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991.
Christina Zalaru Mino R. Caira Mircea Iovu Elena Cristea 《Journal of chemical crystallography》2007,37(9):623-628
Abstract X-ray structures of three pharmacologically active lidocaine analogs, containing a common, substituted pyrazole moiety as
the basic residue and variously substituted phenyl rings as the hydrophobic residue, have been determined. This isomeric series
comprises 2-(3,5-dimethyl-pyrazol-1-yl)-2′-methylacetanilide (1), 2-(3,5-dimethyl-pyrazol-1-yl)-3′-methylacetanilide monohydrate (2), and 2-(3,5-dimethyl-pyrazol-1-yl)-4′-methylacetanilide (3). Crystal data are 1: space group P2
1
/c with a = 4.7617(2), b = 11.5638(4), c = 23.603(1) ?, β = 90.736(2)°, Z = 4; 2: P2
1
/c with a = 4.7260(1), b = 13.7001(4), c = 21.7006(6) ?, β = 93.425(1)°, Z = 4; 3: P2
1
/n with a = 6.4103(3), b = 24.584(1), c = 8.4449(4) ?, β = 100.273(3)°, Z = 4. In 1–3, the amide bond is trans-planar but the basic and hydrophobic residues adopt different orientations relative to this plane. Hydrogen bonding in 1 and 3 is based on C(4) linear arrays whereas in the monohydrate 2, the presence of water gives rise to R
4
4
(16) ring motifs. A summary of the local anesthetic and anti-arrhythmic properties of 1–3 is provided.
Graphical abstract
X-ray Structures of Pharmacologically Active 2-(3,5-Dimethyl-pyrazol-1-yl)-methylacetanilides
Christina Zalaru, Mino R. Caira, Mircea Iovu, and Elena Cristea
The title compounds are lidocaine analogs that display local anesthetic and anti-arrhythmic activities. X-ray analyses revealed
a range of solid-state conformations among these isomeric compounds as well as variation in hydrogen bonding schemes, namely
C(4) (R = o-, p-CH3) and R44(16) (R = m-CH3, monohydrate crystal).
1,1-Os3(CO)9(μ-CO)(phen) 相似文献
992.
Volker C. Kirsch Christina Orgler Simone Braig Irmela Jeremias David Auerbach Rolf Müller Angelika M. Vollmar Stephan A. Sieber 《Angewandte Chemie (International ed. in English)》2020,59(4):1595-1600
Novel targets are needed for treatment of devastating diseases such as cancer. For decades, natural products have guided innovative therapies by addressing diverse pathways. Inspired by the potent cytotoxic bioactivity of myxobacterial vioprolides A–D, we performed in‐depth studies on their mode of action. Based on its prominent potency against human acute lymphoblastic leukemia (ALL) cells, we conducted thermal proteome profiling (TPP) and deciphered the target proteins of the most active derivative vioprolide A (VioA) in Jurkat cells. Nucleolar protein 14 (NOP14), which is essential in ribosome biogenesis, was confirmed as a specific target of VioA by a suite of proteomic and biological follow‐up experiments. Given its activity against ALL cells compared to healthy lymphocytes, VioA exhibits unique therapeutic potential for anticancer therapy through a novel mode of action. 相似文献
993.
Curtis J. Czerwinski Ilia A. Guzei Tanya J. Cordes Kevin M. Czerwinski Nevin A. Mlodik 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(12):m499-m500
The title compound, [Cr(C12H9Br)(CO)3], crystallizes in the triclinic space group with close Br⋯Br separations. These contacts, along with several other factors, influence the (Ph)C—C(o‐BrC6H4) dihedral angle of 58.82 (6)°. The typical piano‐stool coordination about the Cr atom is in excellent agreement with the results of density functional theory calculations. 相似文献
994.
