μ-氧代双锰卟啉催化下空气高选择氧化乙苯

金属卟啉能够在温和条件下催化烃类的部分氧化,且有较好的选择性因此,金属卟啉的仿生催化研究不仅具有重大的理论意义,亦有广阔的应用前景,现已成为仿生催化领域中人们极感兴趣的工作,但是,金属卟啉化合物催化领域中人们极感举的工作,但是,金属卟啉化合物催化烃类氧化时,一般须使用诸如PhIO、NaClO、H2O2这样的单氧原子供体作氧化剂,或使用诸如锌粉、Vc等还原剂加分子氧体系,从实际应用来看,单独使用分子氧为氧化剂用于金属卟啉催化烃类氧化是最具诱惑力的。然而,在这方面的研究报导仅见于多卤代卟啉,我们在探索单独用空气作用氧化剂进行金属卟啉仿生催化时发现,象乙苯这样含有相对较为活泼的C－H键的分子,在μ－氧化双锰卟啉（[TPPMn]2O)的催化下,亦能够直接被分子氧氧化,本工作考察了各种因素对该反应的影响。     

金属酞菁与高价金属盐或氧化物在乙苯液相催化氧化反应中的协同效应

金属络合物催化饱和烷烃的选择性催化氧化一直是有机合成中具有挑战性的课题之一.饱和烷烃的催化氧化可采用各种氧源,如PhIO、H2O2、有机过氧化物或次氯酸盐等[1,2],然而采用分子氧为氧源对烃类化合物进行选择性催化氧化一直是人们致力于解决的目标.利用分子氧为氧源实现饱和烷烃的选择性催化氧化大致可分为两条路线:(1)在共还原剂(H2,醛,抗坏血酸)存在下利用原位产生的氧化剂的催化氧化[3,4];(2)金属卟啉[5]、杂多酸[6]及其它催化剂对饱和烷烃的直接催化氧化.路线(1)需要消耗大量的共还原剂,实际上是对分子氧的间接利用,不具有明显的实…     

非质子介质中氧电还原的研究：Ⅲ.金属卟啉电催化氧还原及反应的研究

金属卟啉化合物在生物领域中的作用引起了人们的广泛注意.尤其是其催化作用以及电子转移方面已有很多报道.在催化方面大多数是利用氧化剂把中心离子氧化成高价态,而利用卟啉低价态进行催化方面的研究报道还很少。在这一方面我们已经做了一些工作,氧电还原产生的超氧离子[O_2~÷]虽能参与许多有机反应,如亲核取代,环氧化,氧     

Ag-TiO2纳米催化剂的制备、表征及环氧化催化性能

环氧化合物是一类重要的有机合成中间体。工业上环氧乙烷是以Ａｇ ＳｒＯ ＣａＯ作催化剂 ,通过多相催化由乙烯和氧气氧化得到 ,其它的Ｃ2以上烯烃不能用该法生产 ,因为反应温度高 ,选择性很差。高温下的银催化乙烯的分子氧环氧化 ,选择性高于 80 % ,而用于丙烯的环氧化时 ,选择性大大降低[1] ,银多相催化分子氧环氧化烯烃的研究较活跃[2 5] 。本文合成了Ａｇ ＴｉＯ2 纳米催化剂 ,对其进行了表征 ,并初步研究了其环氧化催化性能。1　实验部分1 .1　仪器药品ＴｅｓｔｓｃａｎＳｈｉｍａｄｚｕＦＴＩＲ 80 0 0ｓｅｒｉｅｓ红外光谱仪 (ＫＢ…     

N-羟基-N-苯基-2-吡啶甲酰胺钴配合物的合成及均相催化乙苯的氧化反应

近年来,在催化氧化反应领域,人们一直试图用价廉易得的氧作氧化剂,在较温和的条件下催化烃类氧化,以得到价值更高的含氧化合物．研究新的活化分子氧的高活性催化剂成为化学家追求的重要目标之一［１～４］．在各类催化剂中,金属卟啉类［５,６］和金属席夫碱类［...     

