bluuebunny/crossref_metadata_2025 huggingface dataset:
α-Chain phosphorylation of the human leukocyte CD11b/CD18 (Mac-1) integrin is pivotal for integrin activation to bind ICAMs and leukocyte extravasation
Authors: Fagerholm Susanna C. , Varis Minna , Stefanidakis Michael , Hilden Tiina J. , Gahmberg Carl G.
Published: July 2006

The promiscuous CD11b/CD18 (Mac-1) integrin has important roles in regulating many immunologic functions such as leukocyte adhesion and emigration from the bloodstream via interactions with the endothelial ligands ICAM-1 and ICAM-2, iC3b-mediated phagocytosis, and apoptosis. However, the mechanisms for Mac-1 inside-out activation have remained poorly understood. Phosphorylation of integrin cytoplasmic domains is emerging as an important mechanism of regulating integrin functions. Here, we have studied phosphorylation of human CD11b, which takes place on the cytoplasmic Ser1126 in neutrophils. We show that mutation of the serine phosphorylation site leads to inability of Mac-1 to become activated to bind the cellular ligands ICAM-1 and ICAM-2. However, CD11b-mutant cells are fully capable of binding other studied CD11b ligands (ie, iC3b and denatured BSA). Activation epitopes expressed in the extracellular domain of the integrin and affinity for soluble ICAM ligands were decreased for the mutated integrin. Additionally, the mutation resulted in inhibition of chemokine-induced migration in a transendothelial assay in vitro and significantly reduced the accumulation of intravenously administered cells in the spleen and lungs of Balb/c mice. These results characterize a novel selective mechanism of Mac-1–integrin activation, which mediates leukocyte emigration from the bloodstream to the tissues.
Plasma inhibitory activity (PIA): a pharmacodynamic assay reveals insights into the basis for cytotoxic response to FLT3 inhibitors
Authors: Levis Mark , Brown Patrick , Smith B. Douglas , Stine Adam , Pham Rosalyn , Stone Richard , DeAngelo Daniel , Galinsky Ilene , Giles Frank , Estey Elihu , Kantarjian Hagop , Cohen Pamela , Wang Yanfeng , Roesel Johannes , Karp Judith E. , Small Donald
Published: July 2006

We have developed a useful surrogate assay for monitoring the efficacy of FLT3 inhibition in patients treated with oral FLT3 inhibitors. The plasma inhibitory activity (PIA) for FLT3 correlates with clinical activity in patients treated with CEP-701 and PKC412. Using the PIA assay, along with in vitro phosphorylation and cytotoxicity assays in leukemia cells, we compared PKC412 and its metabolite, CGP52421, with CEP-701. While both drugs could effectively inhibit FLT3 in vitro, CEP-701 was more cytotoxic to primary samples at comparable levels of FLT3 inhibition. PKC412 appears to be more selective than CEP-701 and therefore less effective at inducing cytotoxicity in primary acute myeloid leukemia (AML) samples in vitro. However, the PKC412 metabolite CGP52421 is less selective than its parent compound, PKC412, and is more cytotoxic against primary blast samples at comparable levels of FLT3 inhibition. The plasma inhibitory activity assay represents a useful correlative tool in the development of small-molecule inhibitors. Our application of this assay has revealed that the metabolite CGP52421 may contribute a significant portion of the antileukemia activity observed in patients receiving oral PKC412. Additionally, our results suggest that nonselectivity may constitute an important component of the cytotoxic effect of FLT3 inhibitors in FLT3-mutant AML.
Enumeration of leukocyte infiltration in solid tumors by confocal laser scanning microscopy
Authors: Biggerstaff J , Weidow B , Amirkhosravi A , Francis JL
Published: July 2006

Background

Leukocytes commonly infiltrate solid tumors, and have been implicated in the mechanism of spontaneous regression in some cancers. Conventional techniques for the quantitative estimation of leukocyte infiltrates in tumors rely on light microscopy of immunostained thin tissue sections, in which an arbitrary assessment (based on low, medium or high levels of infiltration) of antigen density is made by the pathologist. These estimates are relatively subjective and often require the opinion of a second pathologist. In addition, since thin tissue sections are cut, no data regarding the three-dimensional distribution of antigen can be obtained.

Results

To overcome these problems, we have designed a method to enumerate leukocyte infiltration into tumors, using confocal laser scanning microscopy of fluorescently immunostained leukocytes in thick tissue sections. Using image analysis software, a threshold was applied to eliminate unstained tissue and residual noise. The total antigen volume in the scanned tissue was calculated and divided by the mean cell volume (calculated by "seeding" ten individual cells) to obtain the cell count. Using this method, we compared the calculated leukocyte counts with those obtained manually by ten laboratory personnel. There was no significant difference (P > 0.05) between the cell counts obtained by either method.

We then compared leukocyte infiltration into seven tumors and matched non-malignant tissue obtained from the periphery of the resected tissue. There was a significant increase in the infiltration of all leukocyte subsets into the tumors compared to minimal numbers in the non-malignant tissue.

Conclusion

From these results we conclude that this method may be of considerable use for the enumeration of cells in tissues. Furthermore, since it can be performed by laboratory technical staff, less time input is required by the pathologist in assessing the degree of leukocyte infiltration into tumors.
Political dynamics promoting the incremental regulation of secondhand smoke: a case study of New South Wales, Australia
Authors: Bryan-Jones Katherine , Chapman Simon
Published: July 2006

Background

The history of governmental responses to the accumulation of scientific evidence about the harms of secondhand smoke (SHS) presents an intriguing case study of incremental public health policy development. Australia has long been considered a world-leader in progressive tobacco control policies, but in the last decade has fallen behind other jurisdictions in introducing SHS legislation that protects all workers. Bars, clubs and pubs remain the only public indoor spaces where smoking is legally permitted, despite SHS exposure in the hospitality industry being higher and affecting more people than in any other setting after domestic exposure. This paper examines the political dynamics that have shaped this incremental approach to SHS.

Methods

In-depth interviews with 21 key stakeholders in the state of New South Wales (NSW), including politicians, their advisors, health officials and tobacco control advocates, were conducted and subjected to thematic content analysis. Interviewees' comments provided insights into the dynamics surrounding the debates and outcomes of SHS legislative attempts and the current political environment, and about how to progress SHS legislation.

