温度和pH敏感高分子含钆核磁共振成像造影剂的合成及性能

以N-异丙基丙烯酰胺为温度敏感单体,以甲基丙烯酸为p H敏感单体,与三丙烯酸菲洛啉钆进行无皂乳液聚合,一步合成了具有温度和pH敏感的高分子含钆核磁共振成像(MRI)造影剂(TPRPP).动态光散射测试结果表明,TPRPP的粒径随温度或p H值的变化而发生较大的改变.体外MRI测试结果表明,TPRPP的横向弛豫时间(T_1)的加权弛豫率约为11.3 L/(mmol·s),为临床造影剂Magnevist~的2.6倍.体内MRI结果表明,TPRPP在肝和脾中具有明显的正增强效果.研究结果表明,TPRPP是一种优异的多功能MRI造影剂,具有极大的临床研究价值.     

具有广谱紫外屏蔽性能的三元共聚物微球的制备

以醋酸乙烯酯(VA)、 马来酸酐(MA)和商品化的紫外吸收剂2-{2-羟基-5-[2-(甲基丙烯酰氧)乙基]苯基}-2H-苯并三唑(NB)为单体, 偶氮二异丁腈(AIBN)为引发剂, 通过自稳定沉淀聚合法(2SP)制备了具有广谱紫外屏蔽性能的单分散三元共聚物微球(PVMN); 研究了溶剂、 单体配比、 引发剂用量、 单体浓度、 反应温度和反应时间对共聚物微球形态和性能的影响. 研究结果表明, 体积比为7∶3的苯甲酸乙酯/正庚烷混合溶剂是2SP法合成单分散PVMN微球的理想溶剂. 随着单体配比中紫外吸收单体NB比例的增加, 引发剂用量、 单体浓度、 反应温度的提高和反应时间的延长, 微球的粒径随之增大, 进而改变了微球的紫外屏蔽性能. 本文制备的微球的粒径范围为(249±19)~(1434±213) nm, 优化得到的PVMN微球可屏蔽约90%的紫外光. 该策略还可扩展到其它可用作紫外吸收剂的乙烯基单体, 是一种制备稳定高分子紫外屏蔽剂的通用方法.     

可自去除模板法制备环境响应性PNIPAM空心微球

本文采用可自去除模板法制备了单分散的聚（N-异丙基丙烯酰胺） （PNIPAM）空心微球, 用透射电子显微镜（TEM）研究了不同工艺条件对微球尺寸和形貌的影响机制. 结果表明, 酸性单体甲基丙烯酸（MAA）的加入量决定了PNIPAM微球空腔的形成速度; 而MAA及表面活性剂十二烷基硫酸钠（SDS）的加入量对空心微球的粒径及空腔大小亦有明显影响. 具体地讲, 当MAA的浓度从1.06 mmol/L增加到4.24 mmol/L时, 空心微球的平均粒径从250 nm左右增加到约450 nm, 内部空腔尺寸从40 nm增加到270 nm; 而当SDS的浓度从0增加到0.62 mmol/L时, 空心微球的平均粒径及内部空腔尺寸分别从450和270 nm降低到320和130 nm. 紫外分光光度计和动态光散射的检测结果显示, 所得PNIPAM空心微球具有受pH控制的温度敏感性.     

大分子单体聚N-乙烯甲酰胺与苯乙烯共聚合成热敏性功能高分子微球

用自由基聚合法合成了大分子单体聚N 乙烯甲酰胺和功能高分子微球 .用GPC、分光光度仪和扫描电子显微镜等对合成的聚合物进行了表征 .研究结果表明 ,大分子单体聚N 乙烯甲酰胺和功能高分子微球具有明显的热敏性特性 ,且合成的功能高分子微球具有单分散性 ,粒径在 1～ 5 μm之间     

醇/水介质对PEG大分子单体与BMA分散共聚反应的影响

通过端基反应法合成了苯乙烯单封端的聚乙二醇(St- PEG)大分子单体,使其与甲基丙烯酸丁酯(BMA)在乙醇 水混合介质中进行分散共聚,得到了聚乙二醇接枝的聚甲基丙烯酸丁酯(PBMA- g -PEG)高分子微球.PBMA- g -PEG共聚物的亲溶剂 疏溶剂平衡将影响微球的形成,反应结束时,体系随BMA浓度和介质中水含量的变化呈现出4种不同的状态,透明清液、乳液、伴有沉淀或凝胶的乳液和凝胶.用透射电子显微镜(TEM)和激光光散射(LLS)对乳液体系的粒径及其形态进行了表征,表明所得接枝高分子微球形态规整具有较好的单分散性.通过控制介质中水的含量和BMA的浓度可得粒径在4 0～5 0 0nm范围的PBMA -g -PEG微球.     

