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991.
Dr. James R. Frost Dr. Colin M. Pearson Prof. Thomas N. Snaddon Dr. Richard A. Booth Dr. Richard M. Turner Dr. Johan Gold Dr. David M. Shaw Prof. Matthew J. Gaunt Prof. Steven V. Ley 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(38):13261-13277
Since their isolation almost 20 years ago, the callipeltosides have been of long standing interest to the synthetic community owing to their unique structural features and inherent biological activity. Herein we present our full research effort that has led to the synthesis of these molecules. Key aspects of our final strategy include 1) synthesis of the C1–C9 pyran core ( 5 ) using an AuCl3‐catalysed cyclisation; 2) formation of C10–C22 vinyl iodide ( 55 ) by sequential bidirectional Stille reactions and 3) diastereoselective union of these advanced fragments by means of an alkenylzinc addition (d.r.=91:9 at C9). The common callipeltoside aglycon ( 4 ) was completed in a further five steps. Following this, all three sugar fragments were appended to provide the entire callipeltoside family. In addition to this, D ‐configured callipeltose B was synthesised and appended to the callipeltoside aglycon. The 1H NMR spectrum of this molecule was found to be significantly different to the natural isolate, further supporting our assignment of callipeltoside B ( 2 ). 相似文献
992.
993.
The Thermal Instability of 2,4 and 2,6‐N‐Alkylamino‐disubstituted and 2‐N‐Alkylamino‐substituted Nitrobenzenes in Weakly Alkaline Solution: sec‐Amino Effect
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Christopher Walczak Thomas J. Payne Colin B. Wade Matthew Yonkey Melissa Scheid Alec Badour Dilip K. Mohanty 《Journal of heterocyclic chemistry》2015,52(3):681-687
We report herein the preparation of two families of secondary amines by the reactions of two equivalents of monoamines with either 2,4 or 2,6‐difluoronitrobenzenes in N,N‐dimethylacetamide in the presence of anhydrous potassium carbonate, as precursors of biologically important nitric oxide donating N‐nitrosamines. In both instances, these compounds could be prepared in quantitative yield when the reaction temperature was held below 130°C. Above this reaction temperature, an unexpected cyclization reaction between the nitro and newly formed adjacent secondary amine group leads to the formation of benzimidazole or quinoxaline rings in low yields. Reasonable reaction mechanisms for the cyclization reaction are proposed. 相似文献
994.
Synthesis and Reactivity of a Neutral,Three‐Coordinate Platinum(II) Complex Featuring Terminal Amido Ligation
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Colin M. Kelly Doo‐Hyun Kwon Dr. Michael J. Ferguson Dr. Steven M. Bischof Dr. Orson L. Sydora Prof. Dr. Daniel H. Ess Prof. Dr. Mark Stradiotto Prof. Dr. Laura Turculet 《Angewandte Chemie (International ed. in English)》2015,54(48):14498-14502
A crystallographically characterized three‐coordinate, formally 14 electron PtII complex 1 featuring terminal amido ligation is reported. Computational analysis revealed relatively weak π donation from the amide lone pair to platinum and supports a 14‐electron assignment for 1 . Stoichiometric reactivity studies confirmed the viability of net O? H and C? H addition across, as well as isonitrile insertion into, the terminal platinum–amido linkage of 1 . 相似文献
995.
Dr. Luke J. O'Driscoll Dr. Xintai Wang Michael Jay Dr. Andrei S. Batsanov Dr. Hatef Sadeghi Prof. Colin J. Lambert Dr. Benjamin J. Robinson Prof. Martin R. Bryce 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(2):892-899
As the field of molecular-scale electronics matures and the prospect of devices incorporating molecular wires becomes more feasible, it is necessary to progress from the simple anchor groups used in fundamental conductance studies to more elaborate anchors designed with device stability in mind. This study presents a series of oligo(phenylene-ethynylene) wires with one tetrapodal anchor and a phenyl or pyridyl head group. The new anchors are designed to bind strongly to gold surfaces without disrupting the conductance pathway of the wires. Conductive probe atomic force microscopy (cAFM) was used to determine the conductance of self-assembled monolayers (SAMs) of the wires in Au–SAM–Pt and Au–SAM–graphene junctions, from which the conductance per molecule was derived. For tolane-type wires, mean conductances per molecule of up to 10−4.37 G0 (Pt) and 10−3.78 G0 (graphene) were measured, despite limited electronic coupling to the Au electrode, demonstrating the potential of this approach. Computational studies of the surface binding geometry and transport properties rationalise and support the experimental results. 相似文献
996.
997.
Vlasios Leontidis Jie Chen Lucien Baldas Stéphane Colin 《Heat and Mass Transfer》2014,50(8):1065-1080
A numerical procedure has been developed for modeling 2D thermal creep flows with Fluent®. Complete first order velocity slip, including thermal creep and walls curvature effects, as well as temperature jump, boundary conditions, are implemented via C routines. After validation on benchmark flows, the technique is used for designing a Knudsen pump with curved microchannels and it is demonstrated that this micropump can be efficient in the slip flow regime. 相似文献
998.
999.
An efficient palladium-catalyzed cross-coupling of indium homoenolate with aryl halide is described. The reactions proceeded efficiently in DMA at 100 °C to afford the desired products of β-aryl ketones in moderate to good yields. Various important functional groups including COR, COOR, CHO, CN, OH, and NO(2) can be well tolerated in the protocol. 相似文献
1000.
Ember SW Schulze H Ross AJ Luby J Khondoker M Giraud G Terry JG Ciani I Tlili C Crain J Walton AJ Mount AR Ghazal P Bachmann TT Campbell CJ 《Analytical and bioanalytical chemistry》2011,401(8):2549-2559
Hepatitis C virus (HCV) is a major cause of chronic liver disease and liver cancer, and remains a large health care burden to the world. In this study we developed a DNA microarray test to detect HCV RNA and a protein microarray to detect human anti-HCV antibodies on a single platform. A main focus of this study was to evaluate possibilities to reduce the assay time, as a short time-to-result (TTR) is a prerequisite for a point-of-care test. Significantly reducing hybridisation and washing times did not impair the assay performance. This was confirmed first using artificial targets and subsequently using clinical samples from an HCV seroconversion panel derived from a HCV-infected patient. We were able to reduce the time required for the detection of human anti-HCV antibodies to only 14 min, achieving nanomolar sensitivity. The protein microarray exhibited an analytical sensitivity comparable to that of commercial systems. Similar results were obtained with the DNA microarray using a universal probe which covered all different HCV genotypes. It was possible to reduce the assay time after PCR from 150 min to 16 min without any loss of sensitivity. Taken together, these results constitute a significant step forward in the design of rapid, microarray-based diagnostics for human infectious disease, and show that the protein microarray is currently the most favourable candidate to fill this role. 相似文献