Results

SHS restrictions have been delayed by several broad factors: the influence of industry groups successfully opposing regulation; issue wear-out; and political perceptions that there is not a salient constituency demanding that smoking be banned in bars and clubs. Interviewees also provided suggestions of strategies that advocates might utilise to best overcome the current political inertia of incremental compromises and achieve timely comprehensive smoking bans.

Conclusion

Advocates concerned to shorten the duration of incremental endgames must continue to insist that governments address SHS fundamentally as a health issue rather than making political concessions to industry groups, and should broaden and amplify community voices calling on governments to finish the job. Publicity to the growing number of state and national governments that have successfully implemented total bans over the past decade is likely to make incrementalism an increasingly unattractive political option.
A novel approach to measure the contribution of matrix metalloproteinase in the overall net proteolytic activity present in synovial fluids of patients with arthritis
Authors: Simard Nathalie , Boire Gilles , de Brum-Fernandes Artur J , St-Pierre Yves
Published: July 2006

Despite decades of research, only a very limited number of matrix metalloproteinase (MMP) inhibitors have been successful in clinical trials of arthritis. One of the central problems associated with this failure may be our inability to monitor the local activity of proteases in the joints since the integrity of the extracellular matrix results from an equilibrium between noncovalent, 1:1 stoichiometric binding of protease inhibitors to the catalytic site of the activated forms of the enzymes. In the present work, we have measured by flow cytometry the net proteolytic activity in synovial fluids (SF) collected from 95 patients with osteoarthritis and various forms of inflammatory arthritis, including rheumatoid arthritis, spondyloarthropathies, and chronic juvenile arthritis. We found that SF of patients with inflammatory arthritis had significantly higher levels of proteolytic activity than those of osteoarthritis patients. Moreover, the overall activity in inflammatory arthritis patients correlated positively with the number of infiltrated leukocytes and the serum level of C-reactive protein. No such correlations were found in osteoarthritis patients. Members of the MMP family contributed significantly to the proteolytic activity found in SF. Small-molecular-weight MMP inhibitors were indeed effective for inhibiting proteolytic activity in SF, but their effectiveness varied greatly among patients. Interestingly, the contribution of MMPs decreased in patients with very high proteolytic activity, and this was due both to a molar excess of tissue inhibitor of MMP-1 and to an increased contribution of other proteolytic enzymes. These results emphasize the diversity of the MMPs involved in arthritis and, from a clinical perspective, suggest an interesting alternative for testing the potential of new protease inhibitors for the treatment of arthritis.
Epratuzumab (humanised anti-CD22 antibody) in primary Sjögren's syndrome: an open-label phase I/II study
Authors: Steinfeld Serge D , Tant Laure , Burmester Gerd R , Teoh Nick KW , Wegener William A , Goldenberg David M , Pradier Olivier
Published: July 2006

This open-label, phase I/II study investigated the safety and efficacy of epratuzumab, a humanised anti-CD22 monoclonal antibody, in the treatment of patients with active primary Sjögren's syndrome (pSS). Sixteen Caucasian patients (14 females/2 males, 33–72 years) were to receive 4 infusions of 360 mg/m2 epratuzumab once every 2 weeks, with 6 months of follow-up. A composite endpoint involving the Schirmer-I test, unstimulated whole salivary flow, fatigue, erythrocyte sedimentation rate (ESR), and immunoglobulin G (IgG) was devised to provide a clinically meaningful assessment of response, defined as a ≥20% improvement in at least two of the aforementioned parameters, with ≥20% reduction in ESR and/or IgG considered as a single combined criterion. Fourteen patients received all infusions without significant reactions, 1 patient received 3, and another was discontinued due to a mild acute reaction after receiving a partial infusion. Three patients showed moderately elevated levels of Human anti-human (epratuzumab) antibody not associated with clinical manifestations. B-cell levels had mean reductions of 54% and 39% at 6 and 18 weeks, respectively, but T-cell levels, immunoglobulins, and routine safety laboratory tests did not change significantly. Fifty-three percent achieved a clinical response (at ≥20% improvement level) at 6 weeks, with 53%, 47%, and 67% responding at 10, 18, and 32 weeks, respectively. Approximately 40%–50% responded at the ≥30% level, while 10%–45% responded at the ≥50% level for 10–32 weeks. Additionally, statistically significant improvements were observed in fatigue, and patient and physician global assessments. Further, we determined that pSS patients have a CD22 over-expression in their peripheral B cells, which was downregulated by epratuzumab for at least 12 weeks after the therapy. Thus, epratuzumab appears to be a promising therapy in active pSS, suggesting that further studies be conducted.
Extrapulmonary manifestations of severe respiratory syncytial virus infection – a systematic review
Authors: Eisenhut Michael
Published: July 2006

Introduction

Respiratory syncytial virus (RSV) bronchiolitis is the most important cause for admission to the paediatric intensive care unit in infants with lower respiratory tract infection. In recent years the importance of extrapulmonary manifestations of RSV infection has become evident. This systematic review aimed at summarizing the available evidence on manifestations of RSV infection outside the respiratory tract, their causes and the changes in clinical management required.

Methods

Databases searched were Medline (1950 to present), EMBASE (1974 to present), PubMed and reference lists of relevant articles. Summarized were the findings of articles reporting on manifestations of RSV infection outside the respiratory tract in patients of all age groups.

Results

Extrapulmonary manifestations reported in previous observational studies included cardiovascular failure with hypotension and inotrope requirements associated with myocardial damage as evident from elevated cardiac troponin levels (35–54% of ventilated infants), cardiac arrhythmias like supraventricular tachycardias and ventricular tachycardias, central apnoeas (16–21% of admissions), focal and generalized seizures, focal neurological abnormalities, hyponatraemia (33%) associated with increased antidiuretic hormone secretion, and hepatitis (46–49% of ventilated infants). RSV or its genetic material have been isolated from cerebrospinal fluid, myocardium, liver and peripheral blood.

