The synthesis and structure of 1,3,4-trisubstituted 2,5-dioxopyrrolidines and their behaviour in liquid crystalline systems

To find novel compounds for liquid crystalline mixtures with improved properties, a series of optically active 1,3,4-trisubstituted 2,5-dioxopyrrolidines has been prepared. Their structure was confirmed by IR spectroscopy. The twisting ability of the compounds prepared was studied.     

金纳米粒子修饰聚合物固相微萃取整体柱的制备及其性能研究

通过在毛细管聚合物整体柱表面修饰金纳米粒子,制备了一种可选择性捕获含巯基化合物的固相微萃取整体柱.首先制备聚(甲基丙烯酸缩水甘油酯-乙二醇二甲基丙烯酸酯)整体柱,在其表面化学修饰半胱胺;通过半胱胺上的巯基基团将金纳米粒子固定在整体柱的孔表面.以巯基类化合物为探针,评价了固相微萃取整体柱的萃取性能.结果表明,由于Au对巯...     

5-(5-Aryl-1,3,4-oxadiazole-2-carbonyl)furan-3-carboxylate and new cyclic C-glycoside analogues from carbohydrate precursors with MAO-B, antimicrobial and antifungal activities

Cyclization of acyclic C-glycoside derivatives 1a,b to 2a,b as the major isomers, and 4a,b as the minor isomers were carried out. The isopropylidene derivatives 3a,b were prepared, as well as the hydrazide derivative 6, which was condensed with a variety of aldehydes to give hydrazones 7a-e which were also prepared from the compounds 12a-e. Acetylation of 7a,d gave the corresponding acetyl derivatives 8a,d, respectively. In addition, the dicarbonyl compound 9 was prepared in the hydrate form, which reacted with a number of aroylhydrazines to give the corresponding bisaroylhydrazones 10a-d, which were cyclized into 1,3,4-oxadiazoles 11a-d. Furthermore, two of the prepared compounds were examined to show the ability to activate MAO-B. In addition a number of prepared compounds showed antibacterial and antiviral activities.     

Synthesis and antimicrobial activity of quinoline-based 2-pyrazolines

A series of 2-pyrazolines was prepared in a reaction of quinolinylchalcones with phenyl hydrazine under both conventional and microwave-induced heating. Structures of the synthesized compounds were characterized by spectroscopic data and CHN analyses. All prepared compounds were tested for antimicrobial activity against bacterial strains, viz. Staphylococcus aureus, Salmonella typhii, Escherichia coli, and Shigella dysentery. Almost all synthesized compounds have shown antimicrobial activity; however, compounds with a chloro group as a substituent have been found to be more effective.     

Synthesis and potent cytotoxic activity of 8- and 9-anilinophenanthridine-7,10-diones

A series of 8-anilino and 9-anilinophenanthridine-7,10-diones was prepared and screened against various cancer cell lines to measure anti-proliferative activity. The compounds tested display potent cytotoxic activity in the micromolar and sub-micromolar range. These compounds are promising new leads for developing anticancer compounds.     

Synthesis and conformational studies of dipeptides constrained by disubstituted 3-(aminoethoxy)propionic acid linkers

A series of cyclic compounds with dimethyl-substituted 3-(aminoethoxy)propionic acid linkers have been prepared as potential beta-turn mimics. The desired linkers were prepared from disubstituted pyrones, which were coupled with dipeptides and then subjected to macrocyclization using diethylcyanophosphonate to furnish cyclic compounds 1-5. Conformational analysis was carried out using NMR and X-ray crystallography. All of the five cyclic compounds were found to exist in type I or type II beta-turn conformations.     

Synthesis and Antimicrobial Activity of New 2,5‐Disubstituted 1,3,4‐Oxadiazoles and 1,2,4‐Triazoles and Their Sugar Derivatives

A series of new 2,5‐disubstituted‐1,3,4‐oxadiazole and 1,2,4‐triazole derivatives were synthesized by heterocyclization of acid hydrazide 1 and thiosemicarbazide derivative 2 . Furthermore, the acyclic C‐nucleoside analogs were prepared by cyclization of their corresponding sugar hydrazones by reaction with acetic anhydride. The antimicrobial activity of the prepared compounds was evaluated and some of the synthesized compounds revealed good activities against fungi.     

