氧化偶联聚合方法合成电活性聚芳醚酮

通过氧化偶联聚合方法成功地合成出电活性聚芳醚酮. 该反应条件温和, 操作简单, 室温下即可进行. 用红外光谱、核磁共振谱、高效凝胶渗透色谱、循环伏安、热失重、X射线衍射等技术对所合成的聚合物进行了表征, 并探讨了聚合物的性能.     

电活性聚芳醚酮类环状分子的合成和性质

将电活性苯胺四聚体链段引入聚芳醚酮类刚性大环分子中, 得到了含电活性苯胺链段的聚芳醚酮类大环状分子低聚物C-1, 并通过循环伏安和紫外滴定法证明了这种新型环状分子具有电活性.     

Synthesis of a novel 14-membered highly constrained cyclic peptidic scaffold

The synthesis and NMR analysis of a novel highly constrained scaffold is described. The 14-membered macrocyclic ring structure was inspired by many medicinally relevant natural products that also contain the bi-aryl ether moiety. The synthesis required only commercially available starting materials and involved a base mediated S_NAr cyclization. A conformational search was performed, which indicated a strong preference for a single conformation, which was consistent with observed ROE signals by NMR.     

Brevisamide: an unprecedented monocyclic ether alkaloid from the dinoflagellate Karenia brevis that provides a potential model for ladder-frame initiation

The dinoflagellate Karenia brevis is known for the production of brevetoxins, a family of polycyclic ether toxins, as well as their antagonist brevenal. Further examination of organic extracts of K. brevis has uncovered yet another unprecedented cyclic ether alkaloid named brevisamide. This report describes the structure elucidation of brevisamide based on detailed MS and NMR spectral analysis, and the importance of this new compound in shedding light on the biogenesis of fused polyethers is discussed.     

Stable dialkyl ether/poly(hydrogen fluoride) complexes: dimethyl ether/poly(hydrogen fluoride), a new,convenient, and effective fluorinating agent

The preparation, (1)H, (13)C, and (19)F NMR structural characterization as well as with DFT-based theoretical calculations of stable dialkyl ether/poly(hydrogen fluoride) complexes are reported. Dimethyl ether/poly(hydrogen fluoride) (DMEPHF), are stable complexes of particular interest and use. The DFT calculations, that are in agreement with NMR data, suggest a cyclic poly(hydrogen fluoride) bridged structure for DMEPHF. The complex, DME-5 HF was found to be a convenient and effective new fluorinating agent with the ease of workup and applied to several fluorination reactions, such as the hydrofluorination and bromofluorination of alkenes, and fluorination of alcohols giving good to excellent yield with high selectivity. Homologous dialkyl ether/poly(hydrogen fluoride) (R(2)O/[HF](n,), R = Et, nPr) systems are also stable and suitable for fluorination reactions.     

Organic crystal engineering with 1,4-piperazine-2,5-diones. 6. Studies of the hydrogen-bond association of cyclo[(2-methylamino-4,7-dimethoxyindan-2-carboxylic acid)(2-amino-4,7-dimethoxyindan-2-carboxylic acid)

[structure: see text] The title 1,4-piperazine-2,5-dione was synthesized in 23% yield over six steps from ethyl 2-amino-4,7-dimethoxyindan-2-carboxylate. Crystallization by slow diffusion of ether into a chloroform solution and by slow evaporation of an ethanol-chloroform-benzene solution produced polymorphic crystalline forms as determined by single-crystal X-ray analysis. The polymorphs exhibited different hydrogen-bonding networks. The association of this piperazinedione in solution was studied using mass spectrometric and nuclear magnetic resonance spectroscopic techniques. The MS and NMR data were interpreted using the solid-state structures as models for solution aggregation. Association constants extracted from the NMR data are in line with those of other cyclic cis amides in chloroform solvent.     