Conclusion

The data summarized indicate a systemic dissemination of RSV during severe disease. Cerebral and myocardial involvement may explain the association of RSV with some cases of sudden infant death. In infants with severe RSV infection cardiac rhythm, blood pressure and serum sodium need to be monitored and supportive treatment including fluid management adjusted accordingly.
Functional and phenotypic analysis of human memory CD8+ T cells expressing CXCR3
Authors: Kobayashi Naoki , Kondo Takaaki , Takata Hiroshi , Yokota Shumpei , Takiguchi Masafumi
Published: July 2006

Several chemokine receptors play an important role in the migration of naïve, memory, and effector T cells. Flow cytometric analyses showed that human CD8+ T cells with naïve (CD27+CD28+CD45RA+) or memory (CD27+CD28+/−CD45RA+) phenotypes included a population expressing a high level of CXC chemokine receptor 3 (CXCR3high) and one expressing a low level of it (CXCR3low), but those with the effector phenotype (CD27−CD28−CD45RA+/−) included a population that did not express CXCR3 (CXCR3−) and a CXCR3low population. This relation between the expression level of CXCR3 and memory/effector phenotypes also applied to Epstein-Barr virus- or human cytomegalovirus-specific CD8+ T cells. CXCR3high cells were found predominantly in CC chemokine receptor 7 (CCR7)+CCR5− and CCR7−CCR5− subsets of CD8+ T cells with the CD27+CD28+CD45RA− memory phenotype, suggesting that they are memory cells with intermediate differentiation. Indeed, CXCR3highCD27+CD28+CD45RA−CD8+ T cells had the ability to produce interleukin-2 and interferon-γ. These results together indicate that the expression of CXCR3 is up-regulated on intermediately differentiated memory CD8+ T cells. CXCR3highCD8+ T cells had a greater ability to migrate in response to CXCR3 ligands than CXCR3low ones. As CXCR3high memory CD8+ T cells do not express CCR5, high expression of CXCR3 on these memory CD8+ T cells might play an important role in the migration of these cells to inflammatory sites and in their differentiation.
Localization and Characterization of an Orphan Receptor, Guanylyl Cyclase-G, in Mouse Testis and Sperm
Authors: Huang Yen-Hua , Wei Chih-Chun , Su Yueh-Hsing , Wu Bo-Tsung , Ciou Yi-Yun , Tu Cheng-Fen , Cooper Trevor G. , Yeung Ching-Hei , Chu Sin-Tak , Tsai Ming-Tzu , Yang Ruey-Bing
Published: July 2006

We recently identified a novel testis-enriched receptor guanylyl cyclase (GC) in the mouse, designated mGC-G. To further investigate its protein expression and function, we generated a neutralizing antibody specifically against the extracellular domain of this receptor. RT-PCR and immunohistochemical analyses show that mGC-G is predominantly expressed from round spermatids to spermatozoa in mouse testis at both the mRNA and protein levels. Flow cytometry and confocal immunofluorescence reveal that mGC-G is a cell surface protein restricted to the plasma membrane overlying the acrosome and midpiece of the flagellum in mature sperm. Interestingly, Western blot analysis demonstrates that testicular mGC-G is approximately 180 kDa but is subject to limited proteolysis during epididymal sperm transport, resulting in a smaller fragment tethered on the mature sperm surface. On Fluo-3 cytometrical analysis and computer-assisted sperm assay, we found that serum albumin-induced elevation of sperm intracellular Ca2+ concentration, protein tyrosine phosphorylation, and progressive motility associated with capacitation are markedly reduced by preincubation of the anti-mGC-G neutralizing antibody. Together, these results indicate that mGC-G is proteolytically modified in mature sperm membrane and suggest that mGC-G-mediated signaling may play a critical role in gamete/reproductive biology.
Habit Modification of a Diastereomeric Salt with an Additive in Optical Resolution
Authors: Sakai Kenichi , Maekawa Yasunari , Saigo Kazuhiko , Sukegawa Makoto , Murakami Hisamichi , Nohira Hiroyuki
Published: July 2006

In the optical resolution of α-methylbenzylamine (1) with mandelic acid (2), the dimeric derivative of 1, bis(α-methylbenzyl)amine (4), caused a habit modification of the diasteromeric salt, (R)-1·(R)-2 (3). The habit modification was strongly influenced by the stereochemistry of 4. Amine (R,R)-4 changed the morphology of the crystal of the diastereomeric salt, even at a concentration of 0.007 mol% of 3; the shape of the crystal became a hexagonal plate from a long hexagonal plate, whereas its stereoisomer ((R,S)-4) changed the morphology less than (R,R)-4, and (S,S)-4 did not change at all. The habit modification of 3 by 4 is discussed on the basis of the crystal growth mechanism while considering the stereochemistry of 4.
Pyrrolizidine Alkaloids. The Synthesis and Absolute Configuration of All Stereoisomers of 4-Carboxy-4-ethyl-3-hydroxy-2-isopropyl-4-butanolide, the Necic Acid Component of Axillaridine
Authors: Matsumoto Takashi , Terao Hiromitsu , Ishizuka Natsuki , Usui Shuji , Nozaki Hiroshi
Published: July 2006

All stereoisomers (4a,b–7a,b) of 4-carboxy-4-ethyl-3-hydroxy-2-isopropyl-4-butanolide, the necic acid component of axillaridine, have been synthesized. Methyl(E)-(S)-(+)-2-ethyl-4-methoxycarbonyl-5-methyl-2- hexenoate (12a) was converted into γ-lactone acids, 4a (2S,3S,4S), 5a (2S,3R,4R), and 5b (2R,3S,4S), by a series of reactions: Epoxidation with m-chloroperbenzoic acid, treatment with acetone in the presence of tin(IV) chloride, acidic hydrolysis with formic acid, and alkaline hydrolysis with barium hydroxide. Similarly, (R)-(−)-enantiomer (12b) was also transformed into γ-lactone acids 4b (2R,3R,4R), 5b and 5a. Subsequently, (E)-(S)-(+)-4-carboxy-2-ethyl-5-methyl-2-hexenoic acid (13a) and its (R)-(−)-enantiomer (13b) were esterified with chloromethyl methyl ether in the presence of triethylamine to give the corresponding bis(methoxymethyl) esters (26a and 26b). Oxidation of 26a with potassium permanganate and subsequent acidic hydrolysis afforded γ-lactone acids, 6a (2S,3R,4S) and 7a (2S,3S,4R). Similarly, ester 26b was also converted into 6b (2R,3S,4R) and 7b (2R,3R,4S). The stereochemical courses of the above-mentioned trans- and cis-hydroxylations of olefinic esters (12a,b and 26a,b) were well explained by applying the Felkin–Anh model. The CD spectra of the synthetic 4a,b–7a,b are also discussed.
Chemical Behavior of Aromatic Radical Cations under Superoxide-Free Electron Transfer Photooxygenation Conditions
Authors: Futamura Shigeru
Published: July 2006

