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1.
Abstract The synthesis and acid-catalyzed rearrangement of novel thiazolomorphinandienes have been presented. An isomerization was
observed simultaneously with the backbone transformation. An extensive study was performed to determine the major effects
of the isomerization of 2′-alkyl- and aryl-substituted thiazoloapocodeines into 3′-alkyl- and arylisothiazoloapocodeines.
The obtained results provided another practical example of the reversible benzisothiazole–benzothiazole-type isomerization
emphasizing the determining role of the thermal effects in the occurrence of these isomerization products. The obtained experimental
results and the proposed mechanism were in agreement with the calculated DFT data.
Graphical abstract
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Attila SiposEmail: |
2.
Attila Sipos Miklós Tóth Franziska K. U. Mueller Jochen Lehmann Sándor Berényi 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):473-478
Abstract The synthesis of 4H-thiochromene derivatives of apomorphines, a novel class of isoquinoline alkaloid-related compounds, has been achieved by
different O-dealkylation methods applied on previously published heteroring-fused aporphinoids. Detailed DFT study has been presented
regarding the mechanism of the L-selectride-mediated multiple O-dealkylation of a seven-ring aporphine analogue. Dopamine-binding tests confirmed the essential function of 11-hydroxy moiety
of the aporphine skeleton and revealed a remarkable D1 over D2 specificity for the derivative having the 4H-thiochromene ring system attached to positions 2 and 3 of the aporphine backbone.
Graphical Abstract
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Attila SiposEmail: |
3.
Edward B. Nikitin Sanjeev K. Dey David A. Lightner 《Monatshefte für Chemie / Chemical Monthly》2009,140(1):97-110
Abstract Six 10-nor-bilirubin analogs have been synthesized and investigated. Lacking the C(10) CH2 group, these linear tetrapyrroles have a bipyrrole core rather than a dipyrrylmethane core and thus a different shape. Whereas
the propionic acid groups of bilirubin are well engaged in intramolecular hydrogen bonding to the dipyrrinones, molecular
modeling studies of the 10-nor-rubins predict that propionic acid chains are too short to engage the CO2H hydrogen fully in intramolecular hydrogen bonding with the dipyrrinones. Butyric acid chains, however, can and do lead to
a stabilized conformation with a bipyrrole dihedral angle of approximately 115°. Spectroscopic studies verify the predictions
and vapor pressure osmometry indicates that the 10-nor-rubins with butyric acids are monomeric in CHCl3.
Graphical abstract
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David A. LightnerEmail: |
4.
Alexey Bobrovsky Valery Shibaev Vera Hamplova Miroslav Kaspar Milada Glogarova 《Monatshefte für Chemie / Chemical Monthly》2009,140(7):789-799
Abstract A novel chiral–photochromic side-chain polyacrylate with azobenzene fragments in the side groups has been synthesised. It
was shown that the polymer forms a smectic phase and a cholesteric supramolecular helical structure with selective light reflection
in IR spectral range. Thin spin-coated films of the polymer were prepared and their photooptical and chirooptical properties
were studied in detail. It was found that UV irradiation of the films led to E–Z isomerization of the azobenzene moieties with high conversion, which is dependent on thermal prehistory of the films. Subsequent
action of visible light results in partial recovery of the E-isomer content, whereas annealing leads to the full back conversion. Circular dichroism (CD) measurements revealed formation
of the helical supramolecular structure even in the initial spin-coated polymer films. The E–Z isomerization induces complete disruption of helical order in non-annealed films of the polymer, whereas in the smectic phase
of the annealed film only a significant decrease in CD values was found. In addition, the photoorientation phenomena induced
by polarized light were studied. It was shown that polarized light induces linear dichroism in the films provided by azobenzene
group orientation and the dichroism is stable at room temperature for a prolonged time. These combined chirooptical and photooptical
features of this novel polymer enable one to consider this multifunctional compound as a promising material for photonics
and for optical applications.
Graphical abstract
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Alexey BobrovskyEmail: |
5.
Edgar D. Goluch Bernhard Wolfrum Pradyumna S. Singh Marcel A. G. Zevenbergen Serge G. Lemay 《Analytical and bioanalytical chemistry》2009,394(2):447-456
Amperometric detection is ideally suited for integration into micro- and nanofluidic systems as it directly yields an electrical
signal and does not necessitate optical components. However, the range of systems to which it can be applied is constrained
by the limited sensitivity and specificity of the method. These limitations can be partially alleviated through the use of
redox cycling, in which multiple electrodes are employed to repeatedly reduce and oxidize analyte molecules and thereby amplify
the detected signal. We have developed an interdigitated electrode device that is encased in a nanofluidic channel to provide
a hundred-fold amplification of the amperometric signal from paracetamol. Due to the nanochannel design, the sensor is resistant
to interference from molecules undergoing irreversible redox reactions. We demonstrate this selectivity by detecting paracetamol
in the presence of excess ascorbic acid.