己二酸绿色合成新途径

己二酸是合成纤维的重要原料 .己二酸的工业生产过程大都采用环己酮和环己醇的硝酸氧化法 ,因而造成了严重的环境问题 .尽管可对Ｎ2 Ｏ进行有效的回收和利用[1],但其年排放量仍达到 4 0万吨[2 ].因此 ,增加化学反应过程的选择性 ,最大限度利用初始原料 ,用催化剂代替传统工业上使用的有毒或有腐蚀性的化学计量反应试剂以及使最终反应产物更加容易分离是绿色合成技术的主要目标[3].烃类选择性氧化的传统氧化剂为Ｋ2 Ｃｒ2 Ｏ7,ＫＭｎＯ4,ＨＮＯ3,ＮａＯＣｌ等 ,该类氧化剂已逐步被清洁氧化剂所取代[4 9].Ｎｏｙｏｒｉ等[10 ]以Ｎａ2 ＷＯ4·2…     

离子液体体系中氯化金属卟啉对苯甲醇的催化氧化反应

研究了一种将苯甲醇直接氧化成苯甲醛的催化体系:氯化金属卟啉/离子液体/氧化剂(MTPPCl/ILs/[O]),考察了该体系反应过程中温度、氯化金属卟啉、氧化剂、轴向配体和离子液体的种类等因素对反应收率的影响。结果表明,催化剂氯化锰卟啉、溶剂1-丁基-3-甲基咪唑硫酸氢盐离子液体、氧化剂过硫酸钾组成的催化体系MnTPPCl/[Bmim]HSO4/K2S2O8在苯甲醇直接催化氧化成苯甲醛的反应中表现出很好的活性(99%)和选择性(99%),且该体系避免了使用传统的有机溶剂,可重复多次使用。     

CoPc/Al2O3催化分子氧环氧化环己烯的研究

常使用均相催化剂[1-4]催化氧化剂对烯烃进行环氧化来制备环氧环己烷,但均相催化剂存在分离回收难,易二聚失活的缺点.近年来对均相催化剂的固载开展了广泛的研究,如郑岩等[5]使用溶胶 -凝胶包容乙酰丙酮镍,M.Salavati-Niasari等[6]用Al2O3固载Mn(Salen)、Mn(en)2和Mn(acac)2金属配合物用于烯烃环氧化,由于Al2O3廉价易得,酞菁具有不易二聚、降解等较稳定的优点[3],本文以酸性Al2O3为载体,固载酞菁钴金属配合物制备CoPc/Al2O3新型环氧化催化剂,并对其结构进行表征,同时以分子氧为氧源,异丁醛为还原剂考察CoPc/Al2O3催化剂对环己烯的催化环氧化活性,探索了环己烯环氧化的较佳工艺参数.     

聚合物键合Cu（Salen）的合成及其催化作用

一些简单的无机配合物已经广泛地用作氧载体和氧化催化剂,其中研究较多的是过渡金属卟啉和席夫碱（Schiff base）－过渡金属配合物。其中,席夫碱－过渡金属配合物的合成简单、易于控制配体的电子与立体因素,因而其催化性能的调变更具有灵活性,其分子氧体系已用于烯烃的环氧化和醇类的氧化,卟啉钴配合物－分子氧体系对硫醇的催化氧化研究已报道,其于席夫碱－金属配合物具有结合分子氧的特性和催经作用,以及高分子配合物催化剂的特点,我们合成了聚合物键合双水扬醛缩乙二胺合铜（Ⅱ）,并将其用于催化分子氧氧化丙硫醇转化成二硫化物。     

MCM-41固载Co席夫碱配合物的制备及其催化烯烃环氧化的研究

环氧化合物作为有机合成中间体具有广泛应用,催化烯烃环氧化一直是催化化学中的一个重要课题[1～2].尽管已经报道了以过酸、过氧化氢、烷基过氧化物、或分子氧为氧化剂,以金属配合物(通常为钌、钼、钛的配合物)为催化剂的反应体系,但对环氧化物的选择性却很低[3].另外,除了需探索具有高选择性的催化体系外,应用分子氧或空气作为氧化剂更适宜于经济和安全的要求.目前,在以分子氧作为氧化剂,均相催化烯烃环氧化的研究中,应用醛类化合物作为氧转移试剂是一种有效的和方便的促进烯烃环氧化的方法[4].但是,均相催化剂难于分离和重复使用,因此…     

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%.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.