Synthesis of 3‐Aminotropones from N‐Boc‐Protected Furan‐2‐amine (=tert‐Butyl Furan‐2‐ylcarbamate; Boc=(tert‐Butoxy)carbonyl) by Cycloaddition Reactions and Subsequent Rearrangement

The 3‐aminotropones (=3‐aminocyclohepta‐2,4,6‐trien‐1‐ones) 4 were prepared in two steps by i) a [4+3] cycloaddition reaction between a conveniently substituted α,α′‐dihalo ketone 1 and a furan‐2‐amine derivative 2 functionalized at C(2) by a protected amino group (→ 3 ), and ii) a base‐induced molecular rearrangement of the cycloadduct 3 via cleavage of the O‐bridge. A mechanism for the formation of 3‐aminotropones is proposed on the basis of the initial deprotonation of the [(tert‐butoxy)carbonyl]amino (BocNH) group of 3 , followed by O‐bridge opening, an acid–base equilibrium, and finally an alkoxyaluminate elimination to afford the conjugated stable troponoid system (Scheme 7).     

Squarato-metal(II) complexes. 2. unusual bonding mode for a squarato-bridged trinuclear copper(II) complex

Herein, we report the structural characterization and magnetic properties of the unique squarato-bridged-tricopper(II) complex, [Cu3(pmap)3(micro1,2,3-C4O4)](ClO4)(4).2H 2O (1), based on the tripod tripyridylamine ligand bis[2-(2-pyridyl)ethyl]-(2-pyridyl)methylamine (pmap). Each of the three copper centers is penta-coordinated by four N atoms of a pmap ligand and one bridging O atom of the central squarato dianion. This complex is the first example of a non-polymeric X-ray structurally characterized trimeric transition metal complex with the three metal cations being bridged by a single squarato ligand in a micro1,2,3 coordination mode. The magnetic properties of the complex were measured over the temperature range 2-300 K. The complex exhibits moderate bulk antiferromagnetic interaction. The three magnetic exchange pathways have J values of -27.8, -20.8, and -31.9 cm(-1). The DFT calculations corroborate the relatively strong antiferromagnetic couplings obtained from the fitting of the experimental magnetic susceptibility data and allow an assignment of the fitted J values. Several geometrical parameters have been analyzed using theoretical calculations to establish magnetostructural correlations for complex 1.     

Self-assembly of a chiral carbonate- and cytidine-containing dodecanuclear copper(II) complex: a multiarm-supplied globular capsule

A dodecanuclear copper(II) globular-shaped structure has been obtained with the cytidine nucleoside and the templating carbonate anion. It shows receptor properties through anion-cation and multiple anion-pi interactions toward ClO 4 (-) as well as an overall antiferromagnetic coupling.     

Optimization of steady state recycling parameters utilizing polarimetry in chiral separations

Processing gram to kilogram quantities of target analytes has led to the exploration of several high-throughput separation techniques. Among those investigated is steady state recycling (SSR). Similar to simulated moving bed (SMB) fractions are collected from the leading and trailing edges of a chromatographic profile while sample material is injected into the interior. Purifying large amounts of sample in the semi-preparative stage is ideal for these groups. SSR allows for development of methods capable of separating 50 g to kilograms and even greater amounts of product efficiently. Using polarimetry to optimize the SSR method further improves the efficiency of method development, providing comprehensive data leading to incisive development decisions. Accurate sample injection allowed continual 99% enantiomer separation after polarimetry optimization. We have developed an efficient SSR optimization methodology that offers rapid development of chiral separation by SSR.     

Three steps multiobjective decision process for software release planning

This paper deals with how to determine which features should be included in the software to be developed. Metaheuristic techniques have been applied to this problem and can help software developers when they face contradictory goals. We show how the knowledge and experience of human experts can be enriched by these techniques, with the idea of obtaining a better requirements selection than that produced by expert judgment alone. This objective is achieved by embedding metaheuristics techniques into a requirements management tool that takes advantage of them during the execution of the development stages of any software development project. © 2015 Wiley Periodicals, Inc. Complexity 21: 250–262, 2016     

Preparation of molecularly imprinted polymeric fibers using a single bifunctional monomer for the solid‐phase microextraction of parabens from environmental solid samples