Figure
相似文献
Serge G. LemayEmail: |
6.
Influence of interface structure on mass transport in phase boundaries between different ionic materials 总被引:1,自引:0,他引:1
Carsten Korte N. Schichtel D. Hesse J. Janek 《Monatshefte für Chemie / Chemical Monthly》2009,140(9):1069-1080
Abstract Internal and external interfaces in solids exhibit completely different transport properties compared to the bulk. Transport
parallel to grain or phase boundaries is usually strongly enhanced. Transport perpendicular to an interface is usually blocked,
i.e., transport across an interface is often much slower. Due to the high density of interfaces in modern micro- and nanoscaled
devices, a severe influence on the total transport properties can be expected. In contrast to diffusion in metal grain boundaries,
transport phenomena in boundaries of ionic materials are still less understood. The specific transport properties along metal
grain boundaries are explained by structural factors like packing densities or dislocation densities in the interface region.
In most studies dealing with ionic materials, the interfacial transport properties are merely explained by the influence of
space charge regions. In this study the influence of the interface structure on the interfacial transport properties of ionic
materials is discussed in analogy to metallic materials. A qualitative model based on the density of misfit dislocations and
on interfacial strain is introduced for (untilted and untwisted) phase boundaries. For experimental verification, the interfacial
ionic conductivity of different multilayer systems consisting of stabilised ZrO2 and an insulating oxide is investigated as a funtion of structural mismatch. As predicted by the model, the interfacial conductivity
increases when the lattice mismatch is increased.
Graphical abstract
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Carsten KorteEmail: |
7.
8.
Anti-lysozyme aptamers are found to preferentially bind to the edge of a tightly packed lysozyme pattern. Such edge-binding
is due to the better accessibility and flexibility of the edge lysozyme molecules. Kelvin probe force microscopy (KPFM) was
used to study the aptamer–lysozyme binding. Our results show that KPFM is capable of detecting the aptamer–protein binding
down to the 30 nm scale. The surface potential of the aptamer–lysozyme complex is approximately 12 mV lower than that of the
lysozyme. The surface potential images of the aptamer-bound lysozyme patterns have the characteristic shoulder steps around
the pattern edge, which is much wider than that of a clean lysozyme pattern. These results demonstrate the potentials of KPFM
as a label-free method for the detection of protein–DNA interactions.
Figure Aptamers preferentially bind on the edge of a protein pattern as revealed by Kelvin force microscopy.
相似文献
Yuguang CaiEmail: |
9.
Seven columns with embedded polar functionality were evaluated for use in liquid chromatography with a focus on molecular
shape recognition. Tests based on Standard Reference Material 869b Column Selectivity Test Mixture for Liquid Chromatography
and the Tanaka test indicate that only two of the phases are slightly shape selective at 20 °C. The shape recognition characteristics
of the phases appear to be directly related to the density of the embedded polar ligands and the temperature of the separation,
consistent with trends observed with conventional hydrocarbon phases.
Catherine Rimmer is a Research Chemist at the National Institute of Standards and Technology where she began as a National Research Council Postdoctoral Fellow. Her research efforts are currently directed towards an improved understanding of chromatographic processes to advance the “state of the art” in chemical metrology. 相似文献
Catherine A. RimmerEmail: |
Catherine Rimmer is a Research Chemist at the National Institute of Standards and Technology where she began as a National Research Council Postdoctoral Fellow. Her research efforts are currently directed towards an improved understanding of chromatographic processes to advance the “state of the art” in chemical metrology. 相似文献
10.
Marco Rupprich Clemens Decristoforo Barbara Matuszczak 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):405-407
Abstract In contrast to the results presented in a previous report, the direct conversion of alcohols to alkyl fluorides with triphenylphosphine
and potassium fluoride in CCl4/DMF under mild conditions failed.
Graphical Abstract
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11.
Adel A.-H. Abdel-Rahman Ahmed E.-S. Abdel-Megied Hamed M. Abdel-Bary Abdel-Aleem H. Abdel-Aleem Emad M. I. Morcy Mohamed T. Shabaan 《Monatshefte für Chemie / Chemical Monthly》2009,140(5):559-564
Abstract A series of peptide derivatives conjugated with N1-protected tryptophan residue was synthesized. The prepared compounds were tested for antimicrobial activity against four
different bacterial species displaying different degrees of antibacterial activities or inhibitory actions.
