bluuebunny/crossref_metadata_2025 huggingface dataset:
Expansion of Vα24+Vβ11+ NKT cells from cord blood mononuclear cells using IL‐15, IL‐7 and Flt3‐L depends on monocytes
Authors: Okada Hikaru , Nagamura‐Inoue Tokiko , Mori Yuka , Takahashi Tsuneo A.
Published: December 2005

Human Vα24+Vβ11+ NKT cells are a unique T cell population specifically and potently activated by α‐galactosylceramide (αGalCer; KRN7000) presented by CD1d. Here, we present a simple and efficient method for expanding Vα24+Vβ11+ NKT cells from human cord blood mononuclear cells (CBMNC) using αGalCer in the presence of interleukin (IL)‐15, IL‐7 and Flt3‐L. The addition of αGalCer from day 0, compared to its addition from day 8 or day 15, induced a greater expansion of NKT cells. The maximal expansion of NKT cells was observed after 15 days (2300‐fold). Thereafter, the number of NKT cells decreased slowly, a decrease that was correlated with the diminution of CD1d‐positive cells. NKT cell proliferation induced by αGalCer was not observed when CD1d‐expressing monocytes were depleted from CBMNC, whereas B cell and dendritic cell depletions had no effect. Expanded NKT cells were CD4+CD8– and secreted both IL‐4 and IFN‐γ. In this system, CD3+ T cells and CD3–CD56+ NK cells were also expanded. However, the expansion of NKT cells had no significant functional effect on T and NK cells. This expansion method of CBMNC‐derived NKT cells is simple and may be helpful for clinical use.
Direct manipulation of activator protein‐1 controls thymocyte proliferation in vitro
Authors: Thornton Tina M. , Zullo Alfred J. , Williams Kristi L. , Taparowsky Elizabeth J.
Published: December 2005

B cell activating transcription factor (BATF) belongs to the activator protein‐1 (AP‐1) superfamily of basic leucine zipper transcription factors and forms heterodimers with Jun that possess minimal transcriptional activity. Mice carrying a p56lckHA‐BATF transgene were created to observe the effects of constitutive expression of this well‐characterized AP‐1 inhibitor on T cell proliferation. Consistent with the role of AP‐1 in promoting the proliferation of many cell types, BATF‐transgenic thymocytes proliferate poorly in vitro when stimulated with anti‐CD3ϵ and anti‐CD28 antibodies or with Concanavalin A. However, when BATF‐transgenic thymocytes were stimulated using a standard treatment of PMA and ionomycin, proliferation is normal. The responsiveness to PMA and ionomycin can be attributed to the dramatic disappearance of the hemagglutinin antigen (HA)‐tagged BATF protein which is a PKC‐dependent process caused by the down‐regulation of the p56lck proximal promoter coupled with the rapid turnover of the HA‐BATF protein. These studies describe conditions of T cell stimulation that negatively influence transcription of the widely used p56lck proximal promoter expression cassette. In addition, the unique circumstances of this regulation were exploited to demonstrate that inhibition of AP‐1 activity by BATF exerts a direct, and reversible, effect on T cell proliferation in vitro.
Leukocyte‐associated Ig‐like receptor‐1 has SH2 domain‐containing phosphatase‐independent function and recruits C‐terminal Src kinase
Authors: Verbrugge Annelies , Rijkers Eva S. K. , Ruiter Talitha de , Meyaard Linde
Published: December 2005

Most inhibitory receptors in the immune system contain one or several immunoreceptor tyrosine‐based inhibitory motifs (ITIM) and recruit the SH2 domain‐containing phosphatases SHP‐1, SHP‐2 and/or SHIP, which are generally believed to be essential for the inhibitory function. However, it has not been systematically investigated whether ITIM‐bearing receptors exert their function through alternative interactions. Here we describe that leukocyte‐associated Ig‐like receptor (LAIR)‐1 has inhibitory function in DT40 chicken B cells that lack both SHP‐1 and SHP‐2. In addition, we found that LAIR‐1 did not recruit SHIP upon phosphorylation. Thus, LAIR‐1 can function independently from SH2 domain‐containing phosphatases and must recruit at least one other signaling molecule. Using a yeast‐tri‐hybrid system, we found that phosphorylated LAIR‐1 bound the C‐terminal Src kinase (Csk). The interaction required the SH2 domain of Csk and phosphorylation of the tyrosine in the N‐terminal ITIM of LAIR‐1. We propose that Csk is an additional player in the regulation of the immune system by ITIM‐bearing receptors.
Synthesis of Novel S‐Bridged Heterotrinuclear Complexes Containing Six‐Membered Chelate Rings: Structural, Spectroscopic, and Electrochemical Properties of [Co{Rh(apt)3}2]3+ (apt = 3‐Aminopropanethiolate)
Authors: Amir Nagina , Motonishi Masaru , Fujita Mitsuharu , Miyashita Yoshitaro , Fujisawa Kiyoshi , Okamoto Ken‐ichi
Published: January 2006

A bidentate ligand, 3‐aminopropanethiolate (apt), was synthesized and treated with RhCl3·3H2O in basic water to yield a novel mononuclear complex, fac(S)‐[Rh(apt)3] (1), which was characterized by spectroscopic methods. Furthermore, the reaction of 1 with CoCl2·6H2O in water formed the linear‐type, S‐bridged trinuclear complexes ΔΛ‐[Co{Rh(apt)3}2]3+ (2a) and ΔΔ/ΛΛ‐[Co{Rh(apt)3}2]3+ (2b), which were characterized by stereochemical, spectrochemical, and electrochemical methods. 2a and 2b are stable and exhibit trivalency in water. X‐ray crystallographic analysis of 2a and 2b showed that all of the bridging sulfur atoms are fixed in the R configuration for the Δ unit and in the S configuration for the Λ unit, and each complex has six six‐membered chelate rings, all of which are in the chair conformation. The crystal structure of the corresponding 2‐aminoethanethiolate (aet) trinuclear complex ΔΛ‐[Co{Rh(aet)3}2]3+ (4a) was also determined. The structures of 2a and 2b have some differences from that of 4a as a result of the six‐membered chelate rings. The Co···Rh distances in 2a and 2b [3.0490(4) and 3.063(1) Å] are significantly longer than this distance in the aet complex 4a [2.9139(2) Å]. The UV/Vis absorption spectra of 2a and 2b indicate a shift to higher energies as compared with 4a and ΔΔ/ΛΛ‐[Co{Rh(aet)3}2]3+ (4b). The chemical shifts for the NCH2 and SCH2 carbon atoms in 2a and 2b are shifted to higher fields than those for 4a and 4b in the NMR spectra. The CoIII/II redox potential values are –0.56 V (2a) and–0.57 V (2b) compared with –0.35 V (4a) and –0.36 V (4b). This shows that the CoIII state is more stable in 2a and 2b than it is in 4a and 4b. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis of Chalcogeno[3‐(pyrid‐2‐yl)‐1‐azaallyl]germanium Complexes
Authors: Leung Wing‐Por , Chong Kim‐Hung , Wu Yuen‐Sze , So Cheuk‐Wai , Chan Hoi‐Shan , Mak Thomas C. W.
Published: December 2005

