Multicomponent synthesis of spiroisoxazolines

A three-component one-pot procedure (3-MCR) was developed to assemble the spiroisoxazoline nucleus from commercially available materials. This new methodology affords the title compounds in high yields and without the use of chromatography.     

多元多金属含氧簇合物

多金属含氧簇合物是一大类具有独特结构和特殊性能的化合物，对于基础理论研究和实际应用均有重要意义，其中多元多金属含氧簇合物的重要性日益渐增，本文拟对多元多金属含氧簇合物的结构，性能和制备作扼要的评述。     

Photoinduced Multicomponent Reactions

The combination of multicomponent approaches with light‐driven processes opens up new scenarios in the area of synthetic organic chemistry, where the need for sustainable, atom‐ and energy‐efficient reactions is increasingly urgent. Photoinduced multicomponent reactions are still in their infancy, but significant developments in this area are expected in the near future.     

不对称多组分反应

由于多组分反应自身所具有的优势及其在新药发现中的应用,多组分反应特别是不对称多组分反应成为一个非常有吸引力的研究领域。本文从非对映选择性和对映选择性控制两个方面对不对称多组分反应的最新研究进展进行了综述。重点介绍了反应中所使用的催化剂体系及有关反应机理。最后提出了不对称多组分反应研究中存在的一些问题,并对其今后的发展方向进行了展望。     

Multicomponent Metal-Organic Frameworks

Metal-organic frameworks (MOFs) are constructed from metal ions or clusters and organic linkers. Typical MOFs are rather simple, comprising just one type of joint and linker. An additional degree of structural complexity can be introduced by using multiple different components that are assembled into the same framework In the early days of MOF chemistry, conventional wisdom held that attempting to prepare frameworks starting from such a broad set of components would lead to multiple different phases. However, this review highlights how this view was mistaken and frameworks comprising multiple different components can be deliberately designed and synthesized. When coupled to structural order and periodicity, the presence of multiple components leads to exceptional functional properties that can be understood at the atomic level.     

Multicomponent polymer brushes

This article describes a general synthetic route to laterally distinctive multicomponent polymer brushes on gold. The procedure involves repeated surface patterning using microcontact printing (muCP) of initiator-terminated thiols without backfilling with inert thiols and surface-initiated atomic transfer radical polymerization steps. In between brush growth, the remaining initiator moieties are deactivated to avoid reinitiation on existing brushes. Optical and fluorescence microscopy, atomic force microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy have been used to characterize every step of this procedure. We found that brushes can be grown from initiator-modified surfaces that contain bare gold areas and that these areas remain available for further patterning using muCP. To demonstrate the flexibility of this approach, surfaces containing four different polymer brushes in patterns ranging from 2 x 4 microm lines to 20 x 20 microm squares were fabricated. The range of chemical functionalities incorporated includes cationic and anionic polyelectrolytes, as well as thermally responsive polymers.     

Physicochemical characterisation and cyclodextrin complexation of erlotinib

Erlotinib (ERL), the anticancer drug of poor bioavailability, was quantified in terms of bio-relevant physicochemical parameters, such as acid–base properties, lipophilicity and solubility, and a comprehensive study on its inclusion complexation was carried out. The protonation constant of ERL (log K = 5.32) indicates that it exists mainly in deprotonated form at the pH of blood plasma. The high lipophilicity (log p = 2.75) explains its good permeability, while the very low solubility (S₀ = 12.46 μM) causes its low bioavailability and renders injection formulation a difficult job. This problem could be alleviated by enhancing ERL solubility through cyclodextrin (CD) inclusion complexation. Therefore, ERL–CD interactions were studied by a number of analytical techniques. The apparent stability constants of ERL with seven different CDs were determined using affinity capillary electrophoresis. Results indicated that the seven-membered β-CD and its derivatives were the most suitable hosts. Using UV Job plot titration 1:1 stoichiometry was determined, confirmed by electrospray ionisation-mass spectrometry experiments. The geometry of the inclusion complex was investigated by 2D ROESY NMR techniques, revealing that the ethynylphenyl ring enters the β-CD cavity. Phase-solubility analysis shows greatly enhanced solution concentration by CD complexation. The determined equilibrium and structural information offer molecular basis to elaborate improved drug formulation with enhanced bioavailability.     

多元多金属含氧簇合物在催化化学中的应用*

多金属含氧簇合物在催化化学中的重要性与日俱增,在原子经济反应和环境友好催化方面有着诱人的实用前景。这类物种的催化活性、理化性质、分子结构和固态体相结构以及制备方法均能在分子水平上给出详细信息,因而被视为混合金属氧化物催化剂的分子设计材料。本文拟对能够直观反映出这种信息的多元多金属含氧簇合物催化的研究作一评述。     

Multicomponent synthesis of fused benzimidazolopiperazines

We present a novel protocol for the efficient synthesis of fused benzimidazolo piperazines starting from a four-component Ugi-Smiles reaction and a subsequent three-step cascade involving an acid-catalyzed cyclization, an intramolecular reductive cyclization, and an oxidation.     

Multicomponent synthesis of 2-imidazolines

[reaction: see text] A multicomponent reaction (MCR) between amines, aldehydes, and isocyanides bearing an acidic alpha-proton gives easy access to a diverse range of highly substituted 2-imidazolines. The limitations of the methodology seem to be determined by the reactivity of the isocyanide and by the steric bulk on the in situ generated imine rather than by the presence of additional functional groups on the imine. Less reactive isocyanides, for example p-nitrobenzyl isocyanide 25a, react successfully with amines and aldehydes, using a catalytic amount of silver(I) acetate. Some of the resulting p-nitrophenyl-substituted 2-imidazolines undergo air oxidation to the corresponding imidazoles. Differences in reactivity of the employed isocyanides are explained with use of DFT calculations. Difficult reactions with ketones instead of aldehydes as the oxo-compound in this MCR are promoted by silver(I) acetate as well.     