The electron transfer photooxygenations of aromatic compounds were carried out with trityl salts. Under these superoxide-free reaction conditions, only anthracene and 1,1-diarylethylenes were photooxygenated, stilbenes isomerized, and quantitatively recovered were naphthalene, phenanthrene, alkylnaphthalenes, tetraphenylethylene and 1,1,4,4-tetraaryl-1,3-butadienes. The reactivities of their radical cations toward triplet oxygenation were discussed on the basis of the quantum yield measurements and product analyses.
Cycloaddition Reactions of 2-Acetylamino-, 2-Alkylamino-, 8-Ethylamino-, and 8-Acetylamino-1-azaazulenes with Dimethyl Acetylenedicarboxylate
Authors: Abe Noritaka , Fukazawa Yoshimasa , Hirai Yoshimasa , Sakurai Tosio , Urushido Kunio , Kakehi Akikazu
Published: July 2006

The reactions of 2- and 8-(substituted amino)-1-azaazulenes with dimethyl acetylenedicarboxylate (DMAD) were investigated. Treatment of ethyl 2-acetylamino-1-azaazulene-3-carboxylate with DMAD in refluxing acetonitrile gave 9-ethyl 1,2,3-trimethyl 3a-azacyclopent[a]azulene-1,2,3,9-tetracarboxylate, 5-ethyl 1,2,2a,3-tetramethyl 4-acetyl-2a,3-dihydro-4H-4, 10b-diazapentaleno[1,6-aj]azulene-1,2,2a,3,5-pentacarboxylate (3a), and dimethyl (10-ethoxycarbonyl-4-methoxycarbonyl-2,4a-dihydro-2-oxo-2H-1,4a-diazabenz[a]azulen-3-yl)maleate. Compound 3a thermally rearranged to 9-ethyl 2,3,10,11-tetramethyl 1-acetyl-2,3,4,4a-tetrahydro-1H-1,4-diaza-3,4a-ethenofluorene-2,3,9,10,11-pentacarboxylate. The reaction of ethyl 2-alkylamino-1-azaazulene-3-carboxylate with DMAD gave the corresponding 4-alkyl-2a,3-dihydro-4H-4,10b-diazapentaleno[1,6-aj]azulene derivatives, and the etheno-bridged 1-azaheptalene derivative. The reaction of 8-ethylamino-3-phenyl-1-azaazulene with DMAD gave trimethyl 1-phenyl-2a-azabenz[cd]azulene-3,4,5-tricarboxylate, tetramethyl 6-ethyl-1-phenyl-4a,5-dihydro-6H-2a,6-diazapentaleno[1,6-cd]azulene-3,4,4a,5-tetracarboxylate, tetramethyl 3-phenyl-9b-azaindeno[1,6,7-bcd]azulene-1,2,8,9-tetracarboxylate, and dimethyl [8-phenyl-1,2,3-tris(methoxycarbonyl)-8H-3a-azacyclopent[1,2-a]inden-8-yl]maleate. However, the reaction of 8-acetylamino-3-phenyl-1-azaazulene with DMAD gave dimethyl-1-phenyl-2a,5-diazabenz[cd]azulene-3,4-dicarboxylate, trimethyl 3-phenyl-8,9b-diazaindeno[1,6,7-bcd]azulene-1,2,9-tricarboxylate, dimethyl 3-phenyl-8,9b-diazaindeno[1,6,7-bcd]azulene-1,2-dicarboxylate, tetramethyl 6-acetyl-1-phenyl-4a,5-dihydro-6H-2a,6-diazapentaleno[1,6,7-cd]azulene-3,4,4a,5-tetracarboxylate. The structures of the obtained compounds were determined by inspections of their physical and spectral data, and by single-crystal X-ray analyses of some of these compounds. The reaction mechanisms of these reactions are discussed.
Synthesis of Novel Polycyclic Selenepinone Compounds
Authors: Sakakibara Makoto , Mizumoto Takahiro , Watanabe Yoshihiko , Toru Takeshi , Ueno Yoshio
Published: July 2006

Novel polycyclic selenepinone compounds, benzo[b]naphtho[2,3-f]selenepin-6,11,13(12H)-trione (6) and 6,14-dimethoxybenzo[1,2-b:5,4-b′]bis[1]benzoselenepin-12,16(13H,15H)-dione (14) were synthesized from chloroquinones.
Structure of Intramolecular Boron–Amine Complexes and Proposal of Tetrahedral Character for Correlation between Molecular Structure and Barrier to Dissociation of the N–B Bonds
Authors: Toyota Shinji , Oki Michinori
Published: July 2006

The molecular structures of a set of intramolecular boron-amine complexes, 9-[2-(dialkylaminomethyl)phenyl]-9-borabicyclo[3.3.1]nonanes (alkyl = Me and Et) and 2-[2-(dimethylaminomethyl)phenyl]-4,4-diphenyl-1,3,2-dioxaborolane, were determined by the X-ray analyses. The boron atom has a tetrahedral geometry and the five-membered ring is puckered with the nitrogen atom out of the plane in every complex. The distances of the N–B coordination bonds, which are in the range of 1.74–1.77Å, are not always correlated to the barrier to dissociation of the N–B bonds. In order to correlate the molecular structures to the strength of the N–B coordination bonds, the tetrahedral character, which is calculated from bond angles at a boron atom, is proposed. The usefulness as well as the limitation of this parameter are discussed.
Stereoselective Synthesis of (±)-Ireland Alcohol Using Titanium-Mediated [2,3]Wittig Rearrangement Product as a Starting Material
Authors: Ikegami Satoru , Okamura Hiroaki , Kuroda Satoru , Katsuki Tsutomu , Yamaguchi Masaru
Published: July 2006

The synthesis of (±)-Ireland alcohol, a key intermediate for the synthesis of tirandamycin A, was achieved in a straightforward manner by using isopropyl (2R*, 3S*, 4E)-6-benzyloxy-2-hydroxy-3-methyl-4-hexenoate as a starting material, which was readily obtained by the [2,3]Wittig rearrangement of isopropyl [(E)-1-benzyloxymethyl-2-butenyloxy]acetate via its titanium enolate.
One-Pot Synthesis and Redox Properties of Conjugation-Extended 4,4′-Bipyridines and Related Compounds. New Ligands Consisting of a Heterocyclic Three-Ring Assembly
Authors: Takahashi Kazuko , Nihira Takayasu
Published: July 2006