The stability of synchronous states is analyzed in the context of two populations of inhibitory and excitatory neurons, characterized by two different pulse-widths. The problem is reduced to that of determining the eigenvalues of a suitable class of sparse random matrices, randomness being a consequence of the network structure. A detailed analysis, which includes also the study of finite-amplitude perturbations, is performed in the limit of narrow pulses, finding that the overall stability depends crucially on the relative pulse-width. This has implications for the overall property of the asynchronous (balanced) regime.
相似文献995.
Hermann Neitz Niels Benjamin Paul Florian R. Hge Christina Lindner Roman Graebner Michael Kovermann Franziska Thomas 《Chemical science》2022,13(31):9079
β-Sheet motifs such as the WW domain are increasingly being explored as building blocks for synthetic biological applications. Since the sequence-structure relationships of β-sheet motifs are generally complex compared to the well-studied α-helical coiled coil (CC), other approaches such as combinatorial screening should be included to vary the function of the peptide. In this study, we present a combinatorial approach to identify novel functional mini-proteins based on the WW-domain scaffold, which takes advantage of the successful reconstitution of the fragmented WW domain of hPin1 (hPin1WW) by CC association. Fragmentation of hPin1WW was performed in both loop 1 (CC-hPin1WW-L1) and loop 2 (CC-hPin1WW-L2), and the respective fragments were linked to the strands of an antiparallel heterodimeric CC. Structural analysis by CD and NMR spectroscopy revealed structural reconstitution of the WW-domain scaffold only in CC-hPin1WW-L1, but not in CC-hPin1WW-L2. Furthermore, by using 1H–15N HSQC NMR, fluorescence and CD spectroscopy, we demonstrated that binding properties of fragmented hPin1WW in CC-hPin1WW-L1 were fully restored by CC association. To demonstrate the power of this approach as a combinatorial screening platform, we synthesized a four-by-six library of N- and C-terminal hPin1WW-CC peptide fragments that was screened for a WW domain that preferentially binds to ATP over cAMP, phophocholine, or IP6. Using this screening platform, we identified one WW domain, which specifically binds ATP, and a phosphorylcholine-specific WW-based mini-receptor, both having binding dissociation constants in the lower micromolar range.A combinatorial approach toward novel functional WW domains based on coiled-coil-mediated reconstitution of split WW domains is presented. As such, an ATP-binding WW domain was found from a 4-by-6 library of N- and C-terminal WW domain fragments. 相似文献
996.
Natasa P. Kalogiouri Christina Karadimou Mary S. Avgidou Elissavet Petsa Emmanouil-Nikolaos Papadakis Serafeim Theocharis Ioannis Mourtzinos Urania Menkissoglu-Spiroudi Stefanos Koundouras 《Molecules (Basel, Switzerland)》2022,27(20)
A rapid and simple HPLC-DAD analytical method was developed and optimized for the determination of anthocynanins in three red Greek winegrape varieties (Kotsifali, Limnio, and Vradiano). The critical parameters, such as the acidifying solvent and the extraction temperature, which affect the extraction of anthocyanins from the grapes, were studied to find the optimum values. The developed methodology was validated in terms of selectivity, linearity, accuracy, and precision and presented satisfactory results. The limits of quantification (LOQs) ranged between 0.20 mg/kg to 0.60 mg/kg, and the limits of detection (LODs) ranged between 0.06 mg/kg and 0.12 mg/kg. The RSD% of the within-day and between-day assays were lower than 6.2% and 8.5%, respectively, showing adequate precision. The accuracy ranged between 91.6 and 119% for within-day assay and between 89.9 and 123% for between-day assay. Sixteen samples from the main regions of each variety as well as from the official ampelographic collections of Greece were collected during the 2020 growing season and were further analyzed by HPLC-DAD. Notable differences in the anthocyanin content were detected among the cultivars using hierarchical cluster analysis (HCA). 相似文献
997.
