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31.
Musah RA Vuong AL Henck C Shepard JR 《Journal of the American Society for Mass Spectrometry》2012,23(5):996-999
The spermicide nonoxynol-9 is actually a complex mixture of dozens of closely related amphiphilic compounds, and the chemical
properties of this assortment significantly hamper its characterization by GC-MS. The inability to perform routine GC-MS testing
on nonoxynol-9 has limited its evidentiary value in forensic casework, which relies heavily on this technique for analysis.
A disturbing trend in sexual assault is the use of condoms by assailants, to avoid leaving behind DNA evidence that can connect
a perpetrator to a victim. This observation necessitates the development of alternative methods for the analysis of trace
evidence that can show causal links between a victim and a suspect. Detection of lubricants associated with sexual assault
is one such way to establish this connection. The development of GC-MS methods that permit facile detection of both nonoxynol-9
alone and nonoxynol-9 extracted from other complex matrices that have potential as trace evidence in sexual assault is reported.
A detection limit of 2.14 μg of nonoxynol-9 is demonstrated, and a detailed mass spectral profile that elaborates on what
is known of its structure is provided. 相似文献
32.
Hien Vuong 《合成通讯》2019,49(2):316-323
Heterocyclic imines provide biaryl products by a two-step transformation. The first transformation involves a Diels–Alder reaction with a multiply protonated imine to give a tetrahydroquinoline product, whereas the second step involves oxidation with elemental sulfur at 260?°C. 相似文献
33.
Jeishla L. M. Matos Samantha A. Green Yuge Chun Vuong Q. Dang Russell G. Dushin Paul Richardson Jason S. Chen David W. Piotrowski Brian M. Paegel Ryan A. Shenvi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(31):13098-13103
Preparative reactions that occur efficiently under dilute, buffered, aqueous conditions in the presence of biomolecules find application in ligation, peptide synthesis, and polynucleotide synthesis and sequencing. However, the identification of functional groups or reagents that are mutually reactive with one another, but unreactive with biopolymers and water, is challenging. Shown here are cobalt catalysts that react with alkenes under dilute, aqueous, buffered conditions and promote efficient cycloisomerization and formal Friedel–Crafts reactions. The constraining conditions of bioorthogonal chemistry are beneficial for reaction efficiency as superior conversion at low catalyst concentration is obtained and competent rates in dilute conditions are maintained. Efficiency at high dilution in the presence of buffer and nucleobases suggests that these reaction conditions may find broad application. 相似文献
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Capon RJ Vuong D McNally M Peterle T Trotter N Lacey E Gill JH 《Organic & biomolecular chemistry》2005,3(1):118-122
The principle nematocidal agent present in a southern Australian marine sponge of the genus Echinodictyum has been isolated and identified as the novel betaine (+)-echinobetaine B (6), and the structure assigned by spectroscopic analysis has been confirmed by total synthesis. Preliminary SAR conclusions are drawn from analysis of synthetic intermediates and the known marine metabolites zooanemonin (12) and norzooanemonin (13), and the new sponge metabolite norzooanemonin methyl ester (14). The latter compound is reported for the first time from a selection of Australian sponges, including an Axinyssa sp., a Niphates sp., an Axinella sp. and a Ptilocaulis sp. 相似文献
36.
Vu T. Nguyen Graham C. Haug Viet D. Nguyen Ngan T. H. Vuong Hadi D. Arman Oleg V. Larionov 《Chemical science》2021,12(18):6429
Sulfonamides feature prominently in organic synthesis, materials science and medicinal chemistry, where they play important roles as bioisosteric replacements of carboxylic acids and other carbonyls. Yet, a general synthetic platform for the direct conversion of carboxylic acids to a range of functionalized sulfonamides has remained elusive. Herein, we present a visible light-induced, dual catalytic platform that for the first time allows for a one-step access to sulfonamides and sulfonyl azides directly from carboxylic acids. The broad scope of the direct decarboxylative amidosulfonation (DDAS) platform is enabled by the efficient direct conversion of carboxylic acids to sulfinic acids that is catalyzed by acridine photocatalysts and interfaced with copper-catalyzed sulfur–nitrogen bond-forming cross-couplings with both electrophilic and nucleophilic reagents.Sulfonamides are now accessible directly from carboxylic acids by a one-step, tricomponent decarboxylative amidosulfonation that provides the missing link between the two key functionalities. 相似文献
37.
The kinetics of precipitation reactions with110AgNO3 of some di (β-chlorethyl) amine derivates and hydrochlorides with esters of N-(p-aminobenzoyl)-L-aspartic acid as carriers in dimethylformamide-water mixture, were studied. The rate constants of these reactions were of the order of 10?4 1 · mol?1 · min?1. The concentrations of the corresponding hydrochloride solutions were measured by radiometric titration with110AgNO3 solution of given concentration. 相似文献
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Vuong LT Grow TD Ishaaya A Gaeta AL 't Hooft GW Eliel ER Fibich G 《Physical review letters》2006,96(13):133901
We theoretically and experimentally investigate the self-focusing of optical vortices in Kerr media. We observe collapse to a distinct self-similar profile, which becomes unstable to azimuthal perturbations. We analyze the azimuthal modulational instability for ring-shaped vortices and predict the number of azimuthal maxima solely as a function of power and topological charge. In our experiments, the observed multiple-filamentation patterns are in excellent agreement with our theoretical analysis. 相似文献