The reaction of [Ge{C(C5H4N‐2)C(Ph)N(SiMe3)2}{N(SiMe3)C(Ph)C(SiMe3)(C5H4N‐2)}] (1) and [Ge{N(SiMe3)C(Ph)C(SiMe3)(C5H4N‐2)}Cl] (2) with stoichiometric amounts of elemental chalcogens in toluene affords [Ge(E){C(C5H4N‐2)C(Ph)N(SiMe3)2}{N(SiMe3)C(Ph)C(SiMe3)(C5H4N‐2)}] [E = S (3), Se (4)] and [Ge(E){N(SiMe3)C(Ph)C(SiMe3)(C5H4N‐2)}Cl] [E = S (5), Se (6)], respectively. Compounds 3–6 were characterized by X‐ray analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and X‐ray Crystal Structures of the New, Three‐Dimensional Ethylenediphosphonates [A{HO3P(CH2)2PO3H2}] (A = Alkali Metal, Tl, or NH4): Solid Brönsted Acids That Exhibit Topotactic Intercalation and Deintercalation of Ammonia
Authors: Rao Koya Prabhakara , Vidyasagar Kanamaluru
Published: December 2005

Seven new ethylenediphosphonates with the formula [A{HO3P(CH2)2PO3H2}] [A = Li (1), Na (2), K (3), Rb (4), Cs (5), Tl (6), and NH4 (7)], have been synthesized and characterized by single‐crystal X‐ray diffraction, infrared spectroscopy, and thermal studies. They have four types of three‐dimensional structures, with variations in the coordination of the A+ ions. All of them are solid Brönsted acids that undergo room‐temperature, acid–base intercalation reactions with ammonia. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Hydrothermal Synthesis and Structural Characterization of Two pH‐Controlled Cd–Squarate Coordination Frameworks, [Cd2(C4O4)2.5(H2O)4]·(dpaH)·1.5(H2O) and [Cd(C4O4)(dpa)(OH2)] (dpa = 2,2′‐dipyridylamine)
Authors: Wang Chih‐Chieh , Yang Cheng‐Han , Lee Gene‐Hsiang
Published: December 2005

Two extended coordination frameworks of CdII–squarate complexes with the formulas [Cd2(C4O4)2.5(H2O)4](dpaH)·1.5(H2O) (1) and [Cd(C4O4)(dpa)(H2O)] (2) (dpa = 2,2′‐dipyridylamine) have been synthesized under hydrothermal conditions and characterized by single‐crystal X‐ray diffraction studies. Structural determination reveals that compound 1 consists of a free monoprotonated 2,2′‐dipyridylamine ion (dpaH+) and a two‐dimensional (2D) anionic, layered framework, {[Cd2(C4O4)2.5(H2O)4]–}, which is formed with two antiprismatic square‐boxes as the fundamental building unit through the connection between CdII ions and hybrid μ1,2,3‐, μ1,2,3,4‐squarates. Each square‐box acts as a host for the inclusion of one pyridine ring of dpaH+. Adjacent dpaH+ cations are then self‐assembled by the parallel alignment of the other pyridine ring of dpaH+ to complete a 3D network with one‐dimensional (1D) channels intercalated by water molecules. Compound 2 contains a distorted octahedral CdII center coordinated by two squarates, two waters and one dpa ligand to form a 1D 2‐legged, ladder‐like framework by the connection of a [Cd(dpa)(μ2‐H2O)]24+ dimeric unit and a μ1,2‐squarate. Weak π–π stacking interaction and hydrogen bonds of N–H···O, O–H···O and C–H···O among the squarate, water and dpa ligands provide additional intra‐ and intermolecular interactions on the stabilization of these two polymeric frameworks. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Structural Diversity of Host–Guest and Intercalation Complexesof Fullerene C60
Authors: Makha Mohamed , Purich Ariaan , Raston Colin L. , Sobolev Alexandre N.
Published: December 2005

Pristine fullerene C60 has a fcc structure. Crystallisation of the fullerene in a variety of solvents can lead to inclusion complexes, as well as discrete host–guest complexes in the presence of cavitands and porphyrins, and related molecules. The complexes retain varying degrees of fullerene···fullerene interactions at the van der Waals limit, except in a limited number of cases where the fullerenes are completely shrouded by one or more included/host molecule. Analysis of the fullerene···fullerene interactions in these complexes reveals a diverse structural arrangement of the fullerenes. They can be organised into dimers, single linear columns or zigzag chains, double columns, spectacular fivefold Z‐shaped columnar arrays, hexagonal close‐packed layers, corrugated sheets, honeycomb motifs, non‐close‐packed layers and complex three‐dimensional networks. Disorder of the fullerenes in the solid state is common, although structures with close‐packed planar arrangements of C60 molecules and/or with symmetry matching between the host molecule and the fullerene (two‐, three‐ and fivefold symmetry) tend to have less disorder of the fullerene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Bundle of Nanobelts Up to 4 cm in Length: One‐Step Synthesis and Preparation of Titanium Trisulfide (TiS3) Nanomaterials
Authors: Ma Jingjing , Liu Xiaoyang , Cao Xuejing , Feng Shouhua , Fleet Michael E.
Published: December 2005

