甲氧基-4,4′-二羟基二苯乙烯(1),并对Heek反应等反应条件进行了探讨. 相似文献
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“4-苯基-2-咪唑啉酮的合成与表征”是“综合创新实验”课程的一个实验。该实验以苯甲醛和硝基甲烷为原料,经Henry反应、Ritter反应、硝基的还原、氨基的保护以及酰胺的水解反应,制备4-苯基-2-咪唑啉酮。实验涉及柱层析、加热回流和萃取等操作。该实验包括5种经典的反应类型,合成方法比较成熟,结合有机化合物波谱解析,可以加深学生理解有机化合物官能团的转化及经典反应的反应机理,培养和提高学生有机合成的实验能力,激发和训练学生对有机合成及波谱解析的理解和应用。 相似文献
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在三乙胺存在下,鉮盐与苯硫基氯化物反应,然后与醛反应,产生相应的α-苯硫基-α,β-不饱和羰基化合物,构型以(Z)-型为主,产率良好. 相似文献
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1,1-二溴-2-取代苯基乙烯是一种重要的有机合成中间体,该类化合物可以以芳醛为原料,通过Corey-Fuch法简便制备,并广泛应用于多取代烯烃、(E)-1-溴-2-取代苯基乙烯、芳炔、1,3-二炔(多炔)、芳炔溴化物和炔胺等化合物的合成。1,1-二溴-2-取代苯基乙烯中的(E)-Br和(Z)-Br存在明显的反应活性差异,因而适合于设计各种串联反应路线。近年来,利用其(E)-Br参与的Stille反应,Heck反应,Suzuki-Miyaura反应,Buchwald-Hartwig等各种偶联反应以及(Z)-Br和取代苯基邻位各种活性反应基团之间的环化反应,以1,1-二溴-2-取代苯基乙烯衍生物为底物合成了异香豆素类、茚类、吲哚类、异吲哚类、苯并噻吩和苯并呋喃类等多种具有重要生理活性或有合成价值的稠(杂)环化合物。本文从合成的化合物类别角度出发,对该领域近年来的研究进展进行了回顾和展望。 相似文献
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以2,4,5-三甲氧基苯甲醛为原料,利用Perkin反应,通过控制反应温度和丙酸酐的比例,使反应直接向生成α-细辛脑的方向进行,以提高反应收率和产品质量。对Perkin反应中影响产品收率和质量的投料比、反应温度和反应时间三个因素,设计了三水平三因素的正交试验,所得产品经熔点、有关物质检查、紫外分光光度法、红外光谱法、HPLC法确证。2,4,5-三甲氧基苯甲醛∶丙酸酐∶丙酸钠投料比为1∶1.2∶2.0,反应温度为210℃,反应时间7 h为最佳工艺,反应收率为65.8%,HPLC法测得α-细辛脑含量99.2%。经工艺条件优化后,以2,4,5-三甲氧基苯甲醛为原料,通过Perkin反应合成α-细辛脑的反应收率和产品质量显著提高,产品质量符合2015年版国家药品质量标准,可用于大规模工业化生产。 相似文献
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有机磷杂环化合物9,10-二氢-9-氧杂-10-膦杂菲-10-氧化物(DOPO)因性能优异而作为无卤阻燃剂得到广泛应用。为了提升和改进DOPO的合成,不少文献对合成中的4个反应,即酯化反应、酰基化反应、水解反应和关环反应进行了大量研究,但是由于缺少合适的分析方法和仪器,对酯化反应和酰基化反应仍没有得出明确的结论。本文则采用了核磁共振磷谱以及测量反应产物HCl吸收碱液的温度变化两种方法,精确地得到了酯化反应和酰基化反应的优化条件。首先采用核磁共振磷谱,讨论了酯化反应温度、原料配比和加料方式对酯化反应产物组成的影响,得出了邻苯基苯氧基二氯化磷(CC)含量高的工艺条件:反应温度80℃,PCl3过量25%~50%,采用邻苯基苯酚(OPP)加入PCl3的反滴法;并得出酯化反应产物的组成直接决定了6-氯-(6氢)-二苯并-(c,e)-氧磷杂己环(CDOP)在酰基化反应产物中的含量。另通过测量HCl吸收碱液的温度变化,间接表征酰基化反应的反应速度,由此得出合适的酰基化反应温度和催化剂用量。结果为:当催化剂固定为0.2 g时,酰基化反应在150℃几乎不反应,随温度升高,反应变快,180℃下4 h完全,190℃下1.5 h即可完成;温度180℃下,1~1.5 g/1 mol OPP的催化剂较为合适,酰基化反应在3~4 h结束。 相似文献
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从对苯二酚出发,经过两步反应合成了中间体化合物1,4-二(3-磺酸钠丙氧基)-2,5-二溴苯,再在Pd催化剂作用下,使1,4-二(3-磺酸钠丙氧基)-2,5-二溴苯与对二炔苯发生Sonogashira偶合反应,合成了目标共轭聚电解质PPE-SO3-,讨论了反应路线与反应条件的选择对聚合物合成的影响.PPE-SO3-主链具有刚性棒状结构,侧链带有离子基团,通过测量其在DMSO溶液中的粘度,研究了其溶液行为. 相似文献
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采用密度泛函理论(DFT)计算,研究了由1,4-环己二酮-2,5-二甲酸二甲酯(DMSS)制备2,5-二羟基对苯二甲酸(DHTA)的反应机理。其中,采用IEFPCM溶剂模型着重计算了DMSS由酮式互变异构为烯醇式的溶剂效应,并探究了碘在催化DMSS烯醇式氧化芳构化过程中的作用机制。计算结果表明,在溶剂分子的辅助下,DMSS酮-烯醇式互变异构反应的能垒显著降低;芳构化过程中,碘首先与过氧化氢反应生成活性物质次碘酸,其催化DMSS烯醇式发生碘代反应,并经过后续的消去和互变异构生成2,5-二羟基对苯二甲酸二甲酯(DMDHT),DMDHT进一步水解生成DHTA。同时,通过核磁共振氢谱测试验证了DMSS酮-烯醇式互变异构的溶剂效应;反应性能考评实验结果表明,相较于无催化剂,在碘的催化作用下,DMDHT产品的纯度和收率更高。 相似文献
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Pyrazine-2,5-dicarboxaldehyde was synthesized on a multi-gram scale by MnO2 oxidation of 2,5-bis(hydroxymethyl)pyrazine, which in turn was obtained from 2,5-dimethylpyrazine employing double Boekelheide reaction as a key step as reported previously. This reaction was subsequently utilized in a regioselective fashion as a key step to synthesize efficiently, for the first time, 3,6-di(long-chain)alkylpyrazine-2,5-dicarboxaldehydes starting from dl-alanine. These monomers are certain to have importance as electron deficient and chemically versatile components for new materials development. 相似文献
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Tiantian WangJia Liu Zhiliang LvHanyu Zhong Huan ChenChunjuan Niu Ke Li 《Tetrahedron》2011,67(19):3476-3482