A cytotoxic triketone-phloroglucinol-bullatenone hybrid from Lophomyrtus bullata

Cytotoxic activity against the P388 cell line was seen in a crude extract of the New Zealand shrub Lophomyrtus bullata(Myrtaceae). Bioactivity-guided isolation led to a compound with NMR spectra complicated by the presence of two isomers. These crystallised together and an X-ray structure showed them to be stereoisomeric hybrids of triketone, phloroglucinol and bullatenone units. NMR measurements on the mixed isomers, as well as a cyclic ether produced from them by acid catalysed dehydration, were consistent with these structures. The natural products, named bullataketals A and B, have cytotoxic activity against the P388 cell line (IC(50) 1 microg ml(-1)), and antimicrobial activity against Bacillus subtilis.     

Laurefurenynes A-F, new Cyclic Ether Acetogenins from a Marine Red Alga, Laurencia sp.

We report here on the discovery and structure determination of three new diastereomeric pairs of cyclic ether acetogenins, laurefurenynes A-F, isolated from the aqueous extract of the alga Laurencia sp. collected in the Philippines. Extensive use was made of NMR spectroscopic data and high resolution MS to determine the structures of the pure compounds. The most stable and the lowest energy conformation was determined using molecular modelling, and their cytotoxic activity was tested against different tumour cells, a significant indication that laurefurenyne C and F are moderately cytotoxic, but non-selective whilst the others are inactive.     

γ-Ray-induced copolymerization of carbon monoxide with cyclic ethers

The γ-ray copolymerization of carbon monoxide with cyclic ethers, such as ethylene oxide, phenyl glycidyl ether, 1,3-dioxolane, 2-vinyl-1,3-dioxolane, terahydrofuran, 1,4-dioxane, and acetaldehyde was studied. A yellowish or brownish powdery copolymer was obtained in most of the cases examined. The infrared spectra showed that copolymers containing the ester structural unit were produced in the copolymerization with cyclic ethers which have no vinyl groups, and that a copolymer containing a ketone structure was produced from cyclic ether having vinyl group. It was found that the copolymer with ethylene oxide also had a β-propiolactone ring structure at the chain end or the side chain. The copolymers were confirmed to be partially crystalline from the x-ray diffraction diagrams. Further, a ring-opening polymerizability of the cyclic ether by γ-radiation was discussed. And it was found that as the bond dissociation energy between the carbon–oxygen linkage of the cyclic ether is small, the polymer yield both in the homopolymerization and copolymerization with carbon monoxide is high. A mechanism for the copolymerization is proposed on the basis of the results.     

界面缩聚法合成双酚A芳香环状聚醚砜

聚芳醚（酮、砜）是一类耐高温、耐溶剂的高性能的聚合材料,具有很好的机械和加工性能,广泛应用于工程塑料及复合材料等领域．线性聚芳醚（酮,砜）一般由亲核取代反应或亲电取代反应在极性溶剂中制得,Ｙｏｓｈｉｏ等［１］报道利用相转移催化法制备聚芳醚砜,近年来,...     

Preparation of polyfunctional oligoethers

Copolymerization of epichlorohydrin with allyl glycidyl ether under the action of boron trifluoride tetrahydrofuranate in diethyl ether and dimethoxyethane was studied under the conditions of synthesis of alkyl ether and diols where water was used to produce terminal hydroxy groups. ¹H NMR spectroscopy showed the formation of a copolymer. The integrated intensity ratio for the signals related to allyl and other groups showed that the rate of allyl glycidyl ether introduction into the copolymer is higher than that of epichlorohydrin. Alkyl- and hydroxy-containing oligoethers with enhanced content of functional groups of different nature were obtained by polymer analogous reaction.     

聚硫醚醚酮(砜)芳香环状低聚物的合成与自由基开环聚合

在“拟高稀释”条件下,通过亲核缩聚反应高产率地合成了含硫醚键的芳香醚环状低聚物.应用核磁、GPC和激光质谱(MALDI-TOFMS)等手段对环状低聚物的结构进行了确认,并研究了环状低聚物的组分分布.聚硫醚醚酮环状低聚物在硫醚自由基的引发下进行快速熔融聚合,得到热稳定性很好的高分子量线性聚合物.     

