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101.
Alexander J. Boddy Dominic P. Affron Christopher J. Cordier Emma L. Rivers Alan C. Spivey James A. Bull 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(5):1472-1476
Methods that provide rapid access to new heterocyclic structures in biologically relevant chemical space provide important opportunities in drug discovery. Here, a strategy is described for the preparation of 2,2‐disubstituted azetidines, pyrrolidines, piperidines, and azepanes bearing ester and diverse aryl substituents. A one‐pot rhodium catalyzed N–H insertion and cyclization sequence uses diazo compounds to stitch together linear 1,m‐haloamines (m=2–5) to rapidly assemble 4 ‐, 5 ‐, 6 ‐, and 7 ‐membered saturated nitrogen heterocycles in excellent yields. Over fifty examples are demonstrated, including examples with diazo compounds derived from biologically active compounds. The products can be functionalized to afford α,α‐disubstituted amino acids and applied to fragment synthesis. 相似文献
102.
Use of atmospheric pressure solids analysis probe time‐of‐flight mass spectrometry to screen for plasticisers in gaskets used in contact with foods
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103.
Jenny Halleröd Chrisitan Ekberg Ivan Kajan Emma Aneheim 《Journal of solution chemistry》2018,47(6):1021-1036
The two organic ligands 6,6′-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydrobenzo[1,2,4]triazin-3-yl)[2,2′]bipyridine (CyMe\(_{4}\)-BTBP) and tri-butyl phosphate (TBP) have previously been investigated in different diluents for use within recycling of used nuclear fuel through solvent extraction. The thermodynamic parameters, \(K_{\mathrm{S}}\), \(\Delta C_{p}\), \(\Delta H^{0}\) and \(\Delta S^{0}\), of the CyMe\(_{4}\)-BTBP solubility in three diluents (cyclohexanone, octanol and phenyl trifluoromethyl sulfone) mixed with TBP have been studied at 288, 298 and 308 K, both as pristine solutions and pre-equilibrated with 4 mol\(\cdot \)L\(^{-1}\) nitric acid. In addition, the amount of acid in the organic phase and density change after pre-equilibration have been measured. The solubility of CyMe\(_{4}\)-BTBP increases with an increased temperature in all systems, especially after acid pre-equilibration. This increased CyMe\(_{4}\)-BTBP solubility after pre-equilibration could be explained by acid dissolution into the solvent. Comparing the \(\Delta H^{0}\) and \(\Delta S^{0}\) calculated using \(\Delta C_{p}\) with the same parameters derived from a linear fit indicates temperature independence of all three thermodynamic systems. The change in enthalpy is positive in all solutions. 相似文献
104.
Jixin Qiao Petra Lagerkvist Ilia Rodushkin Susanna Salminen-Paatero Per Roos Syverin Lierhagen Karl Andreas Jensen Emma Engstrom Yann Lahaye Lindis Skipperud 《Journal of Radioanalytical and Nuclear Chemistry》2018,315(3):565-580
Inductively coupled plasma mass spectrometry (ICP-MS) techniques are widely used for determination of long-lived radionuclides and their isotopic ratios in the nuclear fields. Uranium (U) and Plutonium (Pu) isotopes have been determined by many researchers with ICP-MS due to its relatively high sensitivity and short measurement time. In this work, an inter-laboratory comparison exercise among the Nordic countries was performed, focusing on the measurement of U and Pu isotopes in certified reference materials by ICP-MS. The performance and characters of different ICP-MS instruments are evaluated and discussed in this paper. 相似文献
105.
Rondahl Stina Holmgren Pointurier Fabien Ahlinder Linnea Ramebäck Henrik Marie Olivier Ravat Brice Delaunay François Young Emma Blagojevic Ned Hester James R. Thorogood Gordon Nelwamondo Aubrey N. Ntsoane Tshepo P. Roberts Sarah K. Holliday Kiel S. 《Journal of Radioanalytical and Nuclear Chemistry》2018,315(2):395-408
Journal of Radioanalytical and Nuclear Chemistry - This work presents the results for identification of chemical phases obtained by several laboratories as a part of an international nuclear... 相似文献
106.