An efficient and mild synthesis of highly substituted 2,5-dihydrofuran and furan derivatives from a variety of alkylidene malonates and 1,4-butyne-diol via one-pot reaction was applied. With various conditions of base amount, temperature and time applied to the reaction, the 2,5-dihydrofuran and the furan derivatives could be selectively obtained. Moreover, the formation of furan derivatives with 2,5-dihydrofuran derivatives as intermediates was also investigated. Some of these 2,5-dihydrofuran derivatives showed potent in vitro anti-tumor activities against HeLa cells. 相似文献
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Andrea C. Bruttomesso Javier Eiras Javier A. Ramírez Lydia R. Galagovsky 《Tetrahedron letters》2009,50(28):4022-4024
In this Letter we report that the Ugi reaction/cyclization sequence on a steroidal 17-carboxaldehyde leads to novel steroidal 2,5-diketopiperazines with a noteworthy stereoselectivity. A wide variety in the substitution pattern in the heterocyclic moiety was easily achieved by changing the components in the Ugi reaction. 相似文献
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Lithium perchlorate and acetic anhydride were the key additives for the multi-component reaction between 3-aminocyclohex-2-enones, formaldehyde, and malonates yielding adducts that were annulated under acidic conditions to afford bicyclic 2,5-dioxooctahydroquinoline-3-carboxylates. When methyl cyanoacetate was subjected to the same reaction conditions in the presence of a catalytic amount of triphenylphosphine, the bicyclic 2,5-dioxooctahydroquinoline-3-carbonitriles were obtained in a one-flask reaction. 相似文献
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Hiroyuki ShinoharaMotohiro Sonoda Shingo AtobeHaruna Masuno Akiya Ogawa 《Tetrahedron letters》2011,52(47):6238-6241
IrCl3·3H2O or FeCl3-catalyzed convenient synthesis of 3-hydroxyphthalates has been achieved by a Diels-Alder reaction of furans with dimethyl acetylenedicarboxylate, followed by ring-opening aromatization reaction of the Diels-Alder adducts, 7-oxabicyclo[2.2.1]hepta-2,5-diene derivatives. In addition, 7-azabicyclo[2.2.1]hepta-2,5-diene derivative, derived from N-Boc-pyrrole and dimethyl acetylenedicarboxylate, also converted into 3-aminophthalate derivative. 相似文献
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A Practical and Efficient Synthesis of 2,5-Disubstituted-3,5-dihydro-imidazol-4-ones from Oxazolones
An alternative procedure for the synthesis of 2,5-disubstituted-3,5-dihydro-imidazol-4-ones from substituted oxazolones was evaluated. The initial oxazolone ring-opening reaction was examined with a variety of ammonia source compounds followed by the subsequent 3,5-dihydro-imidazol-4-one cyclization reaction, which was carried out with either an organic or inorganic base in aprotic solvents. In this article, we report the results of an efficient and straightforward procedure for the synthesis of 2,5-disubstituted-3,5-dihydro-imidazol-4-ones that gives satisfactory yield and quality. 相似文献
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J. Gonzalo Rodriguez Jorge Esquivias Antonio Lafuente Laura Rubio 《Tetrahedron》2006,62(13):3112-3122
Nano conjugated thienylethenyl and thienylethynyl compounds with controlled structure and dimensions have been efficiently prepared, by heterocoupling reaction between 1,4-(thienylethynyl)phenylacetylene (or thienylethenyl)phenylacetylene and 2- or 2,5-dihalothiophene. Conjugated 1,4-di(2-thienylethynylphenyl)- (or 2-thienylethenylphenyl)-1,3-butadiyne were obtained by the homocoupling of the terminal acetylenes in excellent yield. The end-capped (N,N-dimethylaminophenyl)- and [3,5-di(trimethylsilylethynyl)-1-ethynyl]-2,5-di(phenylethynyl)nthiophene were obtained by the heterocoupling between the corresponding terminal acetylene and 2,5-di(iodo)thiophene, catalyzed by the bis(triphenylphosphine)palladium and cuprous iodide system in excellent yield. 相似文献