Preparation and characterization of a new layered double hydroxide, Co-Zr-Si

The layered double hydroxides (LDHs) are nano-ordered layered compounds and well known for their ability to intercalate anionic compounds. Most LDH is prepared conventionally only with divalent and trivalent cations. In this study, Co-Zr-Si LDH, consisting of divalent, tetravalent, and tetravalent cations, was prepared and reacted with monocarboxylic acids at room temperature. The Co-Zr-Si LDH and intercalated compounds have been characterized by energy-dispersive X-ray spectrometry, X-ray powder diffraction, IR spectra, thermal analysis, and scanning electron microscopy (SEM). The insertion of cyanate and carbonate anions into LDH was confirmed by IR spectra. XRD patterns of the prepared Co-Zr-Si LDH showed that the interlayer spacing of the LDH is 0.78 nm. The spacing is similar to that of usual LDH in which chloride, carbonate, or bromide anion is the guest. SEM images showed that Co-Zr-Si LDH can exist as plate-like or fibrous structures.     

Tetraanthraquinonoporphyrazines: II. Synthesis and Properties of Metal Complexes of Substituted Tetraanthraquinonoporphyrazines

Metal complexes of substituted tetraanthraquinonoporphyrazines were prepared by template synthesis and were reduced to the corresponding leuco compounds. The electronic absorption spectra of the compounds prepared were studied.     

Preparation and properties of electron donor acceptor complexes of the compounds having capto-dative substituents

In order to examine the “capto-dative” substitution-effect on the electrical conductivity, five compounds which have capto-dative substituents were prepared. Electron withdrawing (capto) group was nitro- or cyano-substituted phenyl and electron donating (dative) one was 5-methyl-5,10-dihydrophenazinyl moiety. The character of intramolecular electron donor acceptor complex of the five compounds were demonstrated by their uv spectra. Electron donor acceptor complexes of them with tetracyanoquinodimethane were prepared and their electrical resistivities were measured.     

硝基苯并咪唑衍生物的合成、表征及抑菌活性的测定

以苯并咪唑为原料,经硝化、二茂铁磺酰化等步骤,合成了8种未见文献报道的硝基苯并咪唑衍生物,其结构经MS,¹H NMR和元素分析确证.由于硝基苯并咪唑的互变异构,二茂铁磺酰化后,产生两个异构体,用X射线衍射仪测定了化合物2a的晶体结构.初步的抑菌实验结果表明,该系列化合物具有良好的抑菌作用,其抑菌活性均优于对照药剂50%多菌灵可湿性粉剂.     

Transformations of some 6- and 7-substituted 1,2,3-benzothiadiazoles

The preparation of some 6- and/or 7-substituted derivatives of 1,2,3-benzothiadiazole is described. The reactivity of some compounds was investigated in view of the possibility that 1,2,3-benzothiadiazoles may behave as masked diazo compounds. 7-Diazo or diazonium compounds were prepared but no interaction with the thiadiazole part could be observed.     

Synthesis and characterization of MCM-48 tubular membranes

MCM-48 membranes have been prepared on alumina supports of different pore sizes. A battery of characterization techniques has been used to study the physical properties and the quality of the membranes prepared. The highest quality membranes were prepared on supports with pore size of up to 60 nm. The MCM-48 membranes were tested in the separation of gas phase mixtures and a cyclohexane/O₂ selectivity higher than 270 was obtained. The selective separation of organic compounds from inert components is a result of the cooperative effects of capillary condensation in MCM-48 pores and of the specific interactions of the permeating compounds and the membrane material.     

Liquid crystalline benzothiophenes. Part 3: 2,4- and 2,7-disubstituted benzothiophenes

Five series of compounds based on 2,4- and 2,7-disubstituted benzothiophenes have been prepared and studied with respect to their mesomorphic properties. The molecular structure was modified by prolonging the molecular arms (varying the alkyl chain length) and orientation of the ester linkages. It was established that the transition temperatures and the type of the formed phases strictly depend on the ester orientation and only limited number of prepared compounds exhibited mesomorphic behaviour. Based on X-ray patterns, columnar phases were identified and found that they have centred crystallographic unit cell differing in the lattice parameters for homologous compounds. Although the bend angle of the studied materials is around 90° only, they exhibited formation of phases typical of the bent-shaped liquid crystals.     