Dipyridyl-substituted heterocycles such as 2,5-di(4-pyridyl)thiophene 3, 2,5-di(4-pyridyl)furan 4, 2,5-di(4-pyridyl)thieno[3,2-b]thiophene 7, 1,4-di(4-pyridyl)benzene 6, 2,5-di(2-pyridyl)thiophene 8, and 2,5-di(3-pyridyl)thiophene 9 have been efficiently synthesized by a simple one-pot procedure through the palladium-mediated cross-coupling reaction between (trimethylstannyl)pyridines and dibromo-substituted heteroaromatics. The spectroscopic data (IR, 1H NMR, 13C NMR, UV) as well as their reduction potentials of these compounds have been determined to evaluate the utility potentials to chelating ligands for metal complexes or to synthetic precursors of viologen-type bipyridinium salts. The conjugation interaction throughout the three rings appears to be more significant in 3 and 4 than in 6. The formation of stable redical anions and dianions of 3 and 4 has been proved by cyclic voltammetry.
Correlation between Positron Annihilation and Gas Diffusion Properties of a Series of Polyimides
Authors: Tanaka Kazuhiro , Katsube Mikio , Okamoto Ken-ichi , Kita Hidetoshi , Sueoka Osamu , Ito Yasuo
Published: July 2006

The lifetime and the intensity of ortho-positronium (o-Ps), τ3 and I3, respectively, were measured for a series of polyimides prepared from 4,4′-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]diphthalic dianhydride. Average size of free space holes probed by o-Ps, υh,Ps, was evaluated from τ3 using an empirical equation. There was a clear correlation between logarithm of diffusion coefficients, , of CO2 and CH4 and υh,Ps for the polyimides. Large differences in among the polyimides having the same fractional free space, VF, were attributed to differences in υh,Ps. There was a fairly good correlation between log and (υh,PsI3)−1, suggesting that I3 is a measure of the concentration of free space holes which can accommodate o-Ps, at least for the polyimides with the similar chemical structure. Correlation between VF and υh,PsI3 was rather poor.
Solvent Extraction of Europium(III) with Benzoylacetone and Benzoyltrifluoroacetone into Carbon Tetrachloride in the Absence and Presence of Tetrabutylammonium Ions
Authors: Noro Junji , Sekine Tatsuya
Published: July 2006

The solvent extraction of europium(III) in 0.1 mol dm−3 sodium nitrate solutions with benzoylacetone (Hbza) or benzoyltrifluoroacetone (Hbfa) in carbon tetrachloride was measured in the absence and presence of tetrabutylammonium ions (tba+). Although extraction with Hbfa occurred at lower pH than with Hbza, the extraction measured as a function of the β-diketonate ion concentration in the aqueous phase was rather similar. It was also found that extraction with Hbfa was greatly enhanced by the addition of tba+, the effect, however, was negligible with Hbza. The data were analyzed from the stand point that the neutral metal chelate, Eu(bfa)3, was extacted into the organic phase and associated with ion-pairs of the reagents, bfa−tba+, in this phase. It was also found that though extraction of ion-pairs of bfa− tba+ occurred, that of bza−tba+ was negligible. Thus, the reason for the negligible extraction of the ternary complex, Eu (bza)4− tba+, was explained in terms of the negligible extraction of the bza−tba+, which might associate with Eu(bza)3 in the organic phase.
Preparation and Stereochemistry of the Mixed-Ligand Complex, Ammine(ethylenediamine)(ethylenediamine-N-acetato)cobalt(III)
Authors: Yasui Takaji , Ama Tomoharu , Kawaguchi Hiroshi , Okamoto Ken-ichi , Hidaka Jinsai
Published: July 2006

Four geometrical isomers for [Co(edma)(NH3)(en)]2+ (edma = ethylenediamine-N-acetate) were prepared for the first time; isomers with the facially chelated edma ligand were optically resolved. Geometrical structures were assigned on the basis of the absorption, 1H NMR, 13C NMR, and CD spectral data; the crystal structure of one of these isomers was determined by an X-ray diffraction method. The crystal is orthorhombic, space group P212121, a = 8.345(1), b = 21.054(2), c = 7.914(1) Å, V = 1390.6(3) Å3, Z = 4, and R = 0.047 for 1985 independent reflections [Fo>3σ(Fo)]. The cobalt atom is octahedrally surrounded by one ammine, the bidentate en, and the facially chelated edma ligands. The ammine ligand occupies the trans position of the secondary nitrogen atom in the edma, trans(Nc, NH3) geometry. This cation, which shows a positive CD sign at 519 nm, takes a ΛΔ configuration around the cobalt atom and an S configuration around the secondary nitrogen atom. The absolute configurations of the other optically active isomers with the facially chelated edma ligand were assigned based on the stereospecific deuteration for the methylene protons of the glycinate ring in the edma ligand in a basic D2O solution.
Comparison of IR-Transmission Method with the Conventional DTA Method (Kissinger Plot ) in the Crystallization Study of Iron Tellurite Glass
Authors: Nishida Tetsuaki , Inoue Satoru , Takashima Yoshimasa
Published: July 2006

IR-transmission spectra of 95TeO2·5Fe2O3 glass piece show a gradual decrease in the transmittance due to the crystallization initiating at the surface and spreading to the bulk. XRD, IR absorption spectra, and 57Fe-Mössbauer spectra show the formation of paratellurite (α-TeO2) and iron tellurite in the glass matrix. Johnson–Mehl–Avrami plot yields the activation energy (Ea) of 2.9 ± 0.3 eV for the crystallization when the crystallized fraction is approximated by the decreased fraction of IR-transmittance. The Ea is identical to the Te–O single bond energy (3.0 eV) obtained from the literature. Kissinger plot of DTA used for the crystallization in the bulk yields Ea of 2.3 eV. These results indicate that the crystallization proceeds in a two- or three-dimensional manner by the diffusion process both in the bulk and at the surface. Ar+-laser irradiation of 95TeO2·5Fe2O3 glass results in a decrease in the IR-transmittance, indicating the “optical memory” effect.
Atropisomerism in Doubly peri-Substituted 9-(2-Methylbenzyl)triptycene Derivatives, 8-Chloro- and 8-Bromo-1,4-dimethyl-9-(2-methylbenzyl)triptycenes
Authors: Yamamoto Gaku , Nemoto Takashi , Ohashi Yuji
Published: July 2006