超顺磁性高分子微球的制备与表征

用化学共沉淀方法制备了Fe3O4纳米微粒,并用油酸(十八烯酸)和十二烷基苯磺酸钠为双层表面活性剂进行表面修饰,制备了稳定的水分散性纳米Fe3O4可聚合磁流体.在Fe3O4磁流体存在下,将苯乙烯与甲基丙烯酸通过乳液聚合方法制备了磁性高分子微球.透射电镜研究表明,Fe3O4微粒的平均粒径在10nm左右,乳液聚合形成的磁性高分子微球的粒径平均约为130nm;用超导量子干涉仪对微粒及高分子微球进行了磁性表征,结果表明,合成的Fe3O4纳米微粒以及磁性高分子微球均具有超顺磁性.同时,还用红外光谱及X射线衍射表征了磁性高分子微球的化学成分和晶体结构.用热失重方法测得磁性高分子微球中磁性物质的含量为23.6%.     

含羧基磁性高分子微球的合成与表征

在共沉淀法合成超细磁粉的基础上，以苯乙烯(St)和丙烯酸为共聚单体，以过氧化苯甲酰(BPO)为引发剂，用分散聚合法得到了含羧基的具有核壳结构的磁性高分子微球。采用XRD、TEM、SEM、IR等对样品进行了表征。表征结果表明：制备的磁粉为Fe₃O₄单相，磁粉的粒径为10 nm左右，微球粒径大约在1～5 μm，呈球形，微球中存在羧基。VSM磁性能测试结果表明：用PEG4000作为表面活性剂时，样品的磁性能最强。分散剂和分散介质对微球形貌和粒度均有影响。     

高热稳定性聚膦腈亚微米球的室温快速合成

以六氯环三膦腈（HCCP）和4,4′-二羟基二苯砜（BPS）为共缩聚单体,乙腈为溶剂,三乙胺为缚酸剂,在室温条件下,采用沉淀聚合的方法快速合成了一种聚膦腈亚微米球。 红外光谱、元素分析及X射线能谱分析(EDX)测试表明,该聚膦腈亚微米球具有高度交联的化学结构;扫描电子显微镜和透射电子显微镜测试表明,该聚膦腈亚微米球粒径分布在410 nm附近,而且具有光滑的表面和实心的结构;热重分析(TGA)测试表明,该聚膦腈亚微米球的热分解温度达到531 ℃。 并推测了该聚膦腈亚微米球的形成机理。     

单分散磁性P(St/BA/MAA)微球的制备

在共沉淀法合成超细磁流体的基础上 ,以苯乙烯 (St)、丙烯酸丁酯 (BA)和甲基丙烯酸 (MAA)为共聚单体 ,在不同的介质体系中采用无皂乳液聚合法制备了单分散 ,粒径范围为 80～ 2 30nm的磁性P(St BA MAA)微球 .详细探讨了介质极性、磁流体中表面活性剂含量对磁性高分子微球粒径和单分散性的影响 .实验结果表明 ,在一定范围内随介质极性降低 ,磁性高分子微球的单分散性提高 ,随表面活性剂用量增加 ,单分散性变差 .总体来看 ,磁性高分子微球的单分散性与其表面静电斥力密切相关 ,过大或过小的静电斥力均会导致磁性高分子微球单分散性的降低 .     

相分离聚合法:(Ⅱ)二乙氨基乙基型共聚功能微球的合成

<正> 随着生物工程高技术的发展,功能高分子微球作为一类新的功能高分子材料已得到十分广泛的应用。然而关于最难以合成的粒径在微米级、粒度分布窄的高分子微球合成的报道至今仍很少。本文报道了用相分离法(即静止的分散聚合法)合成含有DEAE基团的高分子微球的研究。探讨了单体、交联剂、引发剂及聚合温度、聚合时间等聚合条件对生成微球的影响。相分离聚合法的特点是利用了随着在聚合过程中单体的逐渐聚合,分子量长大,聚合体与反应体系间相容性变差而最终分相成球的原理,因而所形成的微球粒度圆,粒径比较均一。与一般的分散聚合法相比不仅生成微球的粒径较大,且不需要搅拌,使反应装置得以简化。     

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.     

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.