共查询到20条相似文献,搜索用时 171 毫秒
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以醛、吲哚和麦氏酸为原料,水和乙醇混合液为溶剂,在室温搅拌条件下以磷酸二氢钾为催化剂通过Yonemitsu缩合反应,合成了一系列的5-[(3-吲哚基)-芳甲基]-2,2-二甲基-1,3-二噁烷-4,6-二酮衍生物,产率为48%~98%,并通过X射线单晶衍射仪测定了化合物4o的晶体结构。 该方法能够有效的促使反应活性较低的4-甲基苯甲醛和4-甲氧基苯甲醛参与反应,以83%和60%的收率获得相应的目标产物,并具有反应条件温和、催化剂廉价易得、后处理简单、产物易于纯化、产率较高等优点,可用于合成3-取代吲哚类化合物。 相似文献
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近两年来,关于自由基加成/关环反应合成1,3-二氢吲哚-2-酮的报道屡见不鲜.它们大多以N-芳基取代的丙烯酰胺类化合物为底物,在各种不同的金属、无金属和光的催化作用下,与不同的自由基反应,可以一步生成3,3-二取代的吲哚-2-酮衍生物.该类方法现已成为合成含氮五元杂环的一个重要手段,用来合成1,3-二氢吲哚-2-酮及其衍生物.目前对自由基加成/关环反应合成该类化合物的研究多集中在不同催化手段引发不同的自由基和反应机理上.按催化剂类型的不同,对近年来自由基加成/关环反应合成吲哚-2-酮的研究进展进行了综述. 相似文献
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B. Jeowska-Trzebiatowska H. Kozowski L. Latos-Grayski T. Kowalik 《Chemical physics letters》1975,30(3):355-357
The complexes Zn(bipy)Cl2 and Zn(bipy)2Cl2 as well as 2,2′-bipyridyl in aqueous solution (D2O) have been examined by the NMR method. The presence of the monocationic bipy D+ form in aqueous bipyridyl solution has been found. The changes of chemical shifts of bipyridyl protons for complexes Zn(bipy)3Cl2 and Zn(bipy)Cl2 have confirmed explicitly the essential influence of diamagnetic currents on the NMR spectrum of Zn(bipy)3Cl2. The comparison of the spectra of 2,2′-bipyridyl (in CH3OH) and of Zn(bipy)Cl2 may also suggest the presence of the nonbonding metal-proton 6 interaction. 相似文献
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The reaction of 2,2-bis(dimethylamino)-3,3-difluoro-1-methylcyclobutane-carbonitrile with alkyl lithiums leads to the formation of 6-alkyl-2-(dimethylamino)-3-fluoro-5-methylpyridines in moderate to good yields. 相似文献
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A series of 2,2-difluoro-2H-chromenes were synthesized from the tandem reactions of ethyl 3-bromo-3,3-difluoropropionate with salicylaldehyde derivatives in good yields under basic conditions. In acidic environment defluorination took place during the reaction. A plausible mechanism was proposed based on the experimental results. 相似文献
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研究了一种新的铱催化的Morita-Baylis-Hillman(MBH)乙酸酯与3-苯基取代的吲哚酮的烯丙基烷基化反应,发现铱催化的区域选择明显不同于钯催化的反应,直接、高效地合成了一类未见报道的具有新结构的3,3-二取代的吲哚酮类化合物.通过对亚磷酰胺、双膦及单膦等配体、金属源、溶剂、碱以及反应温度的筛选,获得了适合该反应的催化体系及最优条件:以[Ir(COD)Cl]2(摩尔分数5%)和亚磷酰胺配体(L6,摩尔分数10%)为催化剂, CH3CN为溶剂, Cs2CO3为碱,于-30℃反应25 h.在最优条件下,对不同类型取代基的底物进行了考察,发现底物普适性良好,产率最低为84%,最高可达98%.同时还发现,底物取代基的电性对反应产率影响不大,一些其它类型的双膦和单膦配体对催化反应也有较好的催化效果. 相似文献
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在三氟甲磺酸银的催化下,二苯二硒醚被1-氯甲基-4-氟-1,4-二氮杂双环[2.2.2]辛烷二(四氟硼酸盐)(Selectfluor)氧化后,分别与1-己烯烃、苯乙烯或其衍生物加成;在含有水或醇(如甲醇、乙醇、异丙醇)的二氯甲烷中(二氯甲烷与水或醇的体积比为1∶1)反应,分别得到β-羟基或β-烷氧基苯硒醚,产率为72%~94%;探讨了反应条件及底物的适用范围。此方法具有反应条件温和、产率高的特点。 相似文献
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Xuejian Li Bangzhong Wang Dr. Dong Li Dr. Jinfeng Zhao Prof. Dr. Jingping Qu Prof. Dr. Yuhan Zhou 《European journal of organic chemistry》2023,26(15):e202201452