One‐dimensional (1D) titanium trisulfide (TiS3) nanobelt bundles up to 4 cm in length have been successfully synthesized through an easy and common chemical vapor transition (CVT) process. The as‐synthesized samples were characterized by X‐ray powder diffraction (XRD), polarized light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). All microscopic observations indicated a belt‐like morphology. Powder XRD patterns showed that TiS3 crystallized in the monoclinic system with a = 4.958(1) Å, b = 3.393(1) Å, c = 8.793(3) Å and β = 97.27(5)°. TEM images revealed a nanostructure with an interplanar spacing of 0.87 nm. The ED pattern and HRTEM images confirmed the [014] elongated direction and the [001] dilated direction of the bundle of TiS3 nanobelts. Its tensile strength (TS) was further examined with a universal testing machine with 20 N as the biggest strength: the maximum stress and the break strain were 111.027 MPa and 97.1 %, respectively. Because the TiS3 nanocrystals are up to 4 cm in length and flexible enough to be cut into small pieces, they should be used directly in electrical and electronic applications. Also, these nanomaterials are synthesized and prepared by a simple one‐step process. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Single‐Electron‐Transfer Reactions of α‐Diimine dpp‐BIAN and Its Magnesium Complex (dpp‐BIAN)2–Mg2+(THF)3
Authors: Fedushkin Igor L. , Makarov Valentine M. , Rosenthal Esther C. E. , Fukin Georgii K.
Published: December 2005

The reactions of (dpp‐BIAN)Mg(THF)3 (1) {dpp‐BIAN = 1,2‐bis[(2,6‐diisopropylphenyl)imino]acenaphthene} with ethyl halides EtX (X = Cl, Br, I) in hexane proceed by single‐electron transfer (SET) from the metal complex to the organic halide. Complexes [(dpp‐BIAN)(Et)]MgX(THF)n [X = Cl, n = 0 (2); X = Br, n = 2 (3); X = I, n = 1 (4)] are the products of ethyl transfer to an imine carbon atom of a coordinated diimine ligand. The compound [(dpp‐BIAN)(Et)]MgBr (3a) was obtained from the reaction of free dpp‐BIAN with ethylmagnesiumbromide in hexane. In this case SET from the Grignard reagent to the neutral diimine takes place. Compounds 2–4 and 3a were isolated as crystals and characterized by 1H NMR spectroscopy. The molecular structure of 3 was determined by single‐crystal X‐ray analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Self‐Assembly, Structure and Solution Dynamics of Tetranuclear Zn2+ Hydrazone [2×2] Grid‐Type Complexes
Authors: Barboiu Mihail , Ruben Mario , Blasen Georges , Kyritsakas Nathalie , Chacko Elizabeth , Dutta Manisha , Radekovich Olga , Lenton Kimberly , Brook David J. R. , Lehn Jean‐Marie
Published: December 2005

We describe the self‐assembly processes as well as the structural and physico‐chemical properties of [2×2]Zn2+4 grid complexes involving the bis‐tridentate ligands 7–12, based on bis(hydrazone)pyrimidine complexation subunits and octahedrally coordinated Zn2+ ions. The NMR spectroscopic data and the X‐ray crystal structure results indicate that in solution and in the solid state the complexes 13–18 adopt a very compact arrangement providing stable [2×2] hydrazone‐grid arrays. The π–π stacking between the phenyl ring and the hydrazone units of the perpendicular ligands in the complexes induces a perfect orthogonal arrangement suitable for applications in self‐organized metallosupramolecular systems. Zinc complexes provide an opportunity to study the acid–base chemistry without the added effects due to paramagnetism or redox chemistry. The intermediate protonated grids undergo relatively rapid proton exchange on the NMR timescale, the presence of a sharp pyrimidine proton resonance suggesting that there is significant delocalization of the negative charge along the backbone of the ligand. Rotation of the phenyl ring is observed. It involves probably a mechanism in which one of the ligands partially dissociates allowing the initially intercalated phenyl group to rotate, before recoordination of the terminal pyridine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
On the Conformation of 8‐Membered Ring Heterocycles – Dynamic and Static Conformational Analysis of Acylated Hexahydrobenzazocines
Authors: Hassner Alfred , Amit Boaz , Marks Vered , Gottlieb Hugo E.
Published: December 2005

A high‐field NMR analysis of several acylated hexahydrobenzazocines indicates that, surprisingly, ring methylene groups are typically diastereotopic at room temperature, as the barriers for the process of enantiomerization of the eight‐membered ring are much higher than expected. It is shown that ring inversion is correlated (but not concerted) with rotation of the amide moiety, as the carbonyl is forced out of conjugation with the nitrogen in the transition state. A detailed analysis of vicinal proton‐proton coupling constants, supported by molecular mechanics calculations, indicates that these compounds exist at room temperature as a mixture of fast‐interconverting conformers of the octacycle. This is proved by the observation of two species in the 13C NMR spectrum of the parent compound, at temperatures below–90 °C. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Preparation and Electrochemical Properties of 1,4,8,11,15,18,22,25‐Octalkylphthalocyanines Containing Four Trithiole Rings
Authors: Kimura Takeshi , Suzuki Takahiro , Takaguchi Yutaka , Yomogita Akinori , Wakahara Takatsugu , Akasaka Takeshi
Published: December 2005

