埃罗替尼的合成

以N,N-二甲基甲酰胺和硫酸二甲酯反应生成的亚胺盐与3-乙炔基苯胺进行亲核反应及甲醇的消去,获得了制备埃罗替尼所需的重要中间体N’-(3-乙炔基苯基)-N,N-二甲基甲脒,收率为75.8%。再以此中间体与2-氨基-4,5-二(2-甲氧基乙氧基)苯甲腈通过Dimroth重排反应方便地制得了抗肿瘤药物埃罗替尼,总收率(以3-乙炔基苯胺计)为56.5%。与以往合成埃罗替尼的方法相比,该方法更经济、更绿色。     

Experimental and Kinetic Modeling Study of Methanol Ignition and Oxidation at High Pressure

A detailed chemical kinetic model for oxidation of CH₃OH at high pressure and intermediate temperatures has been developed and validated experimentally. Ab initio calculations and Rice–Ramsperger–Kassel–Marcus/transition state theory (RRKM/TST) analysis were used to obtain rate coefficients for , , , and . The experiments, involving CH₃OH/O₂ mixtures diluted in N₂, were carried out in a high‐pressure flow reactor at 600–900 K and 20–100 bar, varying the reaction stoichiometry from very lean to fuel‐rich conditions. Under the conditions studied, the onset temperature for methanol oxidation was not dependent on the stoichiometry, whereas increasing pressure shifted the ignition temperature toward lower values. Model predictions of the present experimental results, as well as rapid compression machine data from the literature, were generally satisfactory. The governing reaction pathways have been outlined based on calculations with the kinetic model. Unlike what has been observed for unsaturated hydrocarbons, the oxidation pathways for CH₃OH under the investigated conditions were very similar to those prevailing at higher temperatures and lower pressures. At the high pressures, the modeling predictions for onset of reaction were particularly sensitive to the reaction.     

Metal-based anticancer agents: targeting androgen-dependent and androgen-independent prostate and COX-positive pancreatic cancer cells by phenanthrenequinone semicarbazone and its metal complexes

A planar, polycyclic and aromatic hydrocarbon ligand, namely 9,10-phenanthrenequinone semicarbazone, and its transition metal complexes have been synthesized and structurally characterized. The in vitro antiproliferative activity of these compounds against five human cancer cell lines revealed that they were effective against androgen receptor-positive/negative prostate cancer cells as well as COX-positive pancreatic BxPC-3 cancer cell line. The driving force behind such antiproliferative activity seems to be the up-regulated COX expression in these cells, which was amenable for targeting through metal complexation. These structural motifs can, therefore, serve as a starting point for developing novel cytotoxic agents against the growing number of prostate and pancreatic cancers.     

Single‐Molecule Detection Reveals Knot Sliding in TrmD Denaturation

An increasing number of proteins are found to contain a knot in their polypeptide chain. Although some studies have looked into the folding mechanism of knotted proteins, why and how these complex topologies form are still far from being fully answered. Moreover, no experimental information about how the knot moves during the protein‐folding process is available. Herein, by combining single‐molecule fluorescence resonance energy transfer (smFRET) experiments with molecular dynamics (MD) simulations, we performed a detailed study to characterize the knot in the denatured state of TrmD, a knotted tRNA (guanosine‐1) methyltransferase from Escherichia coli, as a model system. We found that the knot still existed in the unfolded state of TrmD, consistent with the results for two other knotted proteins, YibK and YbeA. More interestingly, both smFRET experiments and MD simulations revealed that the knot slid towards the C‐terminal during the unfolding process, which could be explained by the relatively strong interactions between the β‐sheet core at the N terminal of the native knot region. The size of the knot in the unfolded state is not larger than that in the native state. In addition, the knot slid in a “downhill” mode with simultaneous chain collapse in the denatured state.     

Syntheses and Properties of Graphyne Fragments: Trigonally Expanded Dehydrobenzo[12]annulenes

