新型芳香胺－邻醌聚合物的合成及其作为纳料固定化酶载体的研究

以碘酸盐为氧化剂，通过氧化－迈克尔加成反应，由邻苯二酚和4,4'-亚甲基 苯胺合成了一种新的功能聚合物，芳香胺－邻醌聚合物。这种聚合物表面由分布均 匀的纳料颗粒和孔穴构成。由于这种聚合物分子含有疏水骨架、羰基和胺基的有序 分布，以及独特的纳料微观颗粒和孔穴结构，使其成为吸附法固定化酶的良好载 体。     

苯甲酸乙烯酯与受电子的可逆加成－断链链转移共聚合

采用二硫代苯甲酸苄酯和偶氮二异丁腈组成的引发体系,以可逆加成－断链链 转移聚合方法合成了苯甲酸乙烯酯与马来酸酐及N－取代马来酰亚胺的交替共聚物 。结果表明,所行聚合物具有预期分子量,分子量分布在1.1～1.3之间。在较低转 化率下所得的聚合物均为交替结构,而与摩尔设料比无关。     

苯甲酸乙烯酯与受电子的可逆加成－断链链转移共聚合

采用二硫代苯甲酸苄酯和偶氮二异丁腈组成的引发体系，以可逆加成－断链链 转移聚合方法合成了苯甲酸乙烯酯与马来酸酐及N－取代马来酰亚胺的交替共聚物 。结果表明，所行聚合物具有预期分子量，分子量分布在1.1～1.3之间。在较低转 化率下所得的聚合物均为交替结构，而与摩尔设料比无关。     

烷基硫酸钠中碳链长度分布对MMA种子乳液聚合粒径分布影响的研究

氯磺酸法合成了C8－10、C12和C14－16烷基硫酸钠，精制后表征了碳链分布组成，在C12为30％－80％范围内研究了烷基硫酸钠中高碳同系物和低碳同系物的比例对甲基丙烯酸甲酯种子乳液聚合生成的聚合物粒径大小和分布的影响，并讨论了成核模式。研究结果表明：高碳同系物比例的增加，聚合物平均粒径增大，低碳同系物比例的增加，胶束数目增多，由胶束成核（包括均相成核）而形成的聚合物粒径分布变宽，而对在种子上增长的聚合物粒径分布无影响。     

纳米颗粒增强的葡萄糖生物传感器

研制的纳米增强葡萄糖传感器是用纳米憎水Ａｕ颗粒。亲水Ａｕ颗粒、憎水ＳｉＯ_２颗粒以及Ａｕ和－ＳｉＯ_2颗粒混合与聚乙烯醇缩丁醛（ＰＶＢ）构成复合固酶膜基质,用溶胶－凝胶法固定葡萄糖氧化酶（ＧＯＤ）,组成葡萄糖生物传感器．实验表明,纳米颗粒可以大幅度提高固定化酶的催化活性,响应电流从相应浓度的几十纳安增强到几千纳安,电极响应迅速, １ｍｉｎ达到稳态,探讨了纳米颗粒效应在固定化酶中所起的作用,开辟了制备直接电子传递第三代生物传感器的新途径和纳米颗粒应用的新领域。     

AB2型聚合物流体的表面结构性质

在密度泛函理论(DFT)框架下, 应用改进的基本度量理论(MFMT)表达硬球作用对自由能泛函的贡献, 根据统计力学理论结合加权密度近似(WDA)表达聚合作用对自由能泛函的贡献, 建立了描述AB2型聚合物流体的化学势, 得到了聚合物流体在硬球颗粒表面的密度分布表达式, 计算了聚合物流体在硬球颗粒表面附近的密度分布, 并探讨了体积分数、聚合程度和硬球颗粒尺度对体系密度分布的影响. 此外, 通过体系密度分布, 进一步分析了体积分数、聚合程度和硬球颗粒尺度与剩余吸附的关系.     

激光CVD法合成SiC-Si3N4复合纳米颗粒

用激光化学蒸汽沉积(CVD)法合成了SiC-Si₃N₄复合纳米颗粒,并用X射线衍射(XRD),透射电子显微镜(TEM)和电子自旋共振磁力计(ESR)分析了试料的晶体结构,颗粒形状以及悬空键的状况。合成的试料粒度分布集中,平均粒径为32nm,颗粒由直径为5～30nm的单晶或多晶组成。试料纯度高,颗粒为近似球形,十分适合于粉体的加工和烧结。另外试料有很高的热稳定性,在加热的过程中的变化首先是悬空键减少,然后是相分解和颗粒长大。     

不同干燥过程对超细TiO2粉体性质的影响

考察了采用不同干燥工艺制备的TiO2粉体在粒子形貌、颗粒大小与分布、晶相组成以及比表面积和孔结构等织构和结构性质方面的差异。结果表明，利用常规的干燥方法，由水凝胶脱水所得的颗粒，颗粒间严重团聚，颗粒粒径大且分布不均匀，比表面积和孔体积最小；由醇凝胶直接脱水，则可以显著提高粉体的织构性能．而采用超临界流体干燥法则可以进一步提高粉体的性能，比表面积由水凝胶的4．88m2·g－1增大到113．8m2·g－1，提高了近30倍；孔体积由0．027cm3·g－1增大到0．41cm3·g-1．大约提高了15倍；而且其能够有效地防止粒子间的团聚，较好地保持了湿凝胶的网络结构，使颗粒尺寸降低且分布均匀，可重复性好．     

识别三唑类农药的片段印迹聚合物的合成及在固相萃取中的应用

采用片段印迹技术, 合成了一系列对7种三唑类农药(三唑酮、烯唑醇、多效唑、烯效唑、戊唑醇、三唑醇和双苯三唑醇)具有识别能力的聚合物. 振荡平衡吸附实验表明, 以邻硝基苯酚为模板的聚合物(M1)对上述7种农药具有最佳的选择性吸附性能. 根据分析物结构对片段印迹聚合物吸附能力的影响, 提出了片段印迹聚合物的识别机理: 三唑类化合物的分子片段末端苯环进入片段印迹聚合物的孔穴中, 同时其羟基与聚合物孔穴外的功能单体4-乙烯基吡啶上的氮原子形成氢键, 二者的协同作用实现对目标分子的选择性识别, 其中分析物末端苯环和聚合物孔穴的匹配是影响片段聚合物识别能力的主要因素. 将基质固相分散(MSPD)与以M1为吸附剂的分子印迹固相萃取(MISPE)联用, 用于土壤样品的前处理. 在3种添加水平下, 各分析物的回收率均为75%~102%, 相对标准偏差为3%~9%(n=5), 方法检出限(信噪比等于3)0.9~15 μg/kg. 表明该分析方法结合了MSPD的快速提取和MISPE的高选择性的特点.     

超细银－金复合颗粒增强酶生物传感器的研究

用琥珀酸二异辛酯磺酸钠／环已烷反胶束体系合成憎水纳米银－金复合颗粒， 并用此纳米银－金颗粒与聚乙烯醇缩丁醛构成复合固酶模基质，用溶胶－凝胶法固 定葡萄糖氧化酶，构建葡萄糖生物传感器。实验表明，纳米憎水银－金颗粒可以大 幅度提高固定化酶的催化活性，响应电流从相应浓度的几十纳安增强几万纳安。探 讨了纳米颗粒效应在固定化酶中所起的作用，为纳米颗粒在生物传感器领域中的应 用提供了可参考的实验和理论依据。     

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.     

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%).     

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.     

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.