Marinopyrrole A衍生物合成方法的优化

以双醛化合物1为原料, 通过取代基保护、 分步加成、 氧化、 脱Ts(对甲苯磺酰基)、 氯代和脱甲基等反应, 以9步反应13%的总收率合成了苯环6位含氟取代的Marinopyrrole A衍生物12, 所合成化合物的结构经IR, ¹H NMR, ¹³C NMR和HRMS分析确证. 分步加成和氧化的应用有效避免了原合成方法中环醚中间体3的生成, 提高了反应总收率, 为系列Marinopyrrole A 衍生物的合成提供了一种新方法.     

Syntheses and properties of sila-functional oligosiloxanes: Synthesis, structure, and spectra of linear and cyclic isocyanato(methyl)oligosiloxanes

Synthesis, structure, and spectra of novel linear and cyclic isocyanato(methyl)oligosiloxanes with the silicon number up to eight were investigated. The linear and cyclic oligosiloxanes were synthesized selectively in good or appreciable yields by vapor phase and liquid phase hydrolysis, respectively. They were isolated as liquids by distillation under reduced pressure except for cyclic tetrasiloxane and pentasiloxane which were provided as solids. The cyclic trisiloxane was obtained as amixture of isomers as confirmed by nuclear magnetic resonance (NMR) spectra. The X-ray analysis of cyclic tetra- and pentasiloxane obtainedrevealed that they have cis-trans-cis andpropeller-like structure, respectively. The infrared (IR) spectra of cyclic siloxanes showed a sharp peak due to ν_Si?O?Si and a remarkable shift fromthe tri- to the tetrasiloxane while peak broadening and almost no shift were observed for the higher homologues. On the other hand, the sharp peak for linear disiloxanes became broad and split into two peaks for the higher homologues, while the peak at low wavenumber shifted even lower as the siloxane linkages increased, yet no corresponding shift is observed for thepeak at higher wavenumber. In the ²⁹Si NMR spectra of linearoligosiloxanes, the signals appeared separately at low and high fields in narrow regions, which are ascribed to the terminal silicon atom and the silicon associatedwith the silylmethyl groups, respectively. These regions hardly changed, regardless of the length of siloxane linkage. Similar trends were observed in the ¹H and ¹³C NMR spectra.     

Interpretation du Spectre RMN de l'Octaacetate de Cellobiose a 250 MHz. Application au Triacetate de Cellulose

Using a 250 MHz NMR spectrometer and double resonance experiments the full identification of the 14 cyclic protons of α octaacetate cellobiose has been performed. The results obtained here are of particular interest as affording an answer to the problem of the existence of particular signals in the NMR spectra of cellulose triacetate. These signals are both due to the anomeric extremity of the polymer.     

Synthesis, characterization and electrochemical investigation of a novel vic-dioxime ligand and its some transition metal complexes

4-(Chloroacetyl)diphenyl ether was synthesized from chloroacetyl chloride and diphenyl ether in the presence of AlCl₃ as catalyst in a Friedel-Crafts reaction. Then, its keto oxime and dioxime derivatives were prepared. 4-phenoxy-(N-4-chlorophenylamino)phenylglyoxime (H₂L) was synthesized from 4-(phenoxy)chlorophenylglyoxime and 4-chloroaniline. Ni(II), Co(II) and Cu(II) complexes of H₂L were obtained. The mononuclear Ni(II), Co(II) and Cu(II) complexes of H₂L have a metal–ligand ratio of 1:2 and the ligand coordinates through the two N atoms, as do most of the vic-dioximes. The structure of the ligand was identified by FT-IR, ¹H NMR, ¹³C NMR, ¹³C NMR (APT) spectroscopy and elemental analysis data. The structures of the complexes were characterized on the basis of FT-IR, ICP-AES, UV-Vis, elemental analysis, magnetic susceptibility measurements, and cyclic voltammetry. The electrochemical measurements were obtained by using cyclic voltammetry in DMF solution at room temperature. The electrochemical behaviors of H₂L and its complexes showed that the redox process of H₂L has one irreversible oxidation wave, whereas the redox processes of the complexes have both oxidation and reduction waves with metal centered.     