We present herein the synthesis and properties of the largest hitherto unknown graphyne fragment, namely trigonally expanded tetrakis(dehydrobenzo[12]annulene)s (tetrakis‐DBAs). Intramolecular three‐fold alkyne metathesis reactions of hexakis(arylethynyl)DBAs 9 a and 9 b using Fürstner’s Mo catalyst furnished tetrakis‐DBAs 8 a and 8 b substituted with tert‐butyl or branched alkyl ester groups in moderate and fair yields, respectively, demonstrating that the metathesis reaction of this protocol is a powerful tool for the construction of graphyne fragment backbones. For comparison, hexakis(arylethynyl)DBAs 9 c – g have also been prepared. The one‐photon absorption spectrum of tetrakis‐DBA 8 a bearing tert‐butyl groups revealed a remarkable bathochromic shift of the absorption cut‐off (λ_cutoff) compared with those of previously reported graphyne fragments due to extended π‐conjugation. Moreover, in the two‐photon absorption spectrum, 8 a showed a large cross‐section for a pure hydrocarbon because of the planar para‐phenylene‐ethynylene conjugation pathways. Hexakis(arylethynyl)‐DBAs 9 c – e and 9 g and tetrakis‐DBA 8 b bearing electron‐withdrawing groups aggregated in chloroform solutions. Comparison between the free energies of 9 e and 8 b bearing the same substituents revealed the more favorable association of the latter due to stronger π–π interactions between the extended π‐cores. Polarized optical microscopy observations, DSC, and XRD measurements showed that 8 b and 9 e with branched alkyl ester groups displayed columnar rectangular mesophases. By the time‐resolved microwave conductivity method, the columnar rectangular phase of 8 b was shown to exhibit a moderate charge‐carrier mobility of 0.12 cm² V^?1 s^?1. These results indicate that large graphyne fragments can serve as good organic semiconductors.     

Facile Synthesis and Thermoelectric Properties of Self‐assembled Bi2Te3 One‐Dimensional Nanorod Bundles

Self‐assembled Bi₂Te₃ one‐dimensional nanorod bundles have been fabricated by a low‐cost and facile solvothermal method with ethylene diamine tetraacetic acid as an additive. The phase structures and morphologies of the samples were characterized by X‐ray diffraction, scanning electron microscopy, Fourier‐transform infrared spectrometry, and transmission electron microscope measurements. The growth mechanisms have been proposed based on the experimental results. The full thermoelectric properties of the nanorod bundles have been characterized and show a large improvement in the thermal conductivity attributed to phonon scattering of the nanostructures and then enhance the thermoelectric figure of merit. This work is promising for the realization of new types of highly efficient thermoelectric semiconductors by this method.     

Surfactant Hydrogels for the Dispersion of Carbon‐Nanotube‐Based Catalysts

Novel hydrogel phases based on positively charged and zwitterionic surfactants, namely, N‐[p‐(n‐dodecyloxybenzyl)]‐N,N,N‐trimethylammonium bromide (pDOTABr) and p‐dodecyloxybenzyldimethylamine oxide (pDOAO), which combine pristine carbon nanotubes (CNTs), were obtained, thus leading to stable dispersions and enhanced cross‐linked networks. The composite hydrogel featuring a well‐defined nanostructured morphology and an overall positively charged surface was shown to efficiently immobilise a polyanionic and redox‐active tetraruthenium‐substituted polyoxometalate (Ru₄POM) by complementary charge interactions. The resulting hybrid gel has been characterised by electron microscopy techniques, whereas the electrostatic‐directed assembly has been monitored by means of fluorescence spectroscopy and ζ‐potential tests. This protocol offers a straightforward supramolecular strategy for the design of novel aqueous‐based electrocatalytic soft materials, thereby improving the processability of CNTs while tuning their interfacial decoration with multiple catalytic domains. Electrochemical evidence confirms that the activity of the catalyst is preserved within the gel media.     

Synthesis of antibacterial cellulose materials using a “clickable” quaternary ammonium compound

Development of advanced functional materials from naturally abundant polymers such as cellulose are of significant importance. Of particular interest is embedding antibacterial functionality to cellulose materials to make permanent antibacterial materials and devices. In the present research, a “clickable” quaternary ammonium compound, N-(2-ethoxy-2-oxoethyl)-N,N-dimethylprop-2yn-1-aminium bromide (EdMPABr) was synthesized via a simple reaction with nearly stoichiometric yield and well characterized with 1D (¹H, ¹³C) and 2D (COSY, HSQC) NMR and ATR-FTIR. EdMPABr can be covalently bonded to many molecules containing an azido group to form non-leaching antibacterial materials via the simple Cu(I)-catalyzed alkyne-azide [2 + 3] cycloaddition reaction. As an example, EdMPABr was attached to our previously reported 3-O-azidopropoxypoly(ethylene glycol)-2,6-di-O-thexyldimethylsilyl cellulose (3-N₃PEG-2,6-TDMS cellulose, DS = 0.54 at C3 determined by ¹H NMR). Significant antibacterial activity of the synthesized 3-O-quaternary ammonium-2,6-di-O-thexyldimethylsilyl cellulose (3-QA-2,6-TDMS cellulose, DS = 0.30 at C3 determined by using N content from elemental analysis) was confirmed by testing against the representative bacteria Escherichia coli. By linking the EdMPABr to the honeycomb film of 3-N₃PEG-2,6-TDMS cellulose, the formed honeycomb film exhibited both antibacterial and antifouling properties. This research provides a simple and robust route towards the development of permanent antibacterial materials and biomedical devices.