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排序方式: 共有47条查询结果,搜索用时 203 毫秒
1.
Daniel Townsend Prof. Dr. Kenneth Shankland Dr. Alex Weymouth-Wilson Dr. Zofia Komsta Dr. Tim Evans Dr. Alexander J. A. Cobb 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(16):3504-3508
A highly enantioselective, organocatalytic, and scalable synthesis of a very unusual cis-decalin-cis-hydrindane tricyclic diterpenoid system has been achieved. Despite the prevalent pharmacological space that the related trans,trans and trans,cis-systems occupy, there have been no reports of an asymmetric synthesis of the cis,cis systems in the literature until now. We demonstrate the flexibility of our approach not only through access to a diverse range of products, all of which are attained in exceptionally high selectivities, but also by showing their easy conversion to the corresponding trans,cis-system and other derivatives. 相似文献
2.
Dr. Paul Smart Dr. Charles A. Mason Jason R. Loader Dr. Anthony J. H. M. Meijer Prof. Alastair J. Florence Dr. Kenneth Shankland Dr. Ashleigh J. Fletcher Dr. Stephen P. Thompson Dr. Michela Brunelli Dr. Adrian H. Hill Prof. Lee Brammer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(11):3552-3557
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Antonio Dell'Isola Dr. Matthew M. W. McLachlan Dr. Benjamin W. Neuman Hawaa M. N. Al‐Mullah Alexander W. D. Binks Warren Elvidge Dr. Kenneth Shankland Dr. Alexander J. A. Cobb 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(37):11685-11689
An efficient synthesis of spirocyclic triazolooxazine nucleosides is described. This was achieved by the conversion of β‐D ‐psicofuranose to the corresponding azido‐derivative, followed by alkylation of the primary alcohol with a range of propargyl bromides, obtained by Sonogashira chemistry. The products of these reactions underwent 1,3‐dipolar addition smoothly to generate the protected spirocyclic adducts. These were easily deprotected to give the corresponding ribose nucleosides. The library of compounds obtained was investigated for its antiviral activity using MHV (mouse hepatitis virus) as a model wherein derivative 3 f showed the most promising activity and tolerability. 相似文献
4.
Asllani I Shankland E Pratum T Kushmerick M 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2003,163(1):124-132
In this study we tested the effect of molecular charge and chirality as well as tissue pH on dipolar coupling interaction in skeletal muscle. These results were demonstrated by double quantum filtered, DQF, 1H NMR spectra acquired on permeable skeletal muscle samples dialyzed against buffered solutions containing three classes of solutes-electrolytes (lactate and Tris), zwitterions (alanine and glycine), and non-electrolytes (dioxane and ethanol)-as a function of pH ranging from 5.0 to 8.5. The results show that charge density on the protein filaments strongly influences dipolar coupling of solutes in muscle whereas charge on the solutes themselves has only a small effect. The frequency splitting of the dipolar coupled peaks for all the molecules tested was strongly affected by muscle pH. Higher pH increased negative charge density on the filaments and resulted in weaker dipolar coupling for anions and zwitterions but stronger coupling for the cation TRIS. Molecular charge per se or chirality did not affect the frequency splitting of the dipolar coupled peaks. The molecules, lactate, ethanol, and alanine, have scalar coupled spins and consequently a double quantum signal in solution. However, spectra acquired from these molecules in muscle showed an additional frequency splitting due to additional dipolar coupling interactions. Due to lack of scalar coupling, spectra from Tris, glycine, and dioxane showed no double quantum signal in solution but did when in muscle. All these observations can be explained by the fact that the net charge on protein filaments dominates the mechanism of dipolar coupling interactions in the highly anisotropic structures in muscle. 相似文献
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Espallargas GM Hippler M Florence AJ Fernandes P van de Streek J Brunelli M David WI Shankland K Brammer L 《Journal of the American Chemical Society》2007,129(50):15606-15614
Hydrogen chloride gas (HCl) is absorbed (and reversibly released) by a nonporous crystalline solid, [CuCl2(3-Clpy)2] (3-Clpy = 3-chloropyridine), under ambient conditions leading to conversion from the blue coordination compound to the yellow salt (3-ClpyH)2[CuCl4]. These reactions require substantial motions within the crystalline solid including a change in the copper coordination environment from square planar to tetrahedral. This process also involves cleavage of the covalent bond of the gaseous molecules (H-Cl) and of coordination bonds of the molecular solid compound (Cu-N) and formation of N-H and Cu-Cl bonds. These reactions are not a single-crystal-to-single-crystal transformation; thus, the crystal structure determinations have been performed using X-ray powder diffraction. Importantly, we demonstrate that these reactions proceed in the absence of solvent or water vapor, ruling out the possibility of a water-assisted (microscopic recrystallization) mechanism, which is remarkable given all the structural changes needed for the process to take place. Gas-phase FTIR spectroscopy has permitted us to establish that this process is actually a solid-gas equilibrium, and time-resolved X-ray powder diffraction (both in situ and ex situ) has been used for the study of possible intermediates as well as the kinetics of the reaction. 相似文献
7.
Robert Dinnebier Hans‐Wolfram Lerner Li Ding Kenneth Shankland William I. F. David Peter W. Stephens Matthias Wagner 《无机化学与普通化学杂志》2002,628(1):310-314
The purple colored coordination polymer [1 Cu]n was obtained from 2,5‐bis(pyrazol‐1‐yl)‐1,4‐dihydroxybenzene and CuBr2 in aqueous ammonia. The crystal structure of [1 Cu]n was determined from high resolution X‐ray powder diffraction data using the method of simulated annealing. In the solid state, [1 Cu]n features largely independent linear chains, all of them being oriented parallel to the c‐axis of the crystal. The Cu ions are coordinated in a square‐planar fashion by two nitrogen atoms and two anionic oxygen donors. Magnetic susceptibility and magnetization measurements indicate the Cu ions in [1 Cu]n to be antiferromagnetically coupled with a coupling constant of about 20 K. 相似文献
8.
The proton and carbon-13 NMR spectra of 2,3,6 -tri-O-methyl-β-cyclodextrin in deuteriochloroform have been fully and unambiguously assigned using homonuclear and selective heteronuclear spin decoupling and two-dimensional homo- and heteronudear correlation NMR spectroscopy. Corrections are made to some earlier literature assignments. 相似文献
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