Silicon-Modified Carbohydrate Surfactants II: Siloxanyl Moieties Containing Branched Structures

Branched siloxanyl-modified carbohydrate surfactants have been synthesized by coupling mono-, di- and poly-functional siloxanes to carbohydrate units either via a branched spacer or by attaching a separate modifying element to a straight-chained structure. Hydrophilic as well as extremely hydrophobic elements have been incorporated successfully. Siloxanyl-modified carbohydrates bearing a secondary amino function were alkylated in regioselective reactions by different epoxides ranging from glycidol- to siloxanyl-modified allyl glycidyl ether derivatives. Alternatively, carbohydrate-modified piperazinyl structures yielded cyclic subunits after alkylation. Structures bearing two identical hydrophilic groups are accessible by alkylation of carbohydrate-modified bisamides. The derivatives synthesized were characterized by means of GC, NMR and elemental analysis.     

Localization and moving of a proton inside hydrogen-bonded complexes in aprotic solvents

The results of the study of a number of molecular and ionic H-bonded complexes in freon solutions by ¹H NMR at 100–150 K are reported. It is shown that under these conditions the signals of OH(NH) protons belonging to various complexes, self-associates and free molecules are observed separately. The spin-spin coupling of the signals is frequently discernible. The fine structure makes it possible to distinguish between complexes with fast proton migration between two wells on the potential surface and those with the proton localized in one well (in particular, the central one). Several complexes with slow (in the NMR scale) proton migration have also been found.The results of the study of the non-catalytic proton exchange kinetics between various molecules containing OH and NH groups in dilute solutions in aprotic solvents are considered. The exchange between the RCOOH and ROH molecules goes on via the intermediate formation of a cyclic ionic pair with two equivalent H-bonds even in non-polar solvents such as cyclohexane. For exchange between two RCOOH or ROH molecules a synchronous transfer of two protons in a cyclic molecular complex is likely.     

Pathways of Methane Transformation over Copper‐Exchanged Mordenite as Revealed by In Situ NMR and IR Spectroscopy

The reaction of methane with copper‐exchanged mordenite with two different Si/Al ratios was studied by means of in situ NMR and infrared spectroscopies. The detection of NMR signals was shown to be possible with high sensitivity and resolution, despite the presence of a considerable number of paramagnetic Cu^II species. Several types of surface‐bonded compounds were found after reaction, namely molecular methanol, methoxy species, dimethyl ether, mono‐ and bidentate formates, Cu^I monocarbonyl as well as carbon monoxide and dioxide, which were present in the gas phase. The relative fractions of these species are strongly influenced by the reaction temperature and the structure of the copper sites and is governed by the Si/Al ratio. While methoxy species bonded to Brønsted acid sites, dimethyl ether and bidentate formate species are the main products over copper‐exchange mordenite with a Si/Al ratio of 6; molecular methanol and monodentate formate species were observed mainly over the material with a Si/Al ratio of 46. These observations are important for understanding the methane partial oxidation mechanism and for the rational design of the active materials for this reaction.     

Pathways of Methane Transformation over Copper-Exchanged Mordenite as Revealed by In Situ NMR and IR Spectroscopy

The reaction of methane with copper-exchanged mordenite with two different Si/Al ratios was studied by means of in situ NMR and infrared spectroscopies. The detection of NMR signals was shown to be possible with high sensitivity and resolution, despite the presence of a considerable number of paramagnetic Cu^II species. Several types of surface-bonded compounds were found after reaction, namely molecular methanol, methoxy species, dimethyl ether, mono- and bidentate formates, Cu^I monocarbonyl as well as carbon monoxide and dioxide, which were present in the gas phase. The relative fractions of these species are strongly influenced by the reaction temperature and the structure of the copper sites and is governed by the Si/Al ratio. While methoxy species bonded to Brønsted acid sites, dimethyl ether and bidentate formate species are the main products over copper-exchange mordenite with a Si/Al ratio of 6; molecular methanol and monodentate formate species were observed mainly over the material with a Si/Al ratio of 46. These observations are important for understanding the methane partial oxidation mechanism and for the rational design of the active materials for this reaction.