In this study, molecularly imprinted polymer fibers for solid‐phase microextraction have been prepared with a single bifunctional monomer, N,O‐bismethacryloyl ethanolamine using the so‐called “one monomer molecularly imprinted polymers” method, replacing the conventional combination of functional monomer and cross‐linker to form high fidelity binding sites. For comparison, imprinted fibers were prepared following the conventional approach based on ethylene glycol dimethacrylate as cross‐linker and methacrylic acid as monomer. The recognition performance of the new fibers was evaluated in the solid‐phase microextraction of parabens, and from this study it was concluded that they provided superior performance over conventionally formulated fibers. Ultimately, real‐world environmental testing on spiked solid samples was successful by the molecularly imprinted solid‐phase microextraction of samples, and the relative recoveries obtained at enrichment levels of 10 ng/g of parabens were within 78–109% for soil and 83–109% for sediments with a relative standard deviation <15% (n = 3).     

Identification of Biomarkers of Necrosis in Xenografts Using Imaging Mass Spectrometry

Xenografts are commonly used to test the effect of new drugs on human cancer. However, because of their heterogeneity, analysis of the results is often controversial. Part of the problem originates in the existence of tumor cells at different metabolic stages: from metastatic to necrotic cells, as it happens in real tumors. Imaging mass spectrometry is an excellent solution for the analysis of the results as it yields detailed information not only on the composition of the tissue but also on the distribution of the biomolecules within the tissue. Here, we use imaging mass spectrometry to determine the distribution of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and their plasmanyl- and plasmenylether derivatives (PC-P/O and PE-P/O) in xenografts of five different tumor cell lines: A-549, NCI-H1975, BX-PC3, HT29, and U-87 MG. The results demonstrate that the necrotic areas showed a higher abundance of Na⁺ adducts and of PC-P/O species, whereas a large abundance of PE-P/O species was found in all the xenografts. Thus, the PC/PC-ether and Na⁺/K⁺ ratios may highlight the necrotic areas while an increase on the number of PE-ether species may be pointing to the existence of viable tumor tissues. Furthermore, the existence of important changes in the concentration of Na⁺ and K⁺ adducts between different tissues has to be taken into account while interpreting the imaging mass spectrometry results.

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Projections of self-similar sets with no separation condition

Two natural symplectic constructions, the Lagrangian suspension and Seidel’s quantum representation of the fundamental group of the group of Hamiltonian diffeomorphisms, Ham(M), with (M, ω) a monotone symplectic manifold, admit categorifications as actions of the fundamental groupoid Π(Ham(M)) on a cobordism category recently introduced in [BC14] and, respectively, on a monotone variant of the derived Fukaya category. We show that the functor constructed in [BC14] that maps the cobordism category to the derived Fukaya category is equivariant with respect to these actions.     

Biosynthesis of naphthylisoquinoline alkaloids: synthesis and incorporation of an advanced C2-labeled isoquinoline precursor

Biosynthetic studies on naphthylisoquinoline alkaloids involving a specifically [1,1′-¹³C₂]-labeled dihydroisoquinoline 7 are described. The synthesized precursor 7 was fed to callus cultures of Triphyophyllum peltatum and the isolated secondary metabolites were characterized by spectroscopic methods (¹H, ¹³C NMR, and INADEQUATE experiments). The unambiguous incorporation of the precursor into dioncophylline A and two minor naphthylisoquinolines, together with the formation of the labeled corresponding trans-configured tetrahydroisoquinoline, proves the implication of such advanced intermediates in the proposed biosynthetic pathway of naphthylisoquinoline alkaloids.     

A rare ferromagnetically coupled asymmetric doubly azido bridged copper(II) dimer with an N,N, O donor Schiff base

A new end-to-end (EE) doubly azido bridged dinuclear complex [Cu₂L₂(μ_1,3-N₃)₂] (1) [where L = (E)-4-(2-(dimethylamino)ethylimino)-1,1,1-trifluoropentan-2-one)] has been synthesized and characterized by elemental and spectroscopic techniques. Single crystal X-ray diffraction analysis reveals that the dimeric complex possesses a center of inversion. Each copper atom in 1 is in a distorted square pyramidal geometry with a CuN₄O chromophore as revealed from the τ value, 0.19. The four basal positions are occupied by two imine N and one keto O atom of the Schiff base and one N atom from the azide anion. Another N atom from a coordinated azide occupies the apical position. Temperature dependent magnetic susceptibility of 1 was fitted using the Bleaney–Bowers expression which led to the parameters J = 13.6 cm⁻¹ and R = 3.4 × 10⁻⁵. It indicates a ferromagnetic interaction through the double azido bridges connecting the individual copper Schiff base units.