The 13C dynamic NMR study revealed that 9-(2-methylbenzyl)triptycene has an energy barrier to gear rotation of 11.8 kcal mol−1 (1 cal = 4.184 J). Introduction of substituents at two of the peri-positions was expected to raise the barrier enough for atropisomerism to be realized in this system. Actually, two stable rotational isomers, ap and sc*(9S*), were separately isolated for 8-chloro- (7) and 8-bromo-1,4-dimethyl-9-(2-methylbenzyl)triptycene (8). Classical kinetic studies in toluene-d8 solutions revealed that the isomerization barriers (ΔG≠ at 350 K) are 26.4 and 27.2 kcal mol−1 for 7 and 8, respectively. Isomerization pathways were investigated by molecular mechanics calculations, which suggested that gear rotational pathway was favored. In either compound, the sc* (9S*) rotamer was found to thermally isomerize to the ap rotamer in the solid state. X-Ray crystallographic analysis of the rotameric crystals showed that the rotamers had different crystal structures and thus the crystal would be destroyed during the isomerization.
Rotational Isomerism and Atropisomerism in Acetal Derivatives of 1,2,3,4-Tetrafluorotriptycene-9-carbaldehyde
Authors: Yamamoto Gaku
Published: July 2006

In the ethylene acetal (2) of 1,2,3,4-tetrafluorotriptycene-9-carbaldehyde, equal amounts of the ap and ±sc rotamers exist in CDCl3 at equilibrium, while the equilibrium is strongly shifted to ±sc in the corresponding dimethyl and trimethylene acetals. Molecular mechanics calculations reveal the origin of this anomaly to reside in the conformation of the acetal moiety. Dynamic NMR studies show that the ap → ±sc barriers are too low for atropisomerism to be realized in these compounds (ΔG≠ ca. 21–22 kcal mol−1 (1 calth = 4.184 J)). However, taking advantage of the unusual equilibrium behavior, the two rotamers of 2 are separately isolated as crystals by selective crystallization of one rotamer from a solution of the equilibrated rotamer mixture.
Thermal Decomposition of Silver Amidotriphosphate Ag4P3O9NH2
Authors: Takenaka Atsushi , Motooka Itaru , Nariai Hiroyuki
Published: July 2006

Silver amidotriphosphate Ag4P3O9NH2, was heated at a rate of 5 K min−1 in a stream of dry air, humid air, or dry HCl. When heated to 245 °C in a stream of dry air, Ag4P3O9NH2 was decomposed mainly to oligophosphates with some phosphorus-nitrogen bonds. Condensation of Ag4P3O9NH2 by the action of HCl took place even at room temperature.
Asymmetric Synthesis of Benzoin by SmI2-Mediated Enantioselective Protonation
Authors: Takeuchi Seiji , Miyoshi Norikazu , Hirata Kenji , Hayashida Haruyoshi , Ohgo Yoshiaki
Published: July 2006

Samarium (Z)-1,2-diphenylethen-1,2-diolate, which is considered to be an intermediate of a SmI2-mediated reduction of benzil, was protonated enantioselectively by quinidine to afford (R)-benzoin in 91%ee. It was found that quenching the unreacted enediolate with oxygen was crucial to obtain high enantioselectivity. The configuration of the samarium enediolate was confirmed by isolating (Z)-O,O′-diacetyl-1,2-diphenylethen-1,2-diol.
Synthesis of Soluble Poly(thio-2,6-dimethyl-1,4-phenylene) by Oxidative Polymerization of Bis(3,5-dimethylphenyl) Disulfide
Authors: Jikei Mitsutoshi , Katoh Junya , Sato Naohiko , Yamamoto Kimihisa , Nishide Hiroyuki , Tsuchida Eishun
Published: July 2006

Poly(thio-2,6-dimethyl-1,4-phenylene) has been prepared by the oxidative polymerization of bis(3,5-dimethylphenyl) disulfide. The obtained polymer is amorphous and soluble in common organic solvents. The properties of the polymer are similar to those of poly(oxy-2,6-dimethyl-1,4-phenylene), rather than poly(thio-1,4-phenylene) (PPS). The polymer is obtained as a high molecular weight substance compared with other substituted or non-substituted PPS derivatives by the oxidative polymerization. The polymer containing a disulfide bond, whose structure was confirmed by the reduction of the polymer, acts as an initiator of radical polymerization.
Enantioselectivity in the Interaction of Calf Thymus DNA with Acridine Derivatives Having an Amino Ester or Amino Alcohol Substituent
Authors: Asakawa Masumi , Endo Ken , Kobayashi Kenji , Toi Hiroo , Aoyama Yasuhiro
Published: July 2006

Unless a bulky aromatic side chain is involved, acridine derivatives 1 and 2 having an amino ester or amino alcohol substituent bind to calf thymus DNA via intercalation. The binding constants evaluated by the Scatchard analysis of the hypochromicity data indicate that (1) the substituents introduced are rather inhibitory of the binding and (2) l-enantiomers are preferred than the d-enantiomers by a factor of KL/KD = 1.1–1.4, except for the case of aspartic and glutamic esters where the optical selectivity is very low or even reversed. The present enantioselectivity is discussed in terms of a local C2 chirality of the intercalation site, steric effects of the amino ester or amino alcohol substituents, and a possible conformation-controlling effect of the CO2CH3 or CH2OH group.
Reactions of 2-[(Phenylthio)methylene]tetralin-1-thione
Authors: Moriyama Satoshi , Motoki Shinichi
Published: July 2006

Hetero Diels–Alder reactions of 2-[(phenylthio)methylene]tetralin-1-thione (1) with methyl acrylate, methyl vinyl ketone, acrylonitrile, and other electron-poor dienophiles afford the corresponding cycloadducts (2), from which thiophenol is eliminated by the treatment with sodium alkoxide to give the corresponding 2H-thiopyran derivatives (3). The cycloadducts 2 with styrene and indene do not undergo elimination. The reactions of thioketone 1 with cycloalkenones give both the cycloadducts and the elimination products, even in the absence of a base. The reactions of 1 with acryloyl, crotonoyl, cinnamoyl, and 3-methyl-2-butenoyl chlorides give dienecarbothioic S-esters, in good yields, which are converted into stable dienecarbodithioic esters by the treatment with Lawesson’s reagent. In the reaction of 1 with methyl 2-bromoacrylate, elimination of sulfenyl bromide takes place to afford the elimination product 3.
EXAFS and X-Ray Diffraction Studies on the Structure of the Tetrathiocyanatocadmate(II) Complex in Dimethyl Sulfoxide
Authors: Ozutsumi Kazuhiko , Takamuku Toshiyuki , Ishiguro Shin-ichi , Ohtaki Hitoshi
Published: July 2006

