1,4—二氢吡啶及其衍生物电化学反应机理的研究

研究了１１种１，４－二氢吡啶及其衍生物在乙腈溶剂中和铂盘电极上的电化学行为。实验结果表明：１，４－二氢吡啶及其衍生物在铂盘电极上的反应是受扩散和化学反应速率控制的两电子不可逆氧化过程，经连续两步失电子脱氢后形成相应的吡啶。用紫外吸收光谱电化学方法观测了电化学氧化过程。并与化学氧化产物的紫外光谱作了比较，证明１，４－二氢吡啶的电化学氧化产物与化学氧化产物一致。因此，电化学氧化是一种不需加化学试剂可使     

1,4—二氢Hantzsch吡啶衍生物的合成及其^1H NMR和荧光 …

报道了Ｎ－甲基－４－芳基－２,６－二甲基－３,５－二乙基－１,４－二氢吡啶（２ａ－２ｆ）,４芳基－２,６－二苯基－３,５－二乙酯基－１,４－二氢吡啶（３ａ－３ｆ）及其相应的Ｎ－甲基化合物（４ａ－４ｆ）的合成（芳基ｐ－ＲＣ６Ｈ４－;Ｒ＝ＯＣＨ３,ＣＨ３,Ｈ,Ｃｌ,ＣＮ,ＮＯ２）,化合物４－芳基２,６－二甲基－３,５－二乙酯基－１,４－二氢吡啶（１ａ－１ｆ）可发射较强的荧光,化合物３呈现较弱的荥光,它     

应用微波辐射技术一步合成4－芳基－1，4－二氢吡啶衍生物

以芳醛、乙酰乙酸乙酯、醋酸铵为原料在无溶剂条件下应用微波技术合成了4 －芳基－2，6－二甲基－3－5－二乙氧羰基－1，4－二氢吡啶，该反应的2－5min 内完成，产率73％－99％。     

微波固相合成苯并[a]分恶嗪衍生物

首次在固相条件下微波辐射Ｎ，Ｎ－二烷基－４－亚硝基苯胺盐酸盐和２－萘酚生物快速合成苯并「ａ」吩恶嗪衍生物，得到苯并「ａ」吩恶嗪锌离子氯化物３ａ－３ｆ，且收率较高。此外，Ｎ，Ｎ－二甲基－４－亚硝基苯胺盐酸盐和１，３－二羟基－２－萘甲酸乙酯的混合物在微波辐射下合成了一个新的激光染料９－二甲氨基－６－乙氧羰基－５Ｈ－苯并「ａ」的吩恶嗪－５－酮４。     

微波快速合成α—巯基—β—（4—甲氧基）苯基丙烯酸

１引言α－巯基－β－（４－甲氧基）苯基丙烯酸是一种高灵敏度、高选择性的显色剂，可用于痕量镍的测定［１］，也是一种重要的有机合成中间体。本文报道在微波辐射条件下由对甲氧基苯甲醛和绕丹宁快速缩合成对甲氧基苯亚甲基绕丹宁，然后对甲氧基苯亚甲基绕丹宁在氢氧化...     

苯甲酸（1H－1，2，4－三唑－1－基）－3，3－二甲基－2－丁酮酯衍生物的合成

用冠醚作催化剂，通过苯甲酸盐同１－溴代－１－（１Ｈ－１，２，４－三唑－１－基）－３．３－二甲基丁酮－２－反应，合成了一系列苯甲酸（１Ｈ－１，２，４－三唑－１－基）－３，３－二甲基－２－丁酮酯类新化合物，并对合成方法进行了探讨。通过ＩＲ、￣１ＨＮＭＲ及元素分析，确定了化合物的结构。     

有机化学试题选登

有机化学试题选登一、完成下列反应二、合成１．自苯合成２－苯基吲哚２．自硝基苯合成６，６’联喹啉３．自丙二酸二乙酯及必要试剂合成２－甲基－４－异丙基１，３环己二酮４．自丙二酸二乙酯及必要试剂合成β－（３－环己烯基）丙酸５．自乙酰乙酸乙酯合成４－甲基－４...     

1，2，4－三嗪类化合物的研究（ⅩⅫ）──咪唑并－（5，4－e）－1，2，4－三嗪衍生物的合成

１，２，４－三嗪类化合物的研究（ⅩⅫ）──咪唑并－（５，４－ｅ）－１，２，４－三嗪衍生物的合成沙耀武，蔡孟深（北京医科大学药学院，北京，１０００８３）关键词乙二脒腙，原甲酸三乙酯，１，２，４－三嗪，咪唑并－（５，４－ｅ）－１，２，４－三嗪天然碱基拮抗...     

