Cu/SiO2催化剂上苯胺和正丙醇高效合成N-丙基苯胺

采用等体积浸渍法经程序升温焙烧制备了Cu/SiO2催化剂,考察了该催化剂对苯胺和正丙醇气相合成N-丙基苯胺的催化活性和选择性.常压下,当反应温度为260℃时,Cu/SiO2上正丙醇转化率达到100%,N-丙基苯胺选择性超过92%.X射线衍射分析表明,该催化剂具有较好的铜结晶度.     

邻溴苯胺/丙烯醛Schiff碱分子内Heck反应——合成喹啉的新方法

探讨了一种以邻溴苯胺和丙烯醛为原料合成喹啉的新方法,对反应条件进行了优化,并利用质谱和红外光谱分析确认了合成产物的结构.结果表明,以邻溴苯胺和丙烯醛为原料,经2步反应可得到喹啉:首先,邻溴苯胺和丙烯醛反应生成Schiff碱;随后,Schiff碱在催化剂和N2保护下经分子内Heck反应形成目标产物(总产率为45.1%).该合成方法具有操作简单、易于控制、催化剂可重复使用等优点.     

常压催化合成N-乙基间甲氧基苯胺

以间氨苯酚为原料,用溴乙烷做烷基化试剂,硫酸二甲酯作甲基化试剂,通过改变溶剂及加入合适的相转移催化剂等方法优化工艺,经两步反应合成N-乙基间甲氧基苯胺,产率达到48.8%。该反应步骤少,原料廉价易得,反应条件极其温和,方法简单,为实际生产提供了依据。     

4-硝基二苯胺和4-亚硝基二苯胺钠催化加氢制4-氨基二苯胺 Ⅰ.溶剂对加氢反应的影响

用Pd—M/C催化剂(M为非贵金属),对工业原料4-硝基二苯胺及4-亚硝基二苯胺钠催化加氢制4-氨基二苯胺,其活性和选择性都较好。本文报导了在常压加氢中添加各种溶剂对反应的影响,并建议采用苯胺溶剂较适宜。     

空气下无配体钯催化二苯胺和卤代芳烃的C—N偶联

研究了空气下无配体Pd(OAc)2在弱碱碳酸钾存在下催化二苯胺和溴代芳烃的C—N偶联合成三苯胺类化合物.与传统合成方法相比,该反应可以在无配体存在下在空气和温和的条件下进行,即,无需无水无氧操作条件,操作特别方便.催化剂用量、碱、溶剂、反应温度、反应时间等因素对反应的影响均做了考察.优化的反应条件是:在Pd(OAc)2(3 mol%)和K2CO3(1.5 equiv.)存在下,二苯胺和溴代芳烃在DMSO中在空气下在90℃加热24 h.溴代芳烃上的吸电子基团和二苯胺上的给电子基团有利于该偶联反应的进行,其中4-硝基三苯胺的产率高达93%.     

气相法苯胺N—烷基化反应研究：Ⅲ.苯胺和甲醇催化合成N,N—二甲…

本文报导了在系列复合氧化物催化剂上苯胺和甲醇反应合成Ｎ，Ｎ－二甲苯胺研究，并从中选择了活性和选择性良好的ＬＨＰ催化剂，在常压气相反应条件下说细地考察了反应温度，液时空速，苯胺和甲醇摩尔比变化等对催化剂活性和选择性的影响，提出了两段转化的新工艺流程。     

电催化活化二氧化碳合成苯氨基甲酸乙酯

在常温常压下,通过循环伏安法探讨了Ni(bpy)3Cl2催化剂对CO2间接电化学活化的机理及CO2与苯胺、碘乙烷合成苯氨基甲酸乙酯的反应机理.结果表明,Ni(bpy)3Cl2催化剂对CO2的活化具有很高的催化效率,DMF溶液中加入Ni(bpy)3Cl2催化剂可使CO2的电化学还原电位由-2.3V移到-1.6V,从而可大大改善合成苯氨基甲酸乙酯反应的条件,苯氨基甲酸乙酯的选择性可达100%.考察了催化剂用量、电解电位、工作电极材料、温度和支持电解质及通电量对苯氨基甲酸乙酯收率的影响.结果表明,在优化的条件下,苯氨基甲酸乙酯的收率为60.8%.     

4,4'-二氨基三苯胺的合成与纯化

以苯胺和对硝基氯苯为原料,K2CO3作催化剂,合成出了中间产物4,4'-二硝基三苯胺(DNTPA).将中间产物用10%(质量分数)的Pd/C催化剂加氢催化还原,得到纯度为96.6%的目标产物4,4'-二氨基三苯胺(DATPA),合成总产率为38%.与其它方法相比,该方法原料便宜易得,纯度很高,产物可作为反应的单体原料.     

4,4'-二氨基三苯胺的合成与纯化

以苯胺和对硝基氯苯为原料, K₂CO₃作催化剂, 合成出了中间产物4,4'-二硝基三苯胺(DNTPA). 将中间产物用10%(质量分数)的Pd/C催化剂加氢催化还原, 得到纯度为96.6%的目标产物4,4'-二氨基三苯胺(DATPA), 合成总产率为38%. 与其它方法相比, 该方法原料便宜易得, 纯度很高, 产物可作为反应的单体原料.     

气相法苯胺N-烷基化反应研究Ⅲ.苯胺和甲醇催化合成N,N-二甲基苯胺研究

本文报导了在系列复合氧化物催化剂上苯胺和甲醇反应合成Ｎ，Ｎ－二甲苯胺（ＤＭＡ）研究，并从中选择了活性和选择性都良好的ＬＨＰ催化剂，在常压气相反应条件下详细地考察了反应温度，液时空速（ＬＨＳＶ），苯胺和甲醇摩尔比变化等对催化剂活性和选择性的影响，提出了两段转化的新工艺流程。并经扩大试验，证明两段转化工艺过程优于一段转化法。第一段反应时苯胺转化率大于９５％，ＤＭＡ选择性大于７０％，第二段转化后，产物中几乎不含苯胺，ＤＭＡ选择性大于９４％，并在工业固定床催化反应装置中常压气相反应条件下试生产成功。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.