Collective Total Synthesis of Englerin A and B,Orientalol E and F,and Oxyphyllol: Application of the Organocatalytic [4+3] Cycloaddition Reaction

The concise collective total synthesis of englerin A and B, orientalol E and F, and oxyphyllol has been accomplished in 10–15 steps, with the total synthesis of orientalol E and oxyphyllol being achieved for the first time. The success obtained was enabled by the realization of the [4+3] cycloaddition reaction of 9 and 10 . Other features of the synthesis include 1) the intramolecular Heck reaction to access the azulene core, 2) the epoxidation–S_N2′ reduction sequence to access the allylic alcohol, 3) the efficient regioselective and stereoselective formal hydration of the bridging C?C bond in the synthesis of englerins, and 4) the late‐stage chemo‐ and stereoselective C? H oxidation in the synthesis of orientalol E. The total synthesis of these natural products has enabled the structural revision of oxyphyllol and established the absolute stereochemical features of the organocatalytic [4+3] cycloaddition reaction. The identification of 5 as the natural product oxyphyllol, the success in converting 5 to orientalol E, along with the fact that englerins and oxyphyllol were isolated from plants of the same genus Phyllanthus gives support to our proposed biosynthetic pathways. This work may enable detailed biological evaluations of these natural products and their analogues and derivatives, especially of their potential in the fight against renal cell carcinoma (RCC).     

Direct grafting modification of pulp in ionic liquids and self-assembly behavior of the graft copolymers

In this paper, a novel biodegradable biomass-based amphiphile was prepared by direct grafting copolymerization of dissolved pulp with hydrophobic poly (l-lactide) in ionic liquids BmimCl. The molecular structures of the obtained copolymers were confirmed with ¹H-NMR, ¹³C-NMR and 2D HSQC NMR, and their physical properties were studied by TGA and XRD analysis. The self-assembly behaviors of these amphiphilies in aqueous solution was characterized by fluorescence spectrum and their critical micelle concentrations (CMC) were determined to be in the range of 0.326–0.062 mg/mL. TEM observations and DLS analysis revealed that the pulp-derived micelles had spherical and uniform morphology and small diameters (25–125 nm). It was also found that the surface tension of these copolymers solution firstly decreased dramatically with increasing concentration and then approached to a plateau value when the concentration was above their CMC value. MTT assay showed that the pulp-derived amphiphilic micelles exhibited good biocompatibility, which informed that these micelles could be expected to be used in biological regions, especially for the hydrophobic drug delivery system.     

基于FCS的海水痕量元素的通用测定平台

为了对海水痕量营养盐与重金属进行测定,基于FCS的设计思想,采用流动注射分光光度法研制了具有自适应外界设备、快速组建多种仪器及全数字化通信等特点的软硬件一体化的通用测定平台。平台以ARM(S3C2416)处理器为核心,Linux为操作系统,LCD作为人机交互显示,触摸屏或者USB鼠标完成输入控制,构成完整的嵌入式工控机系统;采用CAN总线并制定CAN应用层协议管理设备,提高了系统的可靠性及抗干扰能力。实际测试和应用证明,该平台自动化程度高,通用性、重用性及可扩展性均较强,可组建成亚硝氮、硝氮、氨氮、活性磷、铁等多种痕量元素的实验室、船载和原位分析系统,检测限为nmol/L级别。平台对样品的测试准确度与商品专用仪器无显著性差异。     

High‐Order Soliton Solution of Landau–Lifshitz Equation

The Landau–Lifshitz equation is analyzed via the inverse scattering method. First, we give the well‐posedness theory for Landau–Lifshitz equation with the frame of inverse scattering method. The generalized Darboux transformation is rigorous considered in the frame of inverse scattering transformation. Finally, we give the high‐order soliton solution formula of Landau–Lifshitz equation and vortex filament equation.     