The structure of the tetrathiocyanatocadmate(II) complex in dimethyl sulfoxide (DMSO) has been studied by the EXAFS (extended X-ray absorption fine structure) and solution X-ray diffraction methods. It has been revealed that the tetrathiocyanatocadmate(II) complex has a five-coordinate structure with an additional DMSO molecule. The structure in DMSO is different from that in water and N,N-dimethylformamide, in which no solvent molecule coordinates to the central metal ion. It has also been seen that the coordination mode of the thiocyanate ions in the tetrathiocyanatocadmate(II) complex changes depending on the source of thiocyanate ions due, probably, to different hydrogen bonding abilities of the N- and S-sites of the thiocyanate ion with the counter cations, i.e., the [Cd(NCS)3(SCN)(dmso)]2− and [Cd(NCS)4(dmso)]2− complexes are formed in solutions containing NH4SCN and (C2H5)4NSCN, respectively. The Cd–N, Cd–S, and Cd–O bond lengths within [Cd(NCS)3(SCN)(dmso)]2− are, respectively, 222(1), 262(1), and 234(1) pm, while the Cd–N and Cd–O bond lengths within [Cd(NCS)4(dmso)]2− are 223(1) and 239(2) pm, respectively.
Diastereoisomers of Platinum(II) Complexes with Chiral N-Substituted 1,2-Diamines. II. Structures of Dichloro[(S)-1-(2-amino-2-methylpropyl)amino-2-propanol]platinum(II)
Authors: Saito Reiko , Goto Masafumi , Hirose Junzo , Kidani Yoshinori
Published: July 2006

Square-planar complexes with the formula [PtCl2(S-Hp-Mepn)], where S-Hp-Mepn is (S)-1-(2-amino-2-methylpropyl)amino-2-propanol, CH3CH(OH)CH2NHCH2C(CH3)2NH2, were synthesized and separated into three types of crystals: small imbricate crystals (1), needles (2), and plates (3). 1H NMR spectroscopy has revealed that 1 and 2 are diastereoisomers each other but that 3 consists of both diastereoisomers in 1 : 1 composition. X-Ray crystallography has shown that the diastereoisomer 2 has the absolute configuration of R about the nitrogen atom of secondary amine and 3 is a quasi-racemic compound of S(N) and R(N) isomers: 2; orthorhombic, space group P212121 with a = 10.447(1), b = 13.017(2), c = 8.764(2) Å, R = 0.043, Rw = 0.052: 3; monoclinic, space group C 2 with a = 21.530(1), b = 11.019(2), c = 13.491(5) Å, β = 125.73(1)°, R = 0.042, Rw = 0.054. But the conformations of R(N)-isomers in 2 and 3 were different. The analysis of the CD and 1H NMR spectra of 1 and 2 shows that 1 has the absolute configuration of S about the secondary amine site. For both isomers, the major conformers in aqueous solution are those with equatorially substituted N-hydroxypropyl group and are different from those found in crystals where the packing force participates.
Synthesis of a Polycyclic π-Conjugated System Containing an Azulene Unit by the Flash Vacuum Pyrolytic Method. II. Synthesis and Paratropic Properties of 3H-Cyclopent[a]azulen-3-one and Its Methyl Derivatives
Authors: Kitamori Yoichiro , Yasunami Masafumi , Hioki Takanori , Kikuchi Ikue , Takase Kahei
Published: July 2006

3H-Cyclopent[a]azulen-3-one and two methyl derivalives, which have a new tricyclic π-conjugated system, were synthesized starting from 9-methoxycarbonyl-1,2-dihydro-3H-cyclopent[a]azulen-3-one by the application of flash vacuum pyrolysis in the final step. All proton signals of these compounds were observed at higher fields than those of the referenced 1,2-dihydro compound, but there are no significant differences between the carbon magnetic resonances of 3H-cyclopent[a]azulen-3-ones and the reference compound. These high field shifts on 1H NMR were appreciated in terms of an induced paramagnetic ring current caused by the contribution of a 12-π electron system in the periphery of this molecule. 3H-cyclopent[a]azulen-3-one was stable in the crystalline state, but gradually changed in solution to a hexacyclic compound by decarbonylative dimerization, while the 2-methyl derivative was very stable both in the crystalline state and in solution. Although the reaction of 3H-cyclopent[a]azulen-3-one with cyclopentadiene immediately gave a [4+2] cycloaddition product, the reaction with dimethyl acetylenedicarboxylate gave no products. These chemical behaviors are consistent with the results of Hückel molecular orbital calculations.
Syntheses of Azobenzene Derivatives Having Fluoroalkyl Chain and Their Monomolecular Film Formation at the Air/Water Interface
Authors: Yoshino Norio , Kitamura Mitsuharu , Seto Tsuyoshi , Shibata Yasuhiro , Abe Masahiko , Ogino Keizo
Published: July 2006

The compounds, 4-(nonafluorobutyl)aniline, 4-(tridecafluorohexyl)aniline, and 4-(heptadecafluorooctyl)aniline were prepared by the reaction of corresponding perfluoroalkyl iodide with 4-iodoaniline in the presence of copper bronze. Six azobenzene derivatives (4-(4-fluorophenylazo)phenol, F(C6H4)N=N(C6H4)OH (1) (C6H4 = p-phenylene), 4-(4-trifluoromethylphenylazo)phenol, CF3(C6H4)N=N(C6H4)OH (2), 4-(4-heptafluoropropylphenylazo)phenol, C3F7(C6H4)N=N(C6H4)OH (3), 4-(4-nonafluorobutylphenylazo)phenol, C4F9(C6H4)N=N-(C6H4)OH (4), 4-(4-tridecafluorohexylphenylazo)phenol, C6F13(C6H4)N=N(C6H4)OH (5), and 4-(4-heptadecafluorooctylphenylazo)phenol, C8F17(C6H4)N=N(C6H4)OH (6)) were prepared by the usual diazo coupling reactions using 4-(perfluoroalkyl)aniline and phenol. The monomolecular film formations of the azobenzene derivatives at the air/water interface were investigated by surface pressure measurements to be dependent on the fluoroalkyl chain length (n). The compounds 5 (n = 6) and 6 (n = 8) formed stable monomolecular films at the air/water interface.
Topochemical Studies. XV. Structure of Triclinic Form of the Photodimer of Cinnamamide
Authors: Iwamoto Tetsuyuki , Kashino Setsuo
Published: July 2006

