bluuebunny/crossref_metadata_2025_split huggingface dataset:
Samarium(II)‐induced coupling of acid chlorides with allylic halides
Authors: Araki Shuki , Hatano Masahiro , Ito Hirokazu , Butsugan Yasuo 
Published: January 2005

AbstractSamarium(II)‐induced coupling of acid chlorides with allylic halides gave diallylated tertiary alcohols. Monoallylated allylic ketones could not be obtained.
Organic lead compounds in vehicle exhaust
Authors: Hewitt C Nicholas , Rashed M B 
Published: January 2005

AbstractSpecies‐specific measurements of the five tetraalkyllead compounds used in gasoline and their intermediate decomposition products, the tri‐ and di‐alkyllead species, have been made in vehicle exhaust fumes. Under normal engine running conditions 0.3–3% of the lead emitted in exhaust is as an organic compound, but cold, choked engines emit proportionally much larger amounts of alkyllead. Alkyllead is emitted in both the gas and the aerosol phases.
Preparation of di(n‐butyl) tin and di(n‐octyl) tin dihalides by the direct synthesis method
Authors: Chee Ong Ghee , Das V G Kumar 
Published: January 2005

AbstractThe direct synthesis of the two industrially important organotin intermediates, di(n‐butyl)tin and di(n‐octyl)tin dihalides, has been investigated by reacting the appropriate alkyl halide with metallic tin undervarying conditions. Observations were made on the influences of temperature, pressure, reaction time, nature of the tin metal, organic halide/tin reactant ratios and the presence of catalysts on the extent of tin conversion and yields of the organotin products. The efficacy of the onium halides, notably n‐Bu4NI, Me3SI and Ph3MeAsI, either singly or in binary combinations with iodine or inorganic iodine compounds, in catalysing the synthesis of the above dialkyltins as well as higher di(n‐alkyl)tin analogues is described.
Synthesis and psychotropic properties of furyl‐ and thienyl‐germatranes
Authors: Lukevics Edmunds , Ignatovich Lubov , Porsiurova Natalia , Ǧērmane Skaidrīte 
Published: January 2005

AbstractTrihalogermyl‐furans and ‐thiophenes magnified image were prepared by inserting germanium dibