一种以聚酰亚胺为主链的分子刷合成及表征

以自制的侧基含溴的聚酰亚胺为大分子引发剂,2,2'-联吡啶/氯化亚铜为催化体系,通过原子转移自由基聚合(ATRP)反应,引发甲基丙烯酸三氟乙酯(TFEMA)和甲基丙烯酸2-(三甲基硅氧基)乙酯(HEMA-tms)共聚,制备了以聚酰亚胺为主链的分子刷,聚酰亚胺-接枝-聚(甲基丙烯酸三氟乙酯-共-甲基丙烯酸2-(三甲基硅氧基)乙酯),(PI-g-P(TFEMA-co-HEMA-tms)).对其中甲基丙烯酸2-(三甲基硅氧基)乙酯进行水解得到侧链含羟基的聚酰亚胺分子刷(PI-g-P(TFEMA-co-HEMA)),最后通过羟基与氯磷酸二乙酯反应,得到含亚磷酸酯基团的聚酰亚胺分子刷(PI-g-P(TFEMA-co-HEMA-P)).利用核磁共振氢谱(1H-NMR)、红外等方法,表征了所合成分子刷的结构.利用示差扫描量热法(DSC)、热失重分析(TGA)研究了聚合物分子刷的热性能.根据TGA计算出的分子刷组成与1H-NMR计算结果能较好的吻合.     

从磷硅试剂合成烃基膦酯类化合物

本文报导三甲基硅氧基亚磷酸酯(一种活性较高的磷硅试剂)与醛酮反应而获得十四个二乙基三甲硅氧基烃基膦酸酯。产物结构经IR,~1HNMR,~(31)PNMR,MS测试和元素分析表征;对反应机理作了初步讨论。     

新型含吡啶基的不对称膦酸酯衍生物的合成与生物活性

通过2-氯-5-氯甲基吡啶与亚磷酸酯的Michaelis-Becker反应合成得到10个新型含吡啶基的不对称膦酸酯衍生物, 并对环状亚磷酸酯与2-氯-5-氯甲基吡啶反应的立体化学进行了研究, 结果表明: 不对称环状亚磷酸酯的电子效应和立体效应对反应的立体化学有着重要影响. 初步的生物活性结果表明, 该类化合物不具有杀虫活性, 但显现出较好的杀菌活性.     

阻燃剂有机硅酸单环膦酸酯的合成与应用

以笼状亚磷酸酯4-乙基-2,6,7-三氧杂-1-磷杂双环[2.2.2]辛烷和甲基三甲氧基硅烷为原料,合成一种有机硅磷协同效应的阻燃剂,即有机硅酸单环膦酸酯(MSAMP)。探究不同物质的量比、反应温度以及反应时间对产率的影响,得出最佳反应条件:n(笼状亚磷酸酯):n(甲基三甲氧基硅烷)=1:1.2,在反应温度155℃的条件下反应17h,产品得率为87.5%。通过FTIR、~1H-NMR、TG-DTA对产物的结构及性能进行了表征,将产物应用于191不饱和树脂和PBT,通过极限氧指数法来测试其阻燃性能。结果表明,该产物具有较好的热稳定性及良好的阻燃效果。     

有机硅反应活性中间体的研究Ⅶ: 二(α-呋喃基)硅烯与烯烃加成反应的立体化学

硅烯是有机硅化学中一类基本的反应活性中间体.在研究硅烯与烯烃加成反应的立体化学过程中,我们曾研究了二苯基硅烯、苯基环丙基硅烯与烯加成反应的立体化学.近年来,Gaspar和Boudjouk分别报道了含大体积取代基的硅烯,如二金刚烷基硅烯、二叔丁基硅烯与烯烃的加成反应.我们从取代基的电子效应考虑曾研究了2-苯基-2-(a-噻吩基)六甲基三硅烷的光解,发现反应是自由基机理.氧和硫同属第Ⅵ主族,与噻吩相对应的含呋喃环三硅烷的光解又如何呢?因此,我们又设计并合成了二(α-呋喃基)硅烯的前体,2,2-二(α-呋喃基)六甲基三硅烷(1),并研究了这种硅烯与烯烃加成的立体化学.当1在光照下与trans-2-丁烯或cis-2-丁烯反应,所得硅杂环丙烷衍生物用甲醇开环时,得到了相同的2-丁基-二(α-呋喃基)甲氧基硅烷(3).     