New polymorph of the photodimer of cinnamamide has been found: 2,4-Diphenyl-1,3-cyclobutanedicarboxamide, C18H18N2O2, Mr = 294.16, mp = 553–555 K, triclinic, , a = 8.756(1), b = 16.969(1), c = 5.2499(3) Å, α = 93.104(6), β = 106.514(7), γ = 97.035(8)°, V = 738.9(1) Å3, Z = 2, Dm = 1.32(1), Dx = 1.323 Mg m−3, Cu Kα (λ = 1.54178 Å), μ = 0.71 mm−1, F(000) = 312, T = 295 K, R = 0.045 for 2138 unique reflections with |F0| larger than σ(F0). The crystal structure has close relationship with that of cinnamamide. The structure is also discussed in comparison with that of the monoclinic form of the photodimer.
An Isomeric Series of Thiophene-Fused Tetracyanoquinodimethanes. II. The Crystal and Molecular Structures
Authors: Iwasaki Fujiko , Toyoda Nobuhiko , Hirota Masamichi , Yamazaki Norimasa , Yasui Masanori , Kobayashi Keiji
Published: July 2006

The crystal structures of three isomeric thiophene-fused TCNQs, 4,8-bis(dicyanomethylene)-4,8-dihydrobenzo[1,2-b : 4,5-b′]dithiophene (1), [1,2-b : 5,4-b′] isomer (2), and [1,2-b : 4,5-c′] isomer (3) have been determined by the X-ray method. The crystals of 1, 2, and 3 are an isostructure of the monoclinic system with the space group of P21/n. For 1, a = 16.588(3), b = 7.222(5), c = 11.353(3) Å, β = 89.88(2)°, V = 1360.1(10) Å3, Z = 4, Dx = 1.545 Mg m−3. For 2a = 16.594(4), b = 7.232(2), c = 11.433(2) Å, β = 91.05(2)°, V = 1371.8(5) Å3, Dx = 1.532 Mg m−3. For 3a = 16.738(2), b = 7.342(3), c = 10.922(3) Å, β = 92.98(2)°, V = 1340.4(7) Å3, Dx = 1.568 Mg m−3. These crystals show an orientational disorder with an approximate molecular symmetry of mm. The occupancy factors are 0.834 : 0.166, 0.709 : 0.291, and 0.5 : 0.1 : 0.15 : 0.25 for 1, 2, and 3, respectively. The final R values are 0.065, 0.070, and 0.096 for 2308, 2410, and 1566 observed reflections for 1, 2, and 3, respectively. In the crystals molecules form a sheet-like network perpendicular to the b axis, with short intermolecular S···N distances (3.047 and 3.086 Å for 1 and 3.076 Å for 2). The internetwork distances between S atoms are significantly shorter than the van der Waals contact: 3.451 and 3.461 Å for 1 and 2, respectively. Each molecule has a butterfly shape. Two dicyanomethylene groups are bent from the quinonoid ring to the same side and two thiophene rings are bent to the opposite side of the dicyanomethylene groups.
An Isomeric Series of Thiophene-Fused Tetracyanoquinodimethanes. III. Crystal Structures of Charge-Transfer Complexes with TTF
Authors: Iwasaki Fujiko , Hironaka Shinji , Yamazaki Norimasa , Kobayashi Keiji
Published: July 2006

The crystal structures of the charge-transfer complexes of two isomeric thiophene-fused TCNQs, 4,8-bis(dicyanomethylene)-4,8-dihydrobenzo[1,2-b : 4,5-b′]dithiophene (1), and [1,2-b : 4,5-c′] isomer (3) with tetrathiafulvalene (TTF) have been determined by the X-ray method. For 1–TTF, triclinic, , a = 10.458(2), b = 9.852(2), c = 11.292(8) Å, α = 92.60(7), β = 113.64(6), γ = 97.38(6)°, V = 1051(2) Å3, Z = 2, Dx = 1.646 Mg m−3. For 3–TTF, triclinic, , a = 9.059(2), b = 8.459(2), c = 8.850(2) Å, α = 103.36(2), β = 115.76(2), γ = 106.30(2)°, V = 535.1(3) Å3, Z = 1, Dx = 1.616 Mg m−3. The final R values are 0.079 for 3437 observed reflections and 0.048 for 1937 observed reflections for 1–TTF and 3–TTF, respectively. The crystal structure of 1–TTF complex is composed of TTF pairs and TCNQ pairs. These pairs stack alternately with each other. The mean distances between molecular planes are: 3.62 Å for TTF–TTF, 3.49 Å for 1–1 and 3.36 Å for 1–TTF. In the crystals of 3–TTF the molecules form mixed stacks with the separation of 3.59 Å. The molecular geometry of TTF in the 1–TTF complex shows a TTF+ character, while that in 3–TTF shows a neutral type.
Transfer of Electronic Excitation Energy from 2,2-Diphenylethanol to 2,6-Diphenylpyridine in Solvents of Different Viscosity
Authors: Jana Pallabi , Mallik Gautam Kumar , Ganguly Tapan , Banerjee Sukhendu Bikash
Published: July 2006

Measurement of emission spectra indicates that in diluted solution of 2,2-diphenylethanol (DPE)–2,6-diphenylpyridine (DPP) system in solvents of different viscosity, the rate parameters kxy associated with nonradiative energy transfer from donor X (DPE) to acceptor Y (DPP) decrease with increasing viscosity of the medium. Further kxy values are higher than diffusion controlled rates kd. The Förster critical transfer distance R0 is much greater than the sum of the radii of the donor and acceptor, rx+ry. The observations seemingly indicate that energy-transfer from donor DPE to acceptor DPP mainly occurs by coulombic interaction over the dipole–dipole interaction distance which exceeds the molecular dimensions. In the DPE–DPP system, there is no evidence of external quenching.