Multicomponent synthesis of chiral sulfinimines

Two oxathiozolidine-S-oxide templates have been developed and used in a four-component coupling protocol for the synthesis of a wide range of chiral sulfinimines in high enantiomeric excesses. The templates can be synthesized from cheap commodity chemicals in three steps in high yields. Furthermore the template is easily recovered in high yields for recycling.     

Multicomponent Synthesis of Luminescent Iminoboronates

A family of iminoboronates was prepared through a one-pot multicomponent reaction, starting from boronic acid, anthranilic acid, and different salicylaldehydes. Their synthesis was straightforward and the complexes were obtained in good to excellent yields. Their photophysical properties were assessed in a diluted solution, and the complexes proved to be faintly luminescent. These chelates demonstrated remarkable Aggregation-Induced Emission Enhancement, which was rationalized using crystal structures.     

多组分参与的氟烷基化反应研究进展

多组分参与的氟烷基化反应是当前有机氟化学研究的一个热点.在过去的几年里,由于新试剂新方法的不断涌现,多组分参与的氟烷基化反应取得了长足的进展,不仅可以经济有效地一步将氟烷基基团与其他官能团同步引入,而且可以将起始原料转化为多种含有生物活性或药物活性的化合物.按照三组分二氟烷基化反应、三组分三氟甲基化反应、三组分全氟烷基化反应、三组分单氟烷基化反应、三组分氟化反应以及四组分氟烷基化反应和总结7个部分,总结了多组分参与的氟烷基化反应在过去近十年时间里的发展进程,同时对该类反应进行了总结和展望.     

Multicomponent two-phase buffer systems

Two-phase buffer systems containing two or more acid—base pairs and having a considerable buffer capacity over a wide pH range are described. When acid—base pairs of the same type are combined, the rule of additivity of buffer capacity is valid, but when the two-phase buffers contain an organic acid and an organic base, the rule of additivity does not apply if ion-pair extraction occurs to a significant extent. Equations for calculation of buffer capacity curves in the latter case are reported. The differentiating effect of the organic solvent allows multicomponent two-phase buffers to be prepared from acids whose strength in water is practically equal.     

Multicomponent Reactions with Isocyanides

Multicomponent reactions (MCRs) are fundamentally different from two-component reactions in several aspects. Among the MCRs, those with isocyanides have developed into popular organic-chemical reactions in the pharmaceutical industry for the preparation of compound libraries of low-molecular druglike compounds. With a small set of starting materials, very large libraries can be built up within a short time, which can then be used for research on medicinal substances. Due to the intensive research of the last few years, many new backbone types have become accessible. MCRs are also increasingly being employed in the total synthesis of natural products. MCRs and especially MCRs with isocyanides offer many opportunities to attain new reactions and basic structures. However, this requires that the chemist learns the "language" of MCRs, something that this review wishes to stimulate.     

多组分聚合体系的探索

多组分反应是利用三种或者三种以上反应物一锅法得到终产物的反应。在此过程中,无需对中间产物进行分离提纯,而且几乎所有反应物的原子都出现在生成物当中。因此多组分反应经常被用来合成具有复杂结构的化合物。我们在多组分反应中引入可聚合元素,将功能化单体合成和可控聚合结合在一起,一步合成具有特殊官能结构的聚合物。这个体系中的反应均互不干扰,有着良好的匹配效果。因此,得到的产物具有可控的分子量和很窄的分子量分布。与传统方法相比,这种多组分聚合体系节省了反应时间、降低了合成成本、合成途径更加绿色经济。我们现已发展了多种多组分聚合体系,按照复杂程度不同分为二元、三元和四元体系。通过不同的有机小分子反应与可控聚合的结合,我们成功制备了一些通过其他聚合方法难以或是无法合成的新型聚合物,体现了这一聚合方法的特点和优势。随着对多组分聚合体系认识的不断深入,相信我们能够更简便地合成更多结构新颖的聚合物。     

Multicomponent diffusion in nanosystems

We present the detailed analysis of the diffusive transport of spatially inhomogeneous fluid mixtures and the interplay between structural and dynamical properties varying on the atomic scale. The present treatment is based on different areas of liquid state theory, namely, kinetic and density functional theory and their implementation as an effective numerical method via the lattice Boltzmann approach. By combining the first two methods, it is possible to obtain a closed set of kinetic equations for the singlet phase space distribution functions of each species. The interactions among particles are considered within a self-consistent approximation and the resulting effective molecular fields are analyzed. We focus on multispecies diffusion in systems with short-range hard-core repulsion between particles of unequal sizes and weak attractive long-range interactions. As a result, the attractive part of the potential does not contribute explicitly to viscosity but to diffusivity and the thermodynamic properties. Finally, we obtain a practical scheme to solve the kinetic equations by employing a discretization procedure derived from the lattice Boltzmann approach. Within this framework, we present numerical data concerning the mutual diffusion properties both in the case of a quiescent bulk fluid and shear flow inducing Taylor dispersion.     

Multicomponent copolymerization on display

Potentialities of the employment of the software modeling tool “Copolymerization for Windows” developed by us for the calculation of statistical characteristics of chemical structure of multicomponent copolymers as well as for the prediction of their transparency and thermostability are exemplified by terpolymerization of styrene, methyl methacrylate and acrylonitrile.