Graphical Abstract
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12.
Raghunath B. Toche Bhausaheb K. Ghotekar Muddassar A. Kazi Madhukar N. Jachak 《Monatshefte für Chemie / Chemical Monthly》2009,140(2):235-241
Abstract A novel method for the synthesis of 3-(2-substituted ethyl)-2-methylbenzohetero[3,2-a]pyrimidines in high yield (80–85%) was achieved, which involves a dihydrofuranone intermediate, readily obtained from β-ketolactone
to 2-aminobenzoheterocycles. The major advantage of the methodology is the high yield and product purity.
Graphical Abstract
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13.
Abstract One-pot, three-components synthesis of 2,4,6-triarylpyridines and 5-unsubstituted-3,4-dihydropyrimidin-2(1H)-ones was performed under solvent-free conditions using molecular iodine as the catalyst in moderate to good product yields.
Graphical abstract
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14.
Gerard P. O’Sullivan Norma M. Scully Jean-Marie Prat Jeremy D. Glennon Benjamin Dietrich Volker Friebolin Klaus Albert 《Analytical and bioanalytical chemistry》2009,394(5):1261-1272
Supercritical carbon dioxide has attracted attention as a potential replacement for traditional organic solvents due to its
simplified workup procedures and reduced environmental impact—providing a green chemistry approach for organic solvent-free
functionalisation. In addition to the environmental benefits, the enhanced diffusivity observed in supercritical solvents
can often enhance reaction rates. We have applied these valuable features to the preparation of silica-bonded stationary phases
and examined their potential in liquid chromatography. We report the successful preparation and characterisation of polyether
silica based on Frechet dendrimers—this significantly enhances the range of stationary-phase chemistries that can be prepared
in supercritical fluids. First- and second-generation polyether silicas were prepared, characterised, end-capped and evaluated
for use as stationary phases for liquid chromatography.
Figure SRM1649 on 2nd generation polyether silica
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Jeremy D. GlennonEmail: |
15.
Emanuel Makrlík Ji?í Dybal Petr Vaňura 《Monatshefte für Chemie / Chemical Monthly》2009,286(1):1289-1292
Abstract From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constant
of protonated tetraethyl p-tert-butylcalix[4]arene tetraacetate in nitrobenzene saturated with water was determined. By using DFT calculations, the most
probable structure of the tetraethyl p-tert-butylcalix[4]arene tetraacetate·H3O+ complex species was derived.
Graphical Abstract
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16.
Emanuel Makrlík Jiří Dybal Petr Vaňura 《Monatshefte für Chemie / Chemical Monthly》2009,140(3):251-254
Abstract From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constant
of the valinomycin–lithium complex in nitrobenzene saturated with water was determined. Further, the structure of the resulting
complex was indicated by means of the density functional level of theory (DFT) calculations.
Graphical abstract
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17.
Barahman Movassagh Mohammad Soleiman-Beigi 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):409-411
Abstract A simple, highly efficient, and green protocol has been developed for preparation of sulfides from alkyl or aryl thiols and
benzyl-, allyl-, t-butyl, and adamantyl halides under solvent- and catalyst-free conditions.
Graphical abstract
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18.
Issa Yavari Rahimeh Hajinasiri S. Zahra Sayyed-Alangi 《Monatshefte für Chemie / Chemical Monthly》2009,140(2):205-207
Abstract 1-Ethyl-3-methylimidazolium bromide was used as a green recyclable alternative to volatile organic solvents for KOH catalyzed
three-component synthesis of diethyl alkylsulfanylmethylmalonates from aldehydes, diethyl malonate, and alkylthiols.
Graphical Abstract A synthesis of diethyl alkylsulfanylmethylmalonates catalyzed by KOH in an ionic liquid
相似文献
19.
Ch. Sree Lakshmi H. Rehaman Adari Bhaskar Rao 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):611-613
Abstract The enzymatic cyclization of phenoxyacetylcyanomethylenetriphenylphosphorane derivatives using pre-treated baker’s yeast cells,
a rapid one-pot assembly of heteromacrocyclic compounds, is described.
Graphical abstract
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20.
Robabeh Baharfar Seyed M. Vahdat Fatemeh G. Hakimabadi 《Monatshefte für Chemie / Chemical Monthly》2009,140(5):489-493
Abstract An efficient one-pot reaction of dialkyl acetylenedicarboxylates with 2,4-dihydroxybenzo(or aceto)phenones in the presence
of triphenylphosphine produces 5-hydroxy- and 7-hydroxycoumarin derivatives. The novel procedure features short reaction time,
fairly good yields, and simple workup.
Graphical abstract
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