Costas Tsioptsias Christina Spartali Sotirios I. Marras Xanthi Ntampou Ioannis Tsivintzelis Costas Panayiotou 《Molecules (Basel, Switzerland)》2022,27(19)
Silybin is a complex organic molecule with high bioactivity, extracted from the plant Silybum. As a pharmaceutical substance, silybin’s bioactivity has drawn considerable attention, while its other properties, e.g., thermodynamic properties and thermal stability, have been less studied. Silybin has been reported to exhibit a melting point, and values for its heat of fusion have been provided. In this work, differential scanning calorimetry, thermogravimetry including derivative thermogravimetry, infrared spectroscopy, and microscopy were used to provide evidence that silybin exhibits a thermochemical transition, i.e., softening occurring simultaneously with decomposition. Data from the available literature in combination with critical discussion of the results in a general framework suggest that thermochemical transition is a broad effect exhibited by various forms of matter (small molecules, macromolecules, natural, synthetic, organic, inorganic). The increased formation of hydrogen bonding contributes to this behavior through a dual influence: (a) inhibition of melting and (b) facilitation of decomposition due to weakening of chemical bonds. 相似文献
998.
Jean-Noël Rebilly Christian Herrero Katell Snchal-David Rgis Guillot Tanya Inceoglu Hlne Maisonneuve Frdric Banse 《Chemical science》2021,12(47):15691
Redox metalloenzymes achieve very selective oxidation reactions under mild conditions using O2 or H2O2 as oxidants and release harmless side-products like water. Their oxidation selectivity is intrinsically linked to the control of the oxidizing species generated during the catalytic cycle. To do so, a second coordination sphere is used in order to create a pull effect during the activation of O2 or H2O2, thus ensuring a heterolytic O–O bond cleavage. Herein, we report the synthesis and study of a new non-heme FeII complex bearing a pentaazadentate first coordination sphere and a pendant phenol group. Its reaction with H2O2 generates the classical FeIIIOOH species at high H2O2 loading. But at low H2O2 concentrations, an FeIVO species is generated instead. The formation of the latter is directly related to the presence of the 2nd sphere phenol group. Kinetic, variable temperature and labelling studies support the involvement of the attached phenol as a second coordination sphere moiety (weak acid) during H2O2 activation. Our results suggest a direct FeII → FeIVO conversion directed by the 2nd sphere phenol via the protonation of the distal O atom of the FeII/H2O2 adduct leading to a heterolytic O–O bond cleavage.A new FeII complex with a phenol group attached as a second coordination sphere moiety activates H2O2 to yield FeIVO following a mechanism reminiscent of peroxidase enzymes. 相似文献
999.
Horst Kisch Ling Zang Christian Lange Wilhelm F. Maier Christina Antonius Dieter Meissner 《Angewandte Chemie (International ed. in English)》1998,37(21):3034-3036
Amorphous, microporous TiO 2 hybrid semiconductors modified with transition metals induce generation of a photocurrent and photocatalytic degradation of the water contaminant 4-chlorophenol through photoinduced charge separation (the postulated mechanism is shown in the picture, Ar=4-ClC6H4). In contrast to the previously known crystalline titania photocatalysts, which are active only when excited with UV light, the amorphous semiconductors modified with platinum, rhodium, and gold chloride enable both processes also with visible light. 相似文献
1000.
Gerhard Maier Christina Zech Brigitte Voit Hartmut Komber 《Macromolecular Symposia》2001,163(1):75-86
4‐Methoxy‐4′‐(3″‐N‐maleimidopropoxy)benzaldazine has been prepared and used for the synthesis of hyperbranched polymers by ,criss‐cross'‐cycloaddition. In this type of reaction two unsaturated groups, such as the maleic imide groups, are added to the azine function. Hence, the azine behaves as a difunctional system, and therefore 4‐Methoxy‐4′‐(3″‐N‐maleimidopropoxy)benz‐aldazine is an AB2 monomer, with the maleic imide group being the A‐function, and the azine group representing the B2 part. The nature of this cycloaddition reaction ensures the coupled reaction of the two B‐functions of each monomer unit. Consequently, the resulting polymer consists exclusively of branched and terminal repeating units and therefore has a degree of branching of 100%. 相似文献