一种具有高度选择性的技术——分子烙印

分子烙印技术作为一个新概念被提出来 ,虽然国外已有一部分人在这方面作出了一些研究 ,但国内这方面的报道却很少 ,本文从自组装方式和预聚合方式两种合成分子烙印聚合物的模型 ;烙印分子、功能性聚合物单体及聚合条件的选择 ;分子烙印聚合物的特点、应用及展望等作了评述     

分子烙印技术在分析化学中的应用

分子烙印技术是一种制备具有特定选择性和亲合性的分子识别材料的技术。它在烙印分子存在的情况下,功能性单体与交联剂共聚制得高交联的聚合物网络,移去烙印分子后就得到了对烙印分子记忆效应的分子烙印聚合物。它在分析化学,催化和有机合成等领域都具有应用价值。该文主要介绍了烙印聚合物在分析化学中的应用研究,着重于它在色谱技术中的应用,尤其是在毛细管电色谱中的应用。最后对该技术的发展前景进行了讨论。     

一种具有高速选择性的技术—分了烙印

分子烙印技术作为一个新概念被提出来,虽然国外已有一部分人在这方面作出了一些研究,但国内这方面的报道却很少,本文从自组装方法和预聚合方法两种合成分子烙印聚合物的模型,烙印分子、功能性聚合物单体及聚合条件的选择,分子烙印聚合物的特点,应用展望等作了评述。     

分子烙印技术简介

分子烙印技术的基本思想是源于人们对抗体—抗原或酶的专一性的认识 ,即一种抗体只能针对一种抗原 ,一种酶只能选择性的催化一种或固定的几种底物 ,而分子烙印技术则通过人工的方法合成与目标分子耦合的大分子化合物 :以目标分子为模板 ,将具有结构互补的功能化聚合物单体分子通过共价键或非共价键的方式与模板分子结合 ,加入单体进行聚合反应 ,反应完成后将模板分子提取出来后形成具有空穴的能识别模板分子的高分子。用这种基于仿生方法合成的大分子聚合物即为分子烙印聚合物 ,它与模板分子的位置 ,形状 ,官能团互补[4 ] ,对模板分子具有高…     

分子烙印聚合物作为高效毛细管电泳添加剂的研究

分子洛印聚合物（molecular imprinted polymer)是一种高选择的有分子记忆效应的主体分子,通常在非极性环境中制备和应用。该文在极性溶剂中利用离子化作用和疏水作用制备了非共价的分子烙印聚合物,并将其作为高效毛细管电泳流动相添加剂;在含水缓冲溶液条件下,研究了单体种类、分子烙印聚合物颗粒度和含量、缓冲溶液pH值以及分离电压对分子烙印聚合物识别模板分子的影响。结果证明了在质子溶剂中制备和应用非共价分子烙印聚合物是可行的。     

分子烙印聚合物的结构表征及手性拆分中的热力学研究

考察了一系列分子烙印聚合物的热稳定性和孔结构,探讨了孔结构与手性选择性的关系。计算了手性分离过程中的某些热力学参数的变化,发现分子烙印聚合物上的手性分离是一个焓控制的过程,热力学参数的变化同烙印分子的结构有关。     

分子烙印技术的应用与最新进展

分子烙印技术是合成对模板分子具有特定识别能力的聚合物的技术。在第一届分子烙印技术国际会议报告文集的基础上对117篇文献进行了综述。总结了最近分子烙印技术在对映体或立体异构体分离、固相萃取、化学传感器和模拟生物传感器及催化生物反应工程方面取得的成绩和存在的问题。扼要介绍了在分子烙印技术发展过程中出现的新方法、新用途，指明了分子烙印技术的发展趋势。     

分子烙印聚合物为固定相分离和识别磺胺类药物

以磺胺甲噁唑为模板分子,采用原位聚合法制备了具有特定识别性能的棒状分子烙印聚合物。作为高效液相色谱的固定相实现了磺胺甲噁唑与其结构类似物的分离。磺胺甲噁唑烙印聚合物和目标分子之间的相互作用除了特异性的氢键作用外,也存在着疏水作用。同时考察含水量、流速对分离的影响,论证了分子烙印聚合物选择性专一的作用原理。结果表明,这种棒状聚合物对模板分子及其类似物有很好的分离能力。     

分子烙印聚合物固定相分离咖啡因和茶碱的研究

分子烙印是一种新兴的分子识别技术,利用该技术可制备对烙印分子具有“预定”识别能力的高分子聚合物,即分子烙印聚合物（MIP）,从而可以对性质和组成相近的组如对映体等进行分离^[1,2],咖啡因与茶碱的分子烙印聚合物的制备以及二者分析已有报道^[3-9],但存在两种完全相反的结论。一种观点认为,即使以咖啡因为烙印分子,所制备的聚合物对咖啡因分子的选择性吸附能力也小于茶碱^[3-6]。而另一种观点则认为,在一定条件下,如以咖啡因分子为烙印分子的烙印聚合物对咖啡因分子具有更强的吸附能力^[7-9]。本文分别采用茶碱和咖啡因作为烙印分子,以甲基丙烯酸等为功能单体,在不同条件下制备了多种非共价型分子烙印聚合物,并系统地考察了其作 为HPLC固定相对咖啡因和茶碱的分离能力,同时也对烙印分子应具备的条件加以探讨。     

磺胺二甲嘧啶分子印迹聚合物的合成及其识别性能

磺胺二甲嘧啶分子印迹聚合物的合成及其识别性能;磺胺二甲嘧啶;分子印迹聚合物;硅胶;分子识别     

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.