1,4,8,11,15,18,22,25‐Octalkyl‐2,3;9,10;16,17;23,24‐tetrakis(o‐xylylenedithio)phthalocyanines 4a–d (alkyl = ethyl, butyl, octyl, and dodecyl) were prepared in moderate yields by treatment of 3,6‐dialkyl‐4,5‐(o‐xylylenedithio)phthalonitriles 3a–d with lithium in n‐pentanol. Reductive removal of the four o‐xylylene groups from 4b and 4c was performed with lithium/THF/ammonia, and the octathiolate anions generated were then treated with elemental sulfur to give the new phthalocyanines 6b and 6c, respectively, each containing four trithiole rings, after partial desulfurization and ring‐contraction reactions of the corresponding phthalocyanines 5b and 5c. The structures of the phthalocyanines were determined by 1H NMR spectroscopy and MALDI‐TOF mass spectrometry. The absorptions of the Q‐bands of 4a–d were observed at λmax ≈ 770 nm in their UV/Vis spectra, while those of 4b‐Ni, 5b, 5c, and 6c were found in a region, blue‐shifted relative to 4a–d. When the UV/Vis spectrum of 6c wasmeasured in concentrated sulfuric acid, the λmax value of its Q‐band was 887 nm (log ϵ = 4.5), which suggests that the positive charge generated on 6c strongly affects the π‐conjugation of the phthalocyanine skeleton. The ESR spectrum was observed as one broadening signal on treatment of 6c with SbCl5. The redox potentials of the phthalocyanines were determined by cyclic voltammetry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
β‐Arylthio‐α‐chloroalkyl Ethers — Novel 1,1‐Bis‐electrophiles for Geminal Alkylation
Authors: Gromov Alexey V. , Smit William A.
Published: December 2005

A novel protocol for geminal alkylation is suggested based upon the consecutive generation of two cationoid intermediates from the easily prepared adducts of arylsulfenyl chlorides and vinyl ethers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A New Three‐Component Cascade Reaction to Yield 3‐Spirocyclopropanatedβ‐Lactams
Authors: Zanobini Alessandra , Brandi Alberto , de Meijere Armin
Published: December 2005

A one‐pot three‐component reaction for the direct conversion of certain alkylhydroxylamine hydrochlorides 8 (alkyl = benzyl, p‐methoxybenzyl, benzhydryl, tert‐butyl), formaldehyde (9) or an alkyl glyoxylate (10) and bicyclopropylidene (2) to furnish 3‐spirocyclopropanated 2‐azetidinones 7, 11 has been developed. Microwave heating of mixtures of the three components in the presence of sodium acetate in ethanol for 15–120 min furnished the products 7, 11 in 49–78 % yield (7 examples). A new protocol for the oxidative deprotection of the 3‐spirocyclopropanated methyl 1‐(p‐methoxybenzyl)‐2‐carboxylate 11b‐Me provides the β‐lactam building block 17‐Me in 90 % yield, and the latter can be reprotected and activated with an N‐tert‐butoxycarbonyl (Boc) group in 82 % yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Estimation of Joule heating effect on temperature and pressure distribution in electrokinetic‐driven microchannel flows
Authors: Chein Reiyu , Yang Yeong Chin , Lin Yushan
Published: December 2005

In this study we present simple analytical models that predict the temperature and pressure variations in electrokinetic‐driven microchannel flow under the Joule heating effect. For temperature prediction, a simple model shows that the temperature is related to the Joule heating parameter, autothermal Joule heating parameter, external cooling parameter, Peclet number, and the channel length to channel hydraulic diameter ratio. The simple model overpredicted the thermally developed temperature compared with the full numerical simulation, but in good agreement with the experimental measurements. The factors that affect the external cooling parameters, such as the heat transfer coefficient, channel configuration, and channel material are also examined based on this simple model. Based on the mass conservation, a simple model is developed that predicts the pressure variations, including the temperature effect. An adverse pressure gradient is required to satisfy the mass conservation requirement. The temperature effect on the pressure gradient is via the temperature‐dependent fluid viscosity and electroosmotic velocity.
Calibration of migration times of variable salinity samples with internal standards in capillary electrophoresis
Authors: Riaz Asif , Chung Doo Soo
Published: December 2005

A practical approach is presented for identifying the analyte peaks stacked by transient ITP (TITP) in samples of uncontrolled salinity. For TITP with chloride ions acting as the leading electrolyte, the effect of matrix chloride of an unknown concentration was calibrated using multiple internal standards to predict the migration times of weakly acidic anionic analytes behaving as strong electrolytes to an accuracy of over 99.9%. The calibration equations for the migration time of an analyte are given as a function of the migration times of internal standards using the mobilities of the relevant ions as parameters. The effects of matrix chloride and various separation conditions such as the temperature, plug length, ionic strength, and pH of the BGE were completely eliminated from the calibration equations. In addition, the actual mobilities, determined for a standard saline sample under the working conditions, were used, and thus, there was no need to conduct supplementary experiments to determine the absolute mobilities at infinite dilution. The internal standards were dyes, which were easily identified in an auxiliary channel monitoring the absorbance at a longer wavelength. For five standard saline matrices containing 100–300 mM NaCl at intervals of 50 mM, the mean absolute error (MAE) in migration times calibrated with two internal standards was 0.4 s (n = 5×13). For an electropherogram of a real standard reference urine sample, peaks of spiked analytes were identified with an MAE of 0.9 s (n = 13) without conductivity normalizing or desalting of the sample.
Loading capacity of carrier ampholytes – based buffers in capillary electrophoresis
Authors: Busnel Jean‐Marc , Descroix Stéphanie , Godfrin Dominique , Hennion Marie‐Claire , Peltre Gabriel
Published: December 2005

Narrow pH cuts of carrier ampholytes (CAs), originally designed for IEF, have been used as BGEs in CE. Their physicochemical properties, rather high buffering capacity and low conductivity, allow very efficient protein separations under high electric field strength. Due to their isoelectric properties, CA BGEs are expected to present a low ionic concentration and consequently a low loading capacity. In this study, we developed a simple method that allows the estimation of the loading capacity of a UV‐absorbing BGE by CE. We first characterized in terms of loading capacity, classical ammediol‐chromate UV‐absorbing BGEs and a 10 mM histidine solution, a classical isoelectric buffer. Then, the loading capacity of four different CA‐based BGEs has been assessed. Experimental results have shown that the CA‐based buffers were presenting a rather high loading capacity, comparable to classical buffer ones and far higher than the one of the 10 mM histidine solution.
The unified equation for the evaluation of first order reactions in dynamic electrophoresis
Authors: Trapp Oliver
Published: December 2005