三(硅烃基亚甲基)锡吡啶羧酸酯的研究

大多数三烃基锡化合物具有一定的生物活性,有一些已在农业生产中被用来作为杀虫剂、杀菌剂和杀螨剂使用.由于在它们的使用中出现较大的毒副作用,为此,人们合成了一系列含硅三烃基锡化合物,并对它们的生物活性进行了广泛的研究[1-3],结果表明,三[(三甲硅基)亚甲基]锡羧酸酯及其类似物具有较强的杀螨活性和广泛的生物活性谱,并且毒性有所减小.为了系统地研究含硅三烃基锡化合物,进一步探讨这类化合物的结构与生物活性之间的关系,本文用双[三(硅烃基亚甲基)锡]氧化物分别与三种不同的吡啶甲酸反应,合成了9个新的化合物三(硅烃基亚甲基)锡吡啶羧酸酯.反应方程式如下:     

聚γ-(m-二苯膦苯基)丙基硅氧烷——铂络合物对烯烃硅氢化反应的催化特征

本文报道二氧化硅负载的三苯膦铂络合物——聚γ-(m-二苯膦苯基)丙基硅氧烷铂络合物对三甲氧基硅烷与不饱和化合物进行硅氢加成反应的催化特性.在底物用量的万分之一摩尔量的铂络合物存在下,1-己烯、1-癸烯、1-十二碳烯、苯基烯丙醚和ω-氯代十一碳烯在60或40℃平稳地与三甲氧基硅烷发生硅氢加成反应,唯一地得到末端加成产物,产率均在85％以上.其催化活性在反应初期低于四(三苯膦)合铂,但后期反应速度和硅氢化产率均较高.实验表明,聚γ-(m-二苯膦苯基)丙基硅氧烷与四(三苯膦)合铂反应制得的铂络合物(1)比与氯铂酸反应制得的铂络合物(Ⅱ)催化活性高.其次,反应气氛对硅氢加成反应具有决定性的影响.在空气气氛中,硅氢化反应平稳地进行;在氮气气氛中,不发生反应.     

含次环己基的有机硅单体及其低聚体的合成

硅氯仿和环己二烯-1,3进行硅氢加成反应,生成1,3-双(三氯硅基)环己烷,经醇解制得1,3-双(三乙氧硅基)环己烷,与溴化甲基镁反应,制得1,3-双(二乙氧甲硅基)环己环、1-(乙氧二甲硅基)-3-(二乙氧甲硅基)环己烷和1,3-双(乙氧二甲硅基)环己烷,它们在盐酸溶液中分别进行水解,得到各种含次环己基的有机硅低聚体,其中2,2,4,4,11,11,13,13-八甲基-3,12-二氧(杂)-2,4,11,13-四硅(杂)三环[11,3,1,1~(5,9)]十八烷和D_4相似,可能经开环聚合得到聚硅次环己基硅氧烷。     

含硅二烃基锡羧酸酯的合成及抗癌活性

采用含硅二烃基锡氧化物和羧酸,以1∶2物质量的比进行反应,合成了5个新的有机锡化合物——含硅二烃基锡羧酸酯R(Me_3SiCH_2)SnL_2(R=Me_3SiCH_2或n-Bu,Cy;HL为1-金刚烷甲酸或N-乙酰甘氨酸)。通过IR、~1H NMR、~(13)C NMR和元素分析对它们的结构进行了表征;生物活性测定初步结果表明,它们对乳腺癌细胞MDA-MB-231具有较好的体外抗癌活性。     

含双(β-乙硫乙基)胺基配体的有机硅聚合物负载铂配合物的合成及其催化硅氢化性能

N,N—双(β—乙硫乙基)γ—(三乙氧硅基)丙胺单独或与十二烷基三乙氧基硅烷或与苯丙基三乙氧基硅烷共同以气相法二氧化硅固定化,再与氯亚铂酸钾反应,合成三种含双(β—乙硫乙基)胺基的高分子配体及其铂配合物。它们都是烯烃与三乙氧基硅烷的硅氢加成反应的有效催化剂。     

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.     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.