Interactions of delta shock waves for the relativistic Chaplygin Euler equations with split delta functions

In this article, we are concerned with the interactions of delta shock waves with contact discontinuities for the relativistic Euler equations for Chaplygin gas by using split delta functions method. The solutions are obtained constructively and globally when the initial data consists of three piecewise constant states. The global structure and large time‐asymptotic behaviors of the solutions are analyzed case by case. During the process of the interaction, the strengths of delta shock waves are computed completely. Moreover, it can be found that the Riemann solutions are stable for such small perturbations with special initial data by letting perturbed parameter ε tends to zero. Copyright © 2014 John Wiley & Sons, Ltd.     

On Gradient Solitons of the Ricci–Harmonic Flow

In this paper, we study gradient solitons to the Ricci flow coupled with harmonic map heat flow. We derive new identities on solitons similar to those on gradient solitons of the Ricci flow. When the soliton is compact, we get a classification result. We also discuss the relation with quasi-Einstein manifolds.     

Hausdorff operators on the Heisenberg group

This paper is devoted to the high-dimensional and multilinear Hausdorff operators on the Heisenberg group H n. The sharp bounds for the strong type(p, p)(1 ≤ p ≤∞) estimates of n-dimensional Hausdorff operators on H n are obtained. The sharp bounds for strong(p, p) estimates are further extended to multilinear cases. As an application, we derive the sharp constant for the multilinear Hardy operator on H n. The weak type(p, p)(1 ≤ p ≤∞) estimates are also obtained.     

Amarusine A,a new dioxaspiro[4.4]nonane derivative with a butyrolactone ring from Pleioblastus amarus

Amarusine A (1), a new polyketide derivative possessing an unusual dioxaspiro[4.4]nonane derivative with a butyrolactone ring, was isolated from the leaves of Pleioblastus amarus. The structure and absolute stereochemistry of compound 1 were rigorously determined using UV, IR, HRESIMS, and 1D and 2D NMR techniques and by comparing experimental and calculated electronic circular dichroism (ECD) spectra. Amarusine A (1) exhibits a good antioxidant activity for scavenging the DPPH radical. A possible biosynthetic pathway was postulated.     

Crystal Structures and Photoluminescence Properties of Zinc(II) and Cadmium(II) Coordination Polymers with “Y”‐Shaped Ligands

Three Zn^II and Cd^II complexes with Y‐shaped dicarboxylate ligands, namely [Zn(L₁)(2,2′‐bpy)₂(H₂O)] · 2H₂O ( 1 ), [Zn(L₁)(bpp)(H₂O)] ( 2 ), and [Cd(L₁)(H₂O)] · H₂O ( 3 ) [H₂L₁ = N‐phenyliminodiacetic acid, 2,2′‐bpy = 2,2′‐bipyridine, bpp = 1,3‐bis(4‐pyridyl)propane] were synthesized and characterized by elemental analysis, IR spectroscopy single‐crystal X‐ray diffraction, and thermogravimetric analyses. Compound 1 shows an hydrogen‐bonded 2D network, whereas compound 2 is an infinite 1D wavy chain structure, though O–H ··· O hydrogen‐bonded to form a 2D network. Compound 3 displays a 2D uninodal 3‐connected Shubnikov plane net with the point symbol of (4.8²). Moreover, the solid‐state such as thermal stabilities and fluorescence properties of 1 – 3 were also investigated.     

Tuning Structural Topologies of Two Cadmium(II) Coordination Polymers via Isomeric Dipyridyl Ligands: Syntheses,Crystal Structures,and Luminescent Properties

Abstract. Two new coordination polymers {[Cd₂(BDC)₂(3‐bpmp)(H₂O)₂] · 2H₂O}_n ( 1 ) and [Cd₂(BDC)₂(4‐bpmp)]_n ( 2 ) [H₂BDC = 5‐hydroxy‐isophthalic acid, 3‐bpmp = 1,4‐bis(3‐pyridylmethy)piperazine, and 4‐bpmp = 1,4‐bis(4‐pyridylmethy) piperazine] were synthesized via hydrothermal synthesis, and further characterized by IR spectroscopy, elemental analysis, XRD, and X‐ray crystallography. Complex 1 shows a two‐dimensional (4,4) sql topology and complex 2 features an 8‐connected hex topology. Moreover, the luminescent properties of complexes 1 and 2 were investigated in the solid state at room temperature.