- Synthesis of benzo[a]pyren-6-yl-substituted carboxylic acids
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The title compounds were synthesized from benzo[a]pyrene in three to four steps, depending on the chain length of the carboxylic acid. After iodination, alkanone chains were introduced by special Heck reactions. Transformation into carboxylic acids was achieved by haloform reaction and by Willgerodt-Kindler reaction. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Dyker, Gerald,Kadzimirsz, Daniel
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- UV-responsive degradable polymers derived from 1-(4-aminophenyl) ethane-1,2-diol
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A UV-responsive polymer was prepared via condensation polymerization of 2-nitrobenzyl(4-(1,2-dihydroxyethyl)phenyl)carbamate and azalaic acid dichloride. When the polymer was irradiated with UV light, the nitrobenzyl urethane protecting group was removed and the deprotected aniline underwent spontaneous 1,6-elimination reactions, resulting in degradation of the polymer. Nanoparticles with encapsulated Nile Red were formulated with the degradable polymer and triggered burst release of Nile Red was observed when the nanoparticles were irradiated by UV light.
- Ma, Liang,Baumgartner, Ryan,Zhang, Yanfeng,Song, Ziyuan,Cai, Kaimin,Cheng, Jianjun
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- Chromophore quench-Labeling: An approach to quantifying catalyst speciation as demonstrated for (EBI)ZrMe2/ b(C6F5)3?Catalyzed polymerization of 1?Hexene
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Chromophore-containing quench agents 2 and 3 enable quantitative active site counting and determination of the mass distribution of active catalyst polymeryls by refractive index (RI) and UV detected gel permeation chromatography (GPC) for the polymerization of 1-hexene catalyzed by (EBI)ZrMe2/B(C6F5)3. Time evolution of catalyst speciation data and the time profiles of monomer consumption, end-group generation, and bulk molecular weight distribution data have been analyzed by kinetic modeling to determine rate constants for initiation by insertion of hexene into a Zr?Me bond (ki), propagation (kp), chain transfer to form vinylidene (k1,2) and vinylene (k2,1) end groups, and reinitiation from a Zr?H bond (kr). Unlike previous models that assumed fast catalyst reinitiation, this analysis reveals that kr is considerably slower than kp; catalyst speciation data are critical to making this distinction. This study demonstrates that chromophore quench-labeling with 2 and 3 enables rapid, quantitative analysis of detailed kinetic models for catalytic olefin polymerization reactions using GPC with UV and RI detectors.
- Nelsen, D. Luke,Anding, Bernie J.,Sawicki, Julie L.,Christianson, Matthew D.,Arriola, Daniel J.,Landis, Clark R.
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p. 7398 - 7408
(2018/05/23)
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- Pyrene derived functionalized low molecular weight organic gelators and gels
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Pyrene derived binary functionalized low molecular weight organic gelators (FLMOGs) and gels thereof in selected organic solvents were synthesized and characterized. The functionality refers to a functional group that does not take part in formation of the supramolecular gel network, but remains free and available for other purposes, such as to bind nanoparticles or other molecules into the gel structure. Functional groups were observed to disturb gel formation strongly, if they interact with each other within the same supramolecule due to the formation of competitive structures. Preventing such interactions restored the original gel properties. A gel with weaker supramolecular bonding than the binding between the functional groups was successfully made by separating the functional groups by distance. The π-π-interaction was found to be of negligible significance to the supramolecular binding energy, but probably essential to align the molecules to a one-dimensional chain and bring them into the range of van der Waals forces mainly responsible for the binding in this system. Solvent was observed to increase the binding energy of the supramolecule. All molecules were characterized by spectroscopic techniques and elemental analysis. Selected gels were characterized with rheometry, scanning electron microscopy, UV- and fluorescence spectroscopy. Gelation kinetics and hysteresis were measured by UV-spectroscopy and a fast gelation process was observed for all the gelators studied. The melting enthalpies were measured by DSC and calculated theoretically by PM3 level of theory. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Hahma, Arno,Bhat, Shreedhar,Leivo, Kimmo,Linnanto, Juha,Lahtinen, Manu,Rissanen, Kari
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supporting information; body text
p. 1438 - 1448
(2009/02/04)
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- Compounds for determining the activity of phospholipase A2
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Compounds for determining the activity of phospholipase A2, are described herein, and include embodiments having formula (1) wherein L1 is derived from an ether (R1—OR2)m, wherein R1 and R2 are independently selected and are derived from a hydrocarbon having 1 to 12 carbon atoms, with m being an integer from 1 to 4, or from a hydrocarbon R having 1 to 20 carbon atoms; F is unsubstituted or substituted pyrene as a flouraphore; Q is a quencher, and L2 is C(O)-L1 or C(O)-L1-NH, wherein L1 is as defined above. These compounds may be used to determine the activity of phospholipase A2, in particular PAF-AH.
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- A convenient procedure for parallel ester hydrolysis
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The treatment of alkyl esters with barium hydroxide octahydrate in methanol followed by protonation with anhydrous hydrogen chloride affords carboxylic acids. The procedure does not require aqueous workup and is particularly suitable for parallel synthesis applications.
- Anderson, Marc O.,Moser, Jamie,Sherrill, John,Guy, R. Kiplin
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p. 2391 - 2393
(2007/10/03)
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