The unified equation was validated for first order reactions in dynamic CE with a data set of 31 250 elution profiles. Comparison with the results from conventional iterative computer simulation revealed that the unified equation is superior in terms of success rate and precision. The unified equation was applied to determine the cis‐trans isomerization rate constants of the angiotensin converting enzyme inhibitor captopril. The separation of the rotational cis‐trans isomeric drug has been performed in an aqueous 66 mM citric acid/Tris buffer at pH 3.0 in a 50 cm polyacrylamide‐coated fused‐silica capillary. Interconversion profiles featuring pronounced plateau formation and peak broadening were observed. Activation parameters ΔH≠ and ΔS≠ were obtained from temperature‐dependent measurements between 10 and 25°C in 2.5 K steps. From the activation parameters the isomerization barriers of captopril at 37°C under acidic conditions were calculated to be ΔG≠trans→cis = 90.6 kJ/mol and ΔG≠cis→trans = 84.6 kJ/mol. By comparison of the kinetic data with the results obtained under basic conditions (pH 9.3) a mechanism of isomerization could be proposed.
Internal Nucleophilic Termination in Acid‐Mediated Polyene Cyclizations Part 4
Authors: Snowden Roger L. , Linder Simon
Published: December 2005

Treatment of the unsaturated bicyclic homoallylic alcohols (E)‐ and (Z)‐5 and (Z)‐ and (E)‐10 and allenic alcohol 16 with an excess of ClSO3H in 2‐nitropropane or CH2Cl2 at − 80° afforded, in moderate yields (ca. 30–70%), diastereoisomer mixtures of racemic tetracyclic ethers 12a–c (Table 1) and 17a,b (Table 2), respectively. These kinetically controlled stereospecific transformations are believed to proceed via concerted or nonconcerted pathways (see Schemes 4 and 6) and the results are fully consistent with our earlier work. Representing novel didehydro bridged analogues of known, olfactively active labdane tricyclic ethers, the organoleptic properties of 12a–c and 17a,b are briefly described, especially those of 12c which, in the context of structure–activity studies, is a racemic didehydro analogue of the known ambergris odorant Ambrox®.
Synthesis of cis‐Hedione® and Methyl Jasmonate via Cascade Baylis–Hillman Reaction and Claisen Ortho Ester Rearrangement
Authors: Chapuis Christian , Büchi George H. , Wüest Hans
Published: December 2005

The exocyclically unsaturated conjugated keto esters 10, obtained via a Claisen ortho ester rearrangement of the allylic hydroxy ketones 9, were either directly hydrogenated or partially isomerized into the endocyclically unsaturated tetrasubstituted didehydrojasmonoid intermediates 14, prior to a more selective hydrogenation with Pd/C in cyclohexane to the disubstituted oxocyclopentaneacetates 15 (Scheme 2). The key intermediates 9 were obtained either by a four‐step sequence, including acetal protection/deprotection from enone 1, in the specific case of hydroxy ketone 9a (Scheme 1), or more directly and generally by a Baylis–Hillman reaction from cyclopent‐2‐en‐1‐one (16) and the appropriate aldehydes 17 (Scheme 2). The judicious choice of these aldehydes opens versatile modifications for the stereoselective introduction of the partially cis‐ or epimerized trans‐C(2) jasmonoid side chain, while the Baylis–Hillman reaction, catalyzed by chiral [1,1′‐binaphthalene]‐2,2′‐diols (BINOLs) 19 (Scheme 3), may be efficiently conducted in a one‐pot cascade fashion including the ortho ester Claisen rearrangement.
Amphiphilic Polymethacrylate‐ and Polystyrene‐Based Chemical Delivery Systems for Damascones
Authors: Berthier Damien , Trachsel Alain , Fehr Charles , Ouali Lahoussine , Herrmann Andreas
Published: December 2005

Amphiphilic polystyrene‐ and polymethacrylate‐based β‐acyloxy ketones were investigated as potential delivery systems for the controlled release of damascones by retro‐1,4‐addition in applications of functional perfumery. A series of random copolymers being composed of the hydrophobic damascone‐release unit and a second hydrophilic monomer were obtained by radical polymerization in organic solution by using 2,2′‐azobis[2‐methylpropanenitrile] (AIBN) as the radical source (Schemes 2 and 3). A first evaluation of the polymer conjugates in acidic or alkaline buffered aqueous solution, and in the presence of a surfactant, showed that polymethacrylates and polystyrenes having a carboxylic acid function as hydrophilic group are particularly interesting for the targeted applications (Table 2). The release of δ‐damascone (1) from polymers with poly(methacrylic acid) and poly(vinylbenzoic acid) comonomers in different stoichiometric ratios was thus followed over several days at pH 4, 7, and 9 by comparison of fluorescence probing, solvent extraction, and particle‐size measurements (Tables 3 and 4). In acidic media, the polymers were found to be stable, and almost no δ‐damascone (1) was released. In neutral or alkaline solution, where the carboxylic acid functions are deprotonated, the concentration of 1 increased over time. In the case of the polymethacrylates, the fluorescence probing experiments showed an increasing hydrophilicity of the polymer backbone with increasing fragrance release, whereas in the case of the polystyrene support, the hydrophilicity of the environment remained constant. These results suggest that the nature of the polymer backbone may have a stronger influence on the fragrance release than the ratio of hydrophilic and hydrophobic monomers in the polymer chain.
Synthesis and Optical Resolution of the Floral Odorant (±)‐2,3‐Dihydro‐2,5‐dimethyl‐1H‐indene‐2‐methanol, and Preparation of Analogues
Authors: Vial Christian , Bernardinelli Gérald , Schneider Philippe , Aizenberg Michael , Winter Béat
Published: December 2005

The title compound (±)‐1, a recently discovered, valuable, floral‐type odorant, has been synthesized by a straightforward procedure (Scheme 1). To determine the properties of the enantiomers of 1, their separation by preparative HPLC and the determination of their absolute configuration by X‐ray crystallography were carried out (Figure). Furthermore, the analogues 2–6 were synthesized, either from differently methylated 2‐methylindan‐1‐ones (Schemes 2 and 3) or, in the case of the 2,4,6‐trimethylated homologue 6, by a completely different synthetic approach (Scheme 4). An evaluation of (+)‐(S)‐1, (−)‐(R)‐1, and (±)‐1 showed only minor differences in terms of odor (Table).
Synthesis and Odor Properties of Substituted Indane‐2‐carboxaldehydes. Discovery of a New Floral (Muguet) Fragrance Alcohol
Authors: Winter Béat , Gallo‐Flückiger Sandrine
Published: December 2005

