异戊巴比妥分子印迹聚合物的合成和识别性能研究

以异戊巴比妥为模板,分别以丙烯酰胺和甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,用本体聚合法制备了分子印迹聚合物(molecularly imprinted polymer,MIP)。考察了以不同功能单体合成的MIP对模板分子和结构类似物的识别能力和选择性。表明以丙烯酰胺为功能单体合成得到的MIP比甲基丙烯酸为单体的聚合物具有更好的再识别性和选择性,前者对异戊巴比妥的饱和吸附量可达到28．58μmol／g．为理论吸附量的40．9％。     

3-吲哚乙酸印迹聚合物的制备及其分子识别性能

以IAA为模板分子,4-乙烯基吡啶(4-Vpy)为功能单体,乙腈为致孔剂,采用本体聚合方法,制备了IAA的印迹聚合物P(4-Vpy),用色谱法评价了其分子识别性能,并且与同样条件下以丙烯酰胺(AA)为功能单体合成的IAA印迹聚合物P(AA)进行了比较。结果表明,乙腈为流动相时,P(4-Vpy)比P(AA)对IAA具有更高的印迹效率,对IAA表现出了更好的分子识别能力。流动相对P(4-Vpy)分子识别能力的影响实验证明,静电作用在其分子识别过程中起重要作用。两种不同用量的乙腈为致孔剂制备所得IAA印迹聚合物P(4-Vpy)和P`(4-Vpy)的色谱测定结果表明,致孔剂的加入量对其印迹效率有显著影响。     

对羟基苯甲酸、水杨酸分子印迹聚合物分子识别性质的 研究

以对羟基苯甲酸(4-HBA)为模板分子,4-乙烯吡啶(4-Vpy)为功能单体,制备得到了4-HBA分子印迹聚合物P(4-HBA),研究了该聚合物的分子识别机理,并与在同样条件下制备的水杨酸(SA)分子印迹聚合物P(SA)进行了分子识别能力的比较。结果表明：P(SA)比P(4-HBA)具有更好的分子识别能力。这是由于SA的酸性较4-HBA强,因此与碱性功能单体4-Vpy之间的静电作用更强,从而得到的复合物更稳定。本实验结果证明：功能单体与模板分子形成稳定的复合物是得到分子识别能力高的模板聚合物的前提条件。本文将有助于对分子印迹的过程以及分子印迹聚合物分子识别机理的进一步理解,并且对于根据模板分子的性质预测MIP的分子识别能力也将具有一定的指导意义。     

绿原酸印迹均匀微球的制备及其色谱行为研究

以绿原酸为模板,甲基丙烯酸为功能单体,二乙烯基苯为交联剂,采用沉淀聚合法制备了绿原酸印迹均匀微球。探讨了模板及功能单体类型和用量对聚合物颗粒均匀性的影响,考察了流动相组成及柱温对分子印迹柱色谱保留和选择性的影响。绿原酸均匀印迹微球的制备条件为：模板-功能单体-交联剂的用量比为0.375:1.5:7.0,摇瓶转速为15r/min时,微球直径约2.5μm,聚合物收率为35.4%。流动相组成及含水量对印迹聚合物的保留行为影响较大,当用乙腈-水混合物为流动相时,含水量增加,各化合物在印迹色谱柱上的容量因子降低：当流动相含水量高于2.5%,分子印迹聚合物失去选择识别能力;但以0.002mol L_-1磷酸缓冲液(pH3.0)-乙腈混合液为流动相时,分子印迹柱对模板的容量因子、选择性及色谱峰形都有较大改进。当二者体积比为19:1,容量因子高达90.69,其选择性相对于没食子酸和原儿茶酸高达23.10和6.562。温度影响分子印迹聚合物的选择保留能力,当温度从25℃提高到45℃时,印迹聚合物对模板的容量因子从3.52降低到2.41,选择因子降低约30%。     

选择性富集分离虎杖中白藜芦醇苷的分子印迹聚合物的制备及分子识别性能研究

以白藜芦醇苷(POL)为模板分子,分别以丙烯酰胺(AM)、4-乙烯基吡啶(4-VP)、甲基丙烯酸羟乙酯(HEMA)、甲基丙烯酸(MAA)为功能单体,二甲基丙烯酸乙二醇酯(EGDMA)为交联剂,偶氮二异丁腈(AIBN)为引发剂,采用本体聚合法制备白藜芦醇苷分子印迹聚合物。采用静态平衡结合实验研究了印迹聚合物对模板分子及不同底物的识别性能。结果表明,以丙烯酰胺为功能单体的印迹聚合物(MIP1)对模板分子的识别性能最好,其次是以4-VP为功能单体的聚合物(MIP2),以HEMA为功能单体的聚合物(MIP3)以及以MAA为功能单体的聚合物(MIP4)的分子识别性能较差。表明功能单体与模板分子之间相互作用的强弱对MIP的识别能力有较大的影响。静态平衡结合法以及Scatchard分析法表明,MIP1对模板分子呈现较好的结合能力和选择性,该印迹聚合物中形成了2类不同的结合位点,离解常数分别为7.43×10-5、3.70×10-3mol/L。将MIP1用于虎杖提取物中POL的固相萃取分离,效果良好。     

