二苯二硫和二苄二硫润滑性能的量子化学研究

The molecular geometries optimization and electronic structures of diphenyl disulfide (DPDS) and dibenzyl disulfide (DBDS) compounds were investigated by density functional theory (DFT) and ab initio method at the 6-31G basis set level. The active atoms and bonds of reaction were provided by frontier molecular orbital theory. The molecular orbital parameters of DPDS and DBDS compounds and iron atom cluster were calculated by using density functional theory. The interaction pattern between the organic disulfide compounds and iron atom cluster was discussed based on the approximate rule of orbital energy. Some parameters characterizing the action strength between the organic disulfide compounds and iron atom cluster, including the bonding strength, reactive strength and static action strength, were analyzed by using frontier electron density, super de-localizability, net atomic charge and the interaction energy of chemical adsorption as criteria. The results indicate that S-S chemical bond and C-S chemical bond of the compounds are inclined to be broken when DPDS and DBDS interact with the metal. The anti wear ability order of DPDS and DBDS compounds is DPDS>DBDS, and the extreme pressure ability order of DPDS and DBDS compounds is DBDS>DPDS, and the prediction results based on quantum chemistry calculations are in good accordance with the friction and wear test results.     

二苄基二茂钛的羰基化反应

用取代的二苄基二茂钛与一氧化碳在正庚烷中反应,生成二羰基二茂钛和二苄基甲酮。通过光谱监测,发现1摩尔一氧化碳插入碳钛键,得到取代的苯乙酰基苄基二茂钛。反应随着取代基给电子能力的增加而加快(Me>t-Bu≈H>F>Cl)。中间体Cp_2Ti[C(O)CH_2Ph]CH_2Ph很活泼,迅速发生分子内消除,消除的苄基和苯乙酰基生成二苄基酮。     

二苯甲烷二氨基甲酸酯的合成方法

综述了二苯甲烷二氨基甲酸酯的合成方法,讨论了合成二苯甲烷二氨基甲酸酯所涉及的甲基化试剂、催化剂。参考文献31篇。     

二苯甲烷二氨基甲酸甲酯热分解制备二苯甲烷二异氰酸酯的表观动力学研究

在癸二酸二(2-乙基己基)酯溶剂中研究了二苯甲烷二氨基甲酸甲酯(MDC)的分解反应机理,建立了二苯甲烷二氨基甲酸甲酯的分解反应动力学模型。通过实验测定,并对不同温度下体系中各物质的浓度数据进行线性拟合得到反应速率方程。结果表明：MDC的热分解分为两个步骤,均为一级反应。两步反应的活化能分别为：138.82kJ/mol,167.78kJ/mol;指前因子分别为：1.51×1012min-1,5.33×1014min-1。     

硝酸铁催化氧化二芳基乙醇酮制备二芳基乙二酮

用AcOH作溶剂,PEG400做相转移催化剂,硝酸铁能将二芳基乙醇酮催化氧化为二芳基乙二酮。产物结构用IR,MS和1H NMR光谱对其进行了表征。该方法有反应时间短,产率较高,操作简便等优点,是一种有效的由二芳基乙醇酮氧化制备二芳基乙二酮的方法。     

二苄基一氯化锡二硫代氨基甲酸酯的合成

二烃基氯化锡及其衍生物具有较强的抗癌活性，日益受到人们的重视。关于含有Ｓｎ—Ｏ键的二烃基锡衍生物的合成研究已有大量报道［１］。但含Ｓｎ—Ｓ键二烃基锡衍生物的合成研究则较少［２］，而二烃基一氯化锡二硫代氨基甲酸酯的合成研究尚未见报道。为了寻找具有抗癌活...     

二硫二磺酸掺杂聚苯胺电化学性能的研究

用聚有机二硫化物与聚苯质共混，是提高聚苯胺的电化学性能的有效方法之一．以二硫二磺酸为掺杂剂掺杂的聚苯胺,可明显地改善聚苯胺的电化学活性，使聚苯胶与掺杂剂中的－S－S－在相同的区域内共同参与氧化还原反应，提高了聚苯胺的电容量和充放电循环性．     

N,N''''-二芳基己二酰二肼类化合物的合成及其结构表征

报道了N,N'-二芳基己二酰二肼类化合物的合成方法.以自制的己二酰二氯、取代苯肼为原料,以二氯甲烷为溶剂,用冰浴法合成了9种新型的N,N'-二芳基己二酰二肼类化合物.产品的结构经元素分析、IR、1HNMR等测试技术得到确证,产物的IR谱中,在3200～3400 cm-1出现2个N-H吸收峰,1H NMR谱中,在δ7.3～10.5之间有2个N-H吸收峰,产品的元素分析结果与理论值基本相符.收率81%～93%.     

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.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

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.     

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.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.