Eight substituted indane‐2‐carboxaldehydes (= 2,3‐dihydro‐1H‐indene‐2‐carboxaldehydes), related to conformationally constrained analogues of floral‐type odorants, were synthesized in order to examine the effect of modifying the lipophilic part of the odorants (Schemes 1 and 2). None of the modified compounds showed better olfactive properties than the original ones (Tables 1 and 2), but an intermediate alcohol, 29, revealed itself as a valuable new member in the family of floral muguet (lily‐of‐the‐valley)‐type odorants.
Aldols by Michael Addition: Application of the retro‐Michael Addition to the Slow Release of Enones
Authors: Fehr Charles , Galindo José
Published: December 2005

The reversibility of Michael additions was exploited to create Michael adduct profragrances of several enones. Some of them proved to exhibit interesting properties. The synthesis of aldols (3‐hydroxy ketones) by Michael addition also opens a ready access to 1,3‐diketones.
Intercalating Nucleic Acids with Insertion of 5‐[(Pyren‐1‐yl)methylidene]hydantoin‐Substituted Butane‐1,2‐diol
Authors: Aly Youssef Lotfy , Wamberg Michael , Pedersen Erik B.
Published: December 2005

Isopropylidene‐protected (S)‐4‐O‐(methylsulfonyl)butane‐1,2,4‐triol was used for alkylation of 5‐[(pyren‐3‐yl)methylidene]hydantoin to give the N3‐monoalkylated product 4 in 29% yield together with a dialkylated product 5 in 12% yield. After deprotection, compound 4 was transformed into a dimethoxytrityl (DMT)‐protected phosphoramidite building block 9 for standard DNA synthesis. When inserted as a bulge in the triplex‐forming oligomer, compound 6 stabilizes a DNA triplex, whereas the corresponding DNA/DNA and DNA/RNA duplexes are slightly destabilized. For the triplex, fluorescence enhancement was observed at 500 nm.
7‐Oxanorbornane and Norbornane Mimics of a Distorted β‐D‐Mannopyranoside: Synthesis and Evaluation as β‐Mannosidase Inhibitors
Authors: Buser Stephan , Vasella Andrea
Published: December 2005

The racemic 7‐oxanorbornanyl and norbornanyl aminoalcohols 3, 4, 42, 45, and 46 were synthesized and tested as snail β‐mannosidase inhibitors. The amino tetraol 3 was obtained from the known sulfonyl acrylate 9 and furan 10. Esterification provided 11 that underwent an intramolecular Diels–Alder reaction to the 7‐oxanorbornene 12. Reduction of 12 to 13, desulfonylation, isopropylidenation, and cis‐dihydroxylation gave 16. A second isopropylidenation to 17, followed by debenzylation and a Mitsunobu–Gabriel reaction provided 19 that was deprotected via 20 to 3. Diels–Alder cycloaddition of furfuryl acetate and maleic anhydride to 21, followed by alcoholysis of the anhydride, cis‐dihydroxylation, isopropylidenation, and Barton decarboxylation gave the ester 25. Deacetylation to 26 and a Mitsunobu–Gabriel reaction led to 27 that was transformed into the N‐Boc analogue 29, reduced to the alcohol 30, and deprotected to 4. The 1‐aminonorbornane 5 was obtained from Thiele's Acid 31. Diels–Alder cycloaddition of the cyclopentadiene obtained by thermolysis of the diester 32, methanolysis of the resulting anhydride 33, dihydroxylation, isopropylidenation, Barton decarboxylation, and Curtius degradation led to the benzyl carbamate 39 that was reduced to the alcohol 40, transformed into the N‐Boc carbamate 41, and deprotected to 5. The alcohol 40 was also transformed into the benzylamine 42, aniline 45, and hydroxylamine 46. Snail β‐mannosidase was hardly inhibited by 3, 4, 42, 45, and 46. Only the amino triol 5 proved a stronger inhibitor. The inhibition by 5 depends on the pH value (at pH 3.5: Ki = 1900 μM; at pH 4.5: Ki = 340 μm; at pH 5.5: Ki = 110 μm). The results illustrate the strong dependence of the inhibition by bicyclic mimics upon the precise geometry and orientation of the amino group as determined by the scaffold. It is in keeping with the hypothesis that the reactive conformation imposed by snail β‐mannosidase is close to a 1,4B/1S3.
Aminoreduktone – Untersuchungen an Verbindungen mit dem C‐Gerüst des Dimedons und mit sekundären Aminen als Bausteinen
Authors: Schank Kurt , Glock Rebecca , Lick Carlo
Published: December 2005

Aminoreductones – Investigations on Species Containing the Carbon Arrangement of Dimedone and Secondary Amines as Building Blocks
The ozonation of 3‐(sec‐amino)‐5,5‐dimethylcyclohex‐2‐en‐1‐ones 4 was compared with the corresponding acyloxylations by diacylperoxides 5, making accessible 3‐(sec‐amino)‐reductones 9. Both types of oxygenation also led to higher‐oxygenated six‐ring carbocyclic products (7, 8, 17), ozonation being a minor reaction path, in addition to CC cleavage. The corresponding 2‐(sec‐amino)reductones 34 were generated via aminolysis of the iodonium intermediate 44 (Scheme 13), and their reductive behavior against t‐BuOCl and 3‐chloroperbenzoic acid (MCPBA) as oxidizing agents was compared. Attempts to generate the corresponding reductone 5,5‐dimethyl‐2,3‐dimorpholin‐4‐ylcyclohex‐2‐en‐1‐one (45) were unsuccessful (Scheme 13). Instead, the corresponding iodonium intermediate 44 suffered a Favorskii‐like regioselective ring contraction during aminolysis, followed by autoxidation. These unexpected reactions were confirmed by separate experiments.
Synthesis of Nonsymmetrically N,N′‐Diaryl‐Substituted 4,4′‐Bipyridinium Salts with Redox‐Tunable and Titanium Dioxide (TiO2)‐Anchoring Properties
Authors: Bongard Dirk , Möller Martin , Rao S. Nagaraja , Corr David , Walder Lorenz
Published: December 2005