Studies on the synthesis of heterocyclic compounds. V. Preparation of 1,3,2-benzoxathiaphosphole,arsole and stibole derivatives by exchange methods

A new convenient method for synthesis of heterocyclic compounds of five-membered rings containing an O-M-S (M = P, As, Sb) linkage is described. The compounds IIIa-c, IVa-b, Va-b, Viand VII were prepared starting from 2,2-dimethyl-1,3,2-benzoxathiastannole (II) and derivatives of phosphorus, arsenic and antimony. The structures of newly prepared compounds was determined by elemental analysis, spectroscopic methods (ir, nmr and ms) and comparison with authentic samples obtained via a different manner.     

氟烷基三甲基硅化合物的合成和反应研究

羰基化合物的氟烷基化反应是把含氟基团引入有机分子中去的一个重要手段。文献报道的主要是通过氟烷基金属试剂来进行此反应。但氟烷基金属试剂不太稳定,容易分解。这就给它们的应用带来了许多不便。我们发现,氟烷基三甲基硅化合物(1)作为氟烷基阴离子前体,在比较温和的条件下,便可使醛发生氟烷基化反应。首先,参照文献方法,通过氟烷基格氏试剂与三甲基氯硅烷反应,方便地制得了两个新的氟烷基三甲基硅化合物 R_F-SiMe_3(1)。     

Tri- and pentacalix[4]pyrroles: synthesis, characterization and their use in the extraction of halide salts

Calixpyrrole-based oligomeric compounds were synthesized by "click chemistry" from the corresponding alkyne- and azide-functionalized calix[4]pyrroles. Calix[4]pyrrole 3, possessing an alkyne functional group, was prepared through a mixed condensation of pyrrole with acetone and but-3-ynyl 4-oxopentanoate. Another alkyne-group-containing calix[4]pyrrole 5 was obtained by treatment of 4'-hydroxyphenyl-functionalized calixpyrrole 4 with propargyl bromide. Tetrakis(azidopentyl)-functionalized calix[4]pyrrole 7 was synthesized by reacting NaN(3) with tetrabromopentyltetraethylcalix[4]pyrrole 6, which was prepared through a condensation reaction of pyrrole and 7-bromohept-2-one. Oligomeric calixpyrrole compounds were found to be capable of extracting tetrabutylammonium chloride and fluoride salts from aqueous media. Extraction abilities of the oligomeric compounds were monitored by NMR and UV/Vis spectroscopy and thermogravimetric analysis.     

New and General Nitrogen Heterocycle Synthesis: Use of Heteropoly Acids as a Heterogeneous Recyclable Catalyst

An efficient synthetic method of six- and five-member nitrogen heterocyclic compounds was developed. Nitrogen heterocyclic compounds were prepared by condensation of the β-dicarbonyl compounds with the corresponding β- or γ-amino alcohols, subsequent cyclization, and spontaneous aromatization in the presence of a catalytic amount of Keggin-type heteropoly acids under very mild conditions.     

Synthesis of potential antifilarial agents 2 . methyl 2-substituted purine 8-carbamates and related compounds

A series of methyl 2-substituted purine 8-carbamates was prepared and evaluated for antifilarial activity. These purines were synthesized as aza congeners of benzimidazole carbamates which have shown significant anthelmintic activity to determine the effect that this modification might have on anthelmintic activity. The compounds were tested against the filarial infection, B. pahangi, in jirds. None of the compounds prepared in this study demonstrated antifilarial activity.     

Schiff碱式双功能离子液体的制备与表征

分步合成法了Schiff碱式双反应中心的功能化离子液体: 首先通过1-丙胺基-3-甲基咪唑氯与FeCl₃合成含有-NH₂的Fe基离子液体; 然后通过1,3-二氨基-2-丙醇与3,5-二叔丁基水杨醛合成Schiff碱配体H₂L及其Co配合物CoL, 再通过4-氯丁酰氯的酰氯基与配合物CoL的-OH反应生成含有-CH₂Cl的配合物CH₂Cl-CoL; 最后通过Fe基离子液体的-NH₂与配合物CH₂Cl-CoL的-CH₂Cl之间的键合反应合成Schiff碱式双功能离子液体. 通过有机元素分析、 红外光谱、 紫外-可见光谱、 核磁共振波谱、 电喷雾电离质谱、 电感耦合等离子体-质谱和拉曼光谱对各化合物进行了结构表征, 确定Schiff碱式双功能离子液体的阳离子为Schiff碱Co络合阳离子, 阴离子为Fe的络合阴离子.