Total Synthesis of Tambromycin by Combining Chemocatalytic and Biocatalytic C−H Functionalization
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Dr. Xiao Zhang Emma King‐Smith Prof. Dr. Hans Renata 《Angewandte Chemie (International ed. in English)》2018,57(18):5037-5041
A combination of genomic and metabolomic approaches recently resulted in the identification of a nonribosomal tetrapeptide tambromycin, which possesses promising antiproliferative activity and several unusual structural features, including a densely substituted indole, a methyloxazoline ring, and an unusual pyrrolidine‐containing amino acid called tambroline. In this work, we identify a concise synthetic route to access tambromycin, which relies on the strategic use of biocatalytic and chemocatalytic C?H functionalization methods to prepare two key precursors to the natural product in an efficient and scalable manner. The success of our study highlights the benefits of applying the principles of biocatalytic retrosynthesis as well as C?H functionalization logic to the synthesis of complex molecular scaffolds. 相似文献
107.
John T. Gupton Alex Shimozono Evan Crawford Joe Ortolani Evan Clark Matt Mahoney Campbell Heese Jeffrey Noble Carlos Perez Mandry Rene Kanters Raymond N. Dominey Emma W. Goldman James A. Sikorski Daniel C. Fisher 《Tetrahedron》2018,74(21):2650-2663
Highly functionalized pyrroles with appropriate regiochemical functionality represent an important class of marine natural products and potential drug candidates. We describe herein a detailed study of the reaction of α-aminoacid esters with vinylogous amides and also β-halovinylaldehydes for the regiospecific synthesis of 2,3,4-trisubstituted and 1,2,3,4-tetrasubstituted pyrroles. Since the vinylogous amides and β-halovinylaldehydes are readily available precursors, rapid access to a wide variety of unsymmetrically substituted pyrroles is accomplished via this methodology. 相似文献
108.
A novel approach to the valuable quaternary 3-aminooxindole skeleton is reported on the basis of intramolecular arylation of enolates of substituted amino acids. The reaction tolerates dialkyl- and arylalkylamines as well as a range of carbon substituents (primary and secondary alkyl, aryl). The cyclization of N-indolyl-substituted substrates is accompanied by direct C-H arylation of the indole, leading to indolo-fused benzodiazepines. 相似文献
109.
How to confirm identified toxicants in effect-directed analysis 总被引:1,自引:0,他引:1
Brack W Schmitt-Jansen M Machala M Brix R Barceló D Schymanski E Streck G Schulze T 《Analytical and bioanalytical chemistry》2008,390(8):1959-1973
Due to the production and use of a multitude of chemicals in modern society, waters, sediments, soils and biota may be contaminated
with numerous known and unknown chemicals that may cause adverse effects on ecosystems and human health. Effect-directed analysis
(EDA), combining biotesting, fractionation and chemical analysis, helps to identify hazardous compounds in complex environmental
mixtures. Confirmation of tentatively identified toxicants will help to avoid artefacts and to establish reliable cause–effect
relationships. A tiered approach to confirmation is suggested in the present paper. The first tier focuses on the analytical
confirmation of tentatively identified structures. If straightforward confirmation with neat standards for GC–MS or LC–MS
is not available, it is suggested that a lines-of-evidence approach is used that combines spectral library information with
computer-based structure generation and prediction of retention behaviour in different chromatographic systems using quantitative
structure–retention relationships (QSRR). In the second tier, the identified toxicants need to be confirmed as being the cause
of the measured effects. Candidate components of toxic fractions may be selected based, for example, on structural alerts.
Quantitative effect confirmation is based on joint effect models. Joint effect prediction on the basis of full concentration–response
plots and careful selection of the appropriate model are suggested as a means to improve confirmation quality. Confirmation
according to the Toxicity Identification Evaluation (TIE) concept of the US EPA and novel tools of hazard identification help
to confirm the relevance of identified compounds to populations and communities under realistic exposure conditions. Promising
tools include bioavailability-directed extraction and dosing techniques, biomarker approaches and the concept of pollution-induced
community tolerance (PICT).
Figure Toxicity confirmation in EDA as a tiered approach 相似文献
110.
Aileen M. Eagleton Emma K. Ambrogi Sophia A. Miller Dr. Nataliia Vereshchuk Prof. Katherine A. Mirica 《Angewandte Chemie (International ed. in English)》2023,62(49):e202309078
Owing to high modularity and synthetic tunability, metal–organic frameworks (MOFs) on textiles are poised to contribute to the development of state-of-the-art wearable systems with multifunctional performance. While these composite materials have demonstrated promising functions in sensing, filtration, detoxification, and biomedicine, their applicability in multifunctional systems is only beginning to materialize. This review highlights the multifunctionality and versatility of MOF-integrated textile systems. It summarizes the operational goals of MOF@textile composites, encompassing sensing, filtration, detoxification, drug delivery, UV protection, and photocatalysis. Building upon these recent advances, this review concludes with an outlook on emerging opportunities for the diverse applications of MOF@textile systems in the realm of smart wearables. 相似文献