A general method for the synthesis of so far unknown nonsymmetrically substituted N‐aryl‐N′‐aryl′‐4,4′‐bipyridinium salts is presented (Scheme 1). The common intermediate in all procedures is N‐(2,4‐dinitrophenyl)‐4,4′‐bipyridinium hexafluorophosphate (1 ⋅ $\rm{\rm PF_6^ -}$). For the synthesis of nonsymmetric arylviologens, 1 ⋅ $\rm{\rm PF_6^ -}$ was arenamine‐exchanged by the Zincke reaction, and then activated at the second bipyridine N‐atom with 2,4‐dinitrophenyl 4‐methylbenzenesulfonate. The detailed preparation of the six N‐aryl‐N′‐aryl′‐viologens 21–26 is discussed (Scheme 2). The generality of the procedure is further exemplified by the synthesis of two nonsymmetrically substituted N‐aryl‐N′‐benzyl‐ (see 11 and 12), and seven N‐aryl‐N′‐alkyl‐4,4′‐bipyridinium salts (see 28–34) including substituents with metal oxide anchoring and redox tuning properties. The need for these compounds and their usage as electrochromic materials, in dendrimer synthesis, in molecular electronics, and in tunable‐redox mediators is briefly discussed. The latter adjustable property is demonstrated by the reduction potential measured by cyclic voltammetry on selected compounds (Table).
Synthesis and Properties of Oligonucleotides Containing 2,4‐Dihydroxycyclohexyl Nucleosides
Authors: Bardiot Dorothée , Rosemeyer Helmut , Lescrinier Eveline , Rozenski Jef , Van Aerschot Arthur , Herdewijn Piet
Published: December 2005

Cyclohexyl nucleosides with an adenine and uracil base have been synthesized from 2‐azidocyclohexane‐1,5‐diol. The obtained racemic nucleosides were resolved using (R)‐O‐methylmandelic acid. Short oligonucleotides were synthesized using phorphoramidite chemistry. However, these oligonucleotides do not show self‐hybridization, and duplexes are less stable than those of ribopyranosyl‐(4′ → 2′)‐oligonucleotides.
Acetogenins from the Leaves of Rollinia laurifolia
Authors: Pimenta Lucia P. S. , Nascimento Francisco C. , Boaventura Maria Amélia D.
Published: December 2005

From the EtOH extract of the leaves of Rollinia laurifolia Schl. (Annonaceae), a novel acetogenin, rolifolin (= 3‐(9‐{(2R*,5S*)‐5‐[(1S*,4S*)‐1,4‐dihydroxy‐4‐{(2S*,5R*)‐5‐[(1S*)‐1‐hydroxyundecyl]tetrahydrofuran‐2‐yl}butyl]tetrahydrofuran‐2‐yl}‐2,3‐dihydroxynonyl)‐5‐methylfuran‐2(5H)‐one; 1) was isolated, together with the known acetogenin annonin‐I (2). Also, from the corresponding hexane extract, a mixture of rolilaurin (3, a novel compound), uvariamicin‐I (4), and uvariamicin‐II (5) was obtained. The structures of compounds 1–5 were elucidated by NMR and MS analysis, and relative configurations were established. Compounds 2 and 5 have never been obtained before from Rollinia.
Synthesis of a Fusion‐Isomeric Cellobionoimidazole and Its Evaluation against the syn‐Protonating Glycosidase Cel7A
Authors: Mohal Narinder , Bernet Bruno , Vasella Andrea
Published: December 2005

The fusion‐isomeric cellobinoimidazole 2, a potential inhibitor of the syn‐protonating β‐glycosidase Cel7A, was synthesised by Koenigs–Knorr glycosylation of the α‐D‐arabinopyranoside 32, followed by selective hydrolysis. Glycosylation of 32 with acetobromoglucose 6 proceeded with poor diastereoselectivity, giving the desired 1,3‐linked β‐d‐disaccharide 35 as minor product, besides the major 1,3‐linked α‐d‐disaccharide 36. Hg2+‐Promoted glycosylation of 32 led predominantly to the 1,2‐ortho ester 33. Sequential removal of the silyl, acetyl, and allyl groups of 35 led to a 45 : 55 equilibrium mixture 2 and the manno‐configured isomer 39. Similarly, deprotection of 36 gave a mixture of the maltonoimidazole 42 and the manno‐configured isomer 43. According to a known protocol, the glycosyl acceptor 32 was synthesised in eleven steps and an overall yield of 8–13% from D‐lyxose. The silylated arabinopyranosyl moiety of the α‐d‐glucosides 13–19, 33, 34, and 36 adopts a 4C1 conformation, while the arabinopyranosyl moiety of the β‐d‐glucosides 17 and 35 exists as a 1 : 3 mixture of 4C1 and 1C4 conformers, as a result of the combined preferred axial orientation of bulky vicinal substituents and the anomeric effect. MM3* Modelling evidences a preferred 4C1 conformation of 35 and 36, and stronger steric interactions between the pyranosyl moieties of 35. The equilibrium mixture 2/39 proved a poor inhibitor of Cel7A with an IC50 value of ca. 4 mM.
Ring Enlargement and Sulfur‐Transfer Processes in SiO2‐Catalyzed Reactions of Thiocarbonyl Compounds with Optically Active Oxiranes
Authors: Malaschichin Sergej , Fu Changchun , Linden Anthony , Heimgartner Heinz
Published: December 2005