酰氨基硫脲及相关杂环衍生物研究（XXV）──1－［5′－氨基－1′－（4″－氯苯基）－1′，2′，3′－三唑－4′－甲酰基］－4－芳基氨基硫脲的合成和波谱研究

通过５－氨基－１－（４′－氯苯基）－４－甲酰肼基－１，２，３－三唑与芳基异硫氰酸酯的反应，合成了１３种新的１－［５′－氨基－１′－４″－氯苯基）－１′，２′，３′－三唑－４′－甲酰基］－４－芳基氨基硫脲类化合物３ａ－１，经元素分析、ＩＲ、１ＨＮＭＲ以及ＭＳ确证其结构。     

非对映消旋体2—氨基—3—氰基—1—苯基—4—（3,4—亚甲二氧苯 …

用低价钛试剂（ＴｉＣｌ４－Ｚｎ）与３－氧代－１－（３′，４′－亚甲二氧苯基）－３－苯基丙基－１－丙二腈反应合成了非对映消旋体（１Ｓ，４Ｒ；１Ｒ，４Ｓ）和（１Ｓ，４Ｓ：１Ｒ，４Ｒ）２－氨基－３－氰基－１－苯基－４（３－４－亚甲二氧苯基）－２－环戊烯－１－醇，用Ｘ射线衍射分析确定了这两个异构体的相对构型。     

A macrothermodynamic approach to the limit of reversible capillary condensation

The threshold of reversible capillary condensation is a well-defined thermodynamic property, as evidenced by corresponding states treatment of literature and experimental data on the lowest closure point of the hysteresis loop in capillary condensation-evaporation cycles for several adsorbates. The nonhysteretical filling of small mesopores presents the properties of a first-order phase transition, confirming that the limit of condensation reversibility does not coincide with the pore critical point. The enthalpy of reversible capillary condensation can be calculated by a Clausius-Clapeyron approach and is consistently larger than the condensation heat in unconfined conditions. Calorimetric data on the capillary condensation of tert-butyl alcohol in MCM-41 silica confirm a 20% increase of condensation heat in small mesopores. This enthalpic advantage makes easier the overcoming of the adhesion forces by the capillary forces and justifies the disappearing of the hysteresis loop.     

DNA condensations on mica surfaces induced collaboratively by alcohol and hexammine cobalt

We performed systematic studies of λ-DNA condensation on mica surfaces induced by alcohol and hexammine cobalt (III) [Co(NH(3))(6)(3+)] using atomic force microscopy (AFM). The critical condensation concentration for [Co(NH(3))(6)(3+)] was found to be about 10 microM; the DNA molecules extended freely on mica when the concentration was below the critical value. The morphology of condensed DNA became more compact with increasing concentration. At about 500 microM [Co(NH(3))(6)(3+)] concentration, no condensation patterns could be observed due to charge inversion of the compact structures resulting in failure of adhesion to the positively charged surfaces. The critical concentration for alcohol was about 15% (v/v). At this concentration, a few intramolecular loops could be observed in the AFM images. With increasing ethanol concentration the condensation pattern became more complicated ranging from flower-like to pancake-like. When the solution contained both alcohol and hexammine cobalt (III), DNA condensation patterns could be observed even when the concentrations of the two condensation agents were lower than their critical values. We observed this phenomenon by adding mixtures of 10% alcohol and 8 microM hexammine cobalt (III) to DNA solutions. The condensation patterns were more compact than those of the condensation agents separately. Typical toroids were found at an appropriate alcohol and hexammine cobalt (III) concentration. The collaborative condensation phenomenon was analyzed by electrostatic interaction and charge neutralization.     

分级冷凝生物油组分富集与组分稳定性研究

利用GC-MS分别检测分级冷凝装置和常规冷凝装置制备的核桃壳生物油,对比常规冷凝生物油与分级冷凝多品级生物油有机组分的相对峰面积,发现分级冷凝对组分富集有较大影响,其中,乙酸在第四级生物油内相对峰面积从5.38%上升至9.44%;愈创木酚在第二级内从3.46%上升至6.23%;紫丁香醇在第一级内从1.48%上升至4.44%;异丁香酚在第一级内从5.52%上升至17.84%。经过75 d、15℃恒温恒湿储存后分级冷凝生物油水分增加,分别增加了1.58%、1.88%、1.80%、2.43%;脂肪类有机物峰面积减小;酚类有机物峰面积增大。第一、二级生物油内小分子有机物含量较少,老化反应强度较低;第三、四级生物油内小分子有机物含量较多,老化反应强度较高。根据GC-MS检测结果将有机物分类,统计各类有机物在储存前后的含量变化,分析储存过程中各类有机物发生的老化反应种类以及反应强度。     

