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71.
The preparation of 3-carboxymethylamino (or oxy or thio)-2-aryl (or arylmethyl)-isoindol-1-ones are described from hydroxylactams according to three different pathways. 相似文献
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Poly(trimethylene carbonate)/Poly(malic acid) Amphiphilic Diblock Copolymers as Biocompatible Nanoparticles 下载免费PDF全文
Ghislaine Barouti Ali Khalil Clement Orione Kathleen Jarnouen Dr. Sandrine Cammas‐Marion Dr. Pascal Loyer Prof. Sophie M. Guillaume 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(8):2819-2830
Amphiphilic polycarbonate–poly(hydroxyalkanoate) diblock copolymers, namely, poly(trimethylene carbonate) (PTMC)‐b‐poly(β‐malic acid) (PMLA), are reported for the first time. The synthetic strategy relies on commercially available catalysts and initiator. The controlled ring‐opening polymerization (ROP) of trimethylene carbonate (TMC) catalyzed by the organic guanidine base 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD), associated with iPrOH as an initiator, provided iPrO?PTMC?OH, which served as a macroinitiator in the controlled ROP of benzyl β‐malolactonate (MLABe) catalyzed by the neodymium triflate salt (Nd(OTf)3). The resulting hydrophobic iPrO?PTMC‐b‐PMLABe?OH copolymers were then hydrogenolyzed into the parent iPrO?PTMC‐b‐PMLA?OH copolymers. A range of well‐defined copolymers, featuring different sizes of segments (Mn,NMR up to 9300 g mol?1; ÐM=1.28–1.40), were thus isolated in gram quantities, as evidenced by NMR spectroscopy, size exclusion chromatography, thermogravimetric analysis, differential scanning calorimetry, and contact angle analyses. Subsequently, PTMC‐b‐PMLA copolymers with different hydrophilic weight fractions (11–75 %) self‐assembled in phosphate‐buffered saline upon nanoprecipitation into well‐defined nano‐objects with Dh=61–176 nm, a polydispersity index <0.25, and a negative surface charge, as characterized by dynamic light scattering and zeta‐potential analyses. In addition, these nanoparticles demonstrated no significant effect on cell viability at low concentrations, and a very low cytotoxicity at high concentrations only for PTMC‐b‐PMLA copolymers exhibiting hydrophilic fractions over 47 %, thus illustrating the potential of these copolymers as promising nanoparticles. 相似文献
75.
Influence of Equilibration Time in Solution on the Inclusion/Exclusion Topology Ratio of Host–Guest Complexes Probed by Ion Mobility and Collision‐Induced Dissociation 下载免费PDF全文
Glenn Carroy Charlotte Daxhelet Dr. Vincent Lemaur Dr. Julien De Winter Prof. Edwin De Pauw Prof. Jérôme Cornil Prof. Pascal Gerbaux 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(13):4528-4534
Host–guest complexes are formed by the creation of multiple noncovalent bonds between a large molecule (the host) and smaller molecule(s) or ion(s) (the guest(s)). Ion‐mobility separation coupled with mass spectrometry nowadays represents an ideal tool to assess whether the host–guest complexes, when transferred to the gas phase upon electrospray ionization, possess an exclusion or inclusion nature. Nevertheless, the influence of the solution conditions on the nature of the observed gas‐phase ions is often not considered. In the specific case of inclusion complexes, kinetic considerations must be taken into account beside thermodynamics; the guest ingression within the host cavity can be characterized by slow kinetics, which makes the complexation reaction kinetically driven on the timescale of the experiment. This is particularly the case for the cucurbituril family of macrocyclic host molecules. Herein, we selected para‐phenylenediamine and cucurbit[6]uril as a model system to demonstrate, by means of ion mobility and collision‐induced dissociation measurements, that the inclusion/exclusion topology ratio varies as a function of the equilibration time in solution prior to the electrospray process. 相似文献
76.
In this paper, we generalize earlier work dealing with maxima of discrete random variables. We show that row-wise stationary block maxima of a triangular array of integer valued random variables converge to a Gumbel extreme value distribution if row-wise variances grow sufficiently fast as the row-size increases. As a by-product, we derive analytical expressions of normalising constants for most classical unbounded discrete distributions. A brief simulation illustrates our theoretical result. Also, we highlight its usefulness in practice with a real risk assessment problem, namely the evaluation of extreme avalanche occurrence numbers in the French Alps. 相似文献
77.
Xiaoyan Zhang Pascal Tanner Alexandra Graff Cornelia G. Palivan Wolfgang Meier 《Journal of polymer science. Part A, Polymer chemistry》2012,50(12):2293-2318
Cell membranes are essential barriers in Nature. To understand their properties and functions and to develop desirable applications, a simple and elegant approach is to study membranes that mimic the cell membrane. Lipid bilayers represent simple models that are physiologically representative when in the form of mixtures of various lipids, but they are not adequately stable even when covered with amphipathic proteins or when combined with polymers, thus preventing technological applications. This makes necessary the design of completely synthetic membranes. In this respect, amphiphilic copolymers that self‐assemble under dilute aqueous conditions and generate supramolecular polymer vesicles or films are ideal candidates for synthetic membranes. Their versatility in terms of chemistry and properties (permeability, mechanical stability, thickness), if appropriately designed, enable the insertion of biological molecules, such as membrane proteins and biopores, or the attachment of biomolecules at their surfaces. Here, we present the domain of synthetic membranes based on amphiphilic copolymers beginning with their generation and up to their applications in medicine, the food industry, and technology. Even though significant progress has been made in combining them with membrane proteins, open questions remain with respect to desired properties that could accommodate biological molecules and support further development of the field, from both the point of view of fundamental understanding and of applications. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
78.
Julie Febvay Dr. Charles S. Demmer Dr. Pascal Retailleau Dr. Jeanne Crassous Dr. Laura Abella Prof. Jochen Autschbach Dr. Arnaud Voituriez Dr. Angela Marinetti 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(68):15609-15614
Phosphahelicenes with thiophosphinic acid and ester functions have been obtained by the oxidative photocyclisation of olefins bearing both a benzophenanthrene and a benzophosphole unit. When the method has been extended to olefins bearing a partially saturated benzophospholene unit, a divergent regioselectivity of the photocyclisation step has been observed, leading to new helicenes in which the phosphorus function is located on the external rim of the helical backbone. The observed regioselectivity correlates well with the free-valence numbers of the atoms involved in the photocyclisation reaction (DFT calculations). 相似文献
79.
A graph is -colorable if it admits a vertex partition into a graph with maximum degree at most and a graph with maximum degree at most . We show that every -free planar graph is -colorable. We also show that deciding whether a -free planar graph is -colorable is NP-complete. 相似文献
80.