The reactions of 1,3‐dioxolane‐2‐thione (3) with (S)‐2‐methyloxirane ((S)‐1) and with (R)‐2‐phenyloxirane ((R)‐2) in the presence of SiO2 in anhydrous dichloroalkanes led to the optically active spirocyclic 1,3‐oxathiolanes 8 with Me at C(7) and 9 with Ph at C(8), respectively (Schemes 2 and 3). The analogous reaction of 1,3‐dimethylimidazolidine‐2‐thione (4a) with (R)‐2 yielded stereoselectively (S)‐2‐phenylthiirane ((S)‐10) in 83% yield and 97% ee together with 1,3‐dimethylimidazolidin‐2‐one (11a). In the cases of 3‐phenyloxazolidine‐2‐thione (4b) and 3‐phenylthiazolidine‐2‐thione (4c), the reaction with (RS)‐2 yielded the racemic thiirane (RS)‐10, and the corresponding carbonyl compounds 11b and 11c (Scheme 4 and Table 1). The analogous reaction of 4a with 1,2‐epoxycyclohexane (= 7‐oxabicyclo[4.1.0]heptane; 7) afforded thiirane 12 and the corresponding carbonyl compound 11a (Scheme 5). On the other hand, the BF3‐catalyzed reaction of imidazolidine‐2‐thione (5) with (RS)‐2 yielded the imidazolidine‐2‐thione derivative 13 almost quantitatively (Scheme 6). In a refluxing xylene solution, 1,3‐diacetylimidazolidine‐2‐thione (6) and (RS)‐2 reacted to give two imidazolidine‐2‐thione derivatives, 13 and 14 (Scheme 7). The structures of 13 and 14 were established by X‐ray crystallography (Fig.).
Synthesis and Stereochemical Aspects of Ethyl 1,1a,2,3,4,5,6,6a‐Octahydro‐4‐octylcyclopropa[f]indene‐1‐carboxylate
Authors: Hussain Zakir , Koley Debasis , Hopf Henning
Published: December 2005

A novel approach for the synthesis of carbene adducts 9a/9b and 10/11 is reported. Identification of the geometric and positional isomers of carbene addition was carried out by reversed‐phase HPLC, and the establishment of the structure and configuration of 9a/9b was performed by means of 2D‐NMR.
Cancer incidence in the age range 0–34 years: Historical and actual status in Denmark
Authors: van der Horst Mirjam , Winther Jeanette Falck , Olsen Jørgen H.
Published: December 2005

On the basis of 55 years of continuous cancer registration in Denmark, we present cancer incidence rates, time trends and birth cohort analyses for persons aged 0–34 years. The group of 40,750 cancer patients showed a substantial over‐representation of males aged 1–24 years. The cancer pattern among young (15–34 years) men was dominated by testicular cancer (35%), lymphomas (14%) and tumors of the brain (13%), while the pattern among young women was governed by invasive cervical cancer (19%), malignant melanoma (15%) and cancer of the breast (12%). In this age range, a positive time trend was seen after 1970, equivalent to average annual percentage increases of 1.9% for men and 1.8% for women, due mainly to markedly increasing trends for testicular cancer, malignant melanoma, brain tumors, thyroid cancer, skin carcinomas and skin sarcoma among men, and for brain tumors, non‐Hodgkin lymphoma, malignant melanoma, skin carcinomas and thyroid cancer among women. We saw no clear time trend for breast cancer among women. The cancer pattern among children (0–14 years) was similar to that reported for other white populations. © 2005 Wiley‐Liss, Inc.
Incidence trends and projections for childhood cancer in Ontario
Authors: Agha Mohammed , DiMonte Bruna , Greenberg Mark , Greenberg Corin , Barr Ronald , McLaughlin John R.
Published: December 2005

Studies of cancer incidence patterns and trends can provide useful measures of health burden and possible disease etiology, which can aid the planning of cancer care services. This report aims to characterize trends in incidence of childhood cancer, and to assess the implications of these trends by generating incidence projections to 2015. Cancer incidence data were obtained from the database of the Pediatric Oncology Group of Ontario (POGO), which has registered all cancer cases in Ontario since 1985. Annual incidence rates were calculated with census‐based population estimates for the 1986–2001 period. Poisson regression models were used to analyze trends, and to calculate projected numbers of cases up to the year 2015. From 1986 to 2001, 5,163 cancer cases occurred among children aged 0–14. Leukemia, CNS tumors and lymphomas were the most common cancers. The number of incident cases increased by 14%, from 296 in 1986 to 336 in 2001. For all cancers, average annual age‐standardized rates increased from 147 per million in 1991 to 157 per million in 2001. Over the next 15 years, the 0–14 year population is expected to decrease from 2.28 million in 2000 to 2.13 million in 2015. A marginally statistically significant trend in incidence was projected for all cancers combined (0.5% increase per year p < 0.10) and a statistically significant increase for lymphomas, (1.2% per year 95% CI = 0.0–3.9%). During this period, the number of cases of leukemia and CNS tumors is expected to remain relatively stable. The number of cases of all cancers is expected to increase by 8%, from the average of 320 in 1995 to ∼347 in 2015. Understanding of these projections will facilitate health care resource planning. © 2005 Wiley‐Liss, Inc.
Calcitonin stimulates the secretion of urokinase‐type plasminogen activator from prostate cancer cells: Its possible implications on tumor cell invasion
Authors: Sabbisetti Venkata , Chigurupati Srinivasulu , Thomas Shibu , Shah Girish
Published: December 2005

Calcitonin (CT) is synthesized and secreted in prostate epithelium, and its secretion from malignant prostates is several folds higher than that in benign prostates. CT receptor (CTR) is expressed in malignant prostate epithelium, and its activation increases invasiveness of prostate cancer (PC) cells via activation of protein kinase A. Since the role of urokinase‐type plasminogen activator (uPA) in invasion of PC has been established, we tested the hypothesis that CT increases invasion of PC cells by stimulating uPA secretion from PC cells. Exogenously added CT stimulated the secretion of uPA from PC‐3M cells in a dose‐dependent manner, which was blocked by Rp.cAMP, a competitive inhibitor of protein kinase A. CT stimulated the secretion of MMP‐2 and MMP‐9 from PC‐3M cells, and also increased their invasiveness. Both these actions of CT were blocked by uPA‐neutralizing antibodies. Immunofluorescence studies with PC‐3M cells suggest that CT stimulated redistribution of cellular uPA to focal adhesion sites, which was further confirmed by co‐immunoprecipitation of uPA with focal adhesion kinase (FAK) in response to CT. These results suggest that CT increases invasiveness of PC cells by stimulating PKA‐mediated uPA secretion and by redirecting the secreted uPA to focal adhesion sites. The results also suggest that uPA may, at least in part, mediate proinvasive actions of CT on PC cells by stimulating the secretion of gelatinases and degradation of focal adhesion sites. © 2005 Wiley‐Liss, Inc.