氨基安替比林分子原位烙印柱的制备及其水中结合性质的研究

实验采用原位聚合法以甲基丙烯酸(MAA)为功能单体，乙二醇二甲基丙烯酸酯(EDMA)为交联剂，偶氮二异丁扉(AIBN)为引发剂，正十二醇和甲苯为致孔剂直接在液相色谱柱中制备了氨基安替比林分子烙印柱．讨论了模板分子及其类似物在有机相和水相中的色谱行为及作用机理．实验表明，在水相中烙印柱具有很强的保留性能，氨基安替比林的保留因子可达到94．41．结果认为离子作用和疏水作用是使得氨基安替比林及类似物具有很强的保留性的重要原因，为研究模板聚合物的结合特性，采用前流分析法分别测定了氨基安替比林、氨基比林和安替比林在烙印柱上的吸附等温线．实验表明，分子烙印聚合物对烙印分子表现了较高的选择性，这和通过比较各物质在分子烙印柱和空白柱上保留因子所获得的结果一致．     

赤霉酸分子印迹聚合物及印迹膜的制备与性能研究

以赤霉酸(GA3)为印迹分子,改变功能单体与致孔剂种类合成了四个分子印迹聚合物(MIP1-4)及两个分子印迹膜(MIM1-2).采用紫外光度法分别测定了印迹分子分别与功能单体丙烯酰胺(AM)和甲基丙烯酸(MAA)间的结合常数和化学计量比(n＝2).平衡结合实验研究表明,以AM为单体制备的MIP1对印迹分子GA3具有更高的结合量和良好的印迹效率.膜渗透及膜过滤实验表明,以AM为单体制备的MIM1对GA3分子具有一定的选择性分离性能.     

反相气相色谱研究金属离子中介甲醛印迹聚合物的气相识别

采用配位聚合法制备了Co2+中介的甲醛印迹聚合物,用红外光谱和扫描电镜研究了分子印迹聚合物的表面结构。以甲醛印迹聚合物作为气相色谱固定相,采用反相气相色谱技术研究了印迹材料对模板及其结构相似物的选择保留性能、等温吸附及吸附热力学,并探讨了分子印迹聚合物对室内空气中甲醛的脱除效果。结果表明,在相同色谱条件下,分子印迹柱对模板分子的容量因子均远高于乙醛。较低柱温和较低载气流速有利于印迹材料对气态模板分子的选择保留,当柱温为90℃,载气流速7.0 mL/min,进样体积为3.0μL时,分子印迹柱对模板的容量因子高达61.1,对模板及结构类似物的分离因子达到10.66。模板分子在印迹聚合物柱上的气相吸附等温线呈近似线性,而结构类似物乙醛的吸附等温线符合BET吸附的Ⅲ类模型。分子印迹聚合物对室内空气中的甲醛也具有一定的脱除能力。     

林可霉素分子印迹聚合物的制备及吸附性能研究

以林可霉素(LIN)为模板,利用分子模拟方法模拟丙烯酰胺(AM)、甲基丙烯酸(MAA)、2-乙烯基吡啶(2-VP)和4-乙烯基吡啶(4-VP)4种常见的功能单体与模板分子的结合能,结果表明4-VP结合能最强为-98.25 kJ/mol。用悬浮聚合法制备林可霉素分子印迹聚合物(MIP)并对其性能进行评价。使用气相色谱检测各功能单体制备的印迹聚合物的吸附量,结果4-VP制备的印迹聚合物吸附量最大为102.8μmol/g,分子模拟结果与吸附试验结果一致,表明分子模拟可以为功能单体选择提供依据。采用静态吸附试验和动态吸附试验对印迹聚合物吸附性能表征,并进行了Scatchard模型分析。结果印迹因子为2.54,并且在150 min内较快地达到吸附平衡,表明林可霉素分子印迹聚合物具有较高的选择吸附性,可用于林可霉素的富集。     

左氧氟沙星印迹聚合物微球及其特异吸附研究

以甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,采用沉淀聚合法制备了左氧氟沙星印迹聚合物(MIP)微球,用SEM和IR分别对微球形貌和结构进行表征,用静态吸附法和Scatchard分析考察了聚合物微球对模板及其结构类似物的吸附行为和选择性识别能力.结果表明,MIP对模板分子的吸附平衡速度快,40min即可达到吸附...     

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.