Promoting condensation kinetics of polymeric carbon nitride for enhanced photocatalytic activities

Polymeric carbon nitride(CN)semiconductor by thermal condensation of N-rich precursors has attracted much attention for its capability ranging from photocatalytic and photoelectrochemical energy conversion to biosensing.However,the influence of condensation process on the final structure of CN was rarely studied,making the condensation kinetic far from be fully optimized.Herein,we report the preparation of CN by a simple condensation kinetics modulation using a faster ramping rate during the polymerization process.The modified condensation recipe was even simpler than the conventional one,but led to an improved photocatalytic H2 evolution up to 3 times without any additional chemicals or other complements.Detailed mechanism studies revealed the increase of crystallinity and surface area due to the rapid condensation played the key roles.This work would offer a more facile and effective way to prepare bulk CN for large-scale industrial applications of bulk CN with higher photocatalytic actives for sustainable energy,environmental and biosensing.     

Solid state reaction of aromatic ketones with heteroaromatics

The solid state reactions of p-nitroacetophenone,acetyl-ferrocene with indole were catalyzed by anhydrous zinc chloride or aluminum chloride,and gave exclusively the 1:2 condensation products.The solid state condensation of aromatic ketones with l-phenyl-3-methyl-5-pyrazolone was also investigated,and the 1:1 and 2:1 condensation products were obtained.The structures of eleven new products were determined by IR,MS,1H NMR and elemental analysis.     

Synthesis of a new urea derivative: a dual-functional organocatalyst for Knoevenagel condensation in water

A phenylalanine–urea compound-catalyzed Knoevenagel condensation in water is reported. Various aldehydes and active methylene compounds undergo condensation at room temperature to give the desired products in high yields. The mechanism of the condensation of aldehydes with Meldrum’s acid catalyzed by the novel urea derivative is also disclosed.     

环丙沙星的合成工艺改进

对环丙沙星(1)的合成工艺进行了改进。在2,4-二氯-5-氟苯乙酮和碳酸二甲酯的缩合反应中,用甲醇钠代替氢化钠;在乙氧亚甲基化反应中,用N,N-二甲基甲酰胺二甲缩醛代替价格昂贵的原甲酸三乙酯;在哌嗪取代反应中,采用硼络合物的方法,提高了取代反应的选择性。1及其中间体的结构经1H NMR确证。缩合反应收率80.6%,亚甲基化和胺化的总收率70.8%,哌嗪取代收率90.8%。     

Kinetics of supersaturated vapor nucleation on molecular condensation nuclei

The kinetics of nucleation is calculated for a supersaturated vapor containing molecular condensation nuclei, that is, foreign molecules able to induce the formation of viable nuclei of a condensed phase by themselves. In contrast to the previous calculation, the possibility of the escape of molecular condensation nuclei from very small clusters containing a few condensed vapor molecules is taken into account. More exact equations are derived for the rate of steady-state nucleation and the concentration of aerosol particles in a quasisteady-state regime of nucleation. The calculation demonstrates that, at a high probability of the escape of a molecular condensation nucleus, the predominating mechanism of cluster formation is the attachment of a molecular condensation nucleus to a cluster formed from vapor molecules rather than their condensation on the nucleus. At the same time, allowances for the possible escape of molecular condensation nuclei from clusters slightly affect the rate of nucleation and the concentration of aerosol particles being formed.     

Role of the spacer of cationic gemini amphiphiles in the condensation of DNA

The condensation of calf thymus DNA into the cholesteric-like psi-phase was observed by circular dichroism in liposome suspensions formulated with specific cationic gemini surfactants. The stereochemistry of the gemini spacer, the presence of specific functional groups, and the covalent link between the headgroups are fundamental issues in the condensation of DNA. Transmission electron microscopy images showed a multilamellar morphology, which corresponds with condensation.     

Synthesis of Some New 2,4-Disubstituted Hydrazinothiazoles and 2,5-Disubstituted Thiazolidinones

A series of hydrazinothiazoles has been synthesized by the condensation of thiosemicarbazones and α-bromoketones. Similarly the hydrazinothiazolidiones were prepared by the condensation of thiosemicarbazone and α-bromoesters. The newly synthesized compounds were characterized by NMR and LCMS studies.