An efficient and environmentally friendly methodology for 3,3-dichlorination and 2-oxidation of indole derivatives is described. Using KI as promotor, MCl (M=K, Na) as chlorine source, and oxone as oxidant, the reaction proceeds smoothly affording various functionalized 3,3-dichloro-2-oxindoles in moderate to excellent yields. This strategy can also be extended to 3-substituted indoles. With a broad substrate scope, it is a practical approach to 3,3-disubstituted-2-oxindoles. 相似文献
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Aitor Ortega-Martínez Rocco de Lorenzo José M. Sansano Carmen Nájera 《Tetrahedron》2018,74(2):253-259
The Pd-catalyzed allylation of 3-acetyl-2-oxindoles with allyl alcohol is performed using 3 mol% of Pd(dba)2, rac-BINAP and BINOL phosphoric acid as catalytic mixture. This procedure allows the in situ synthesis of 3-allyl-2-oxindole by adding Triton B to the reaction mixture. The deacylative allylation of 3-acetyl-3-methyl-2-oxindoles with allylic alcohols is carried out with 3 mol% of Pd(OAc)2, dppp and 1.5 equiv. of LiOtBu as base affording the corresponding 3,3-disubstituted 2-oxindoles in good yields. Both methodologies can be combined for the preparation of unsymmetrical 3,3-diallylated 2-oxindoles such as compound 7. The DaA must be carried out in the absence of oxygen in order to avoid the competitive formation of 3-alkyl-3-hydroxy-2-indoles. The later compounds can be easily obtained by deacylative oxidation of 3-alkylated 3-acetyl-2-oxindoles with LiOEt at rt under air. 相似文献
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醋酸钯和四氯对苯醌催化氧化低浓度煤矿瓦斯制甲醇 《燃料化学学报》2016,44(2):239-243
利用自制的实验系统进行了醋酸溶液中低浓度瓦斯催化氧化制甲醇研究。实验结果表明,以Pd(OAc)2为催化剂,反应体系中添加对苯醌或四氯对苯醌可改善甲烷活化环境,四氯对苯醌对瓦斯催化氧化过程的作用效果好于对苯醌。四氯对苯醌用量、反应压力和反应温度对瓦斯催化氧化具有重要影响。甲醇生成量随四氯对苯醌用量、反应压力和反应温度升高而增加。CH3OH是通过反应过程中产生的H2O2与CH4相互作用形成的。CH3COOCH3一部分是由Pd2+直接氧化CH4得到的;另一部分是由CH3OH与反应溶剂CH3COOH通过酯化反应形成的。 相似文献
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The transition metal-catalyzed direct activation of electron deficient triple bonds was investigated by using the combined electron withdrawing effects of two fluorine atoms to modulate the electronic density of the triple bond. With use of catalytic amounts of AgNO3 (10 mol %) the synthesis of substituted 3,3-difluoro-4,5-dihydrofurans from gem-difluorohomopropargyl alcohols occurred in excellent NMR yields. Treatment of these dihydrofurans with SiO2 or Pd/H2 yielded the corresponding 3-fluorinated furans and 3,3-difluorotetrahydrofurans. 相似文献
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The complexes (O---O)Rh(CH2CH2)2 ((O---OH) = FcC(O)CH2C(O)CH3, PhC(O)CH2C(O)CH3, 1,2-(CH3CO)(OH)C6H4, 3-benzoyl-(+)-camphor) are catalysts for the hydrosilylation of PhMeCO with Ph2SiH2. The optical yield from the reaction catalyzed by the camphor derivative is too low to measure. Only low optical yields (max 8.7% e.e.) are obtained from the same reaction by using similar in situ catalysts with ligands prepared from (+)-PhCH(Me)NH2. Bases such as H− and PhCH(Me)NH− catalyze the hydrosilylation reaction in the absence of rhodium salts, but only low optical yields are obtained. Ph2SiH2 reacts with 2-cyclohexen-1-one under these conditions and the mode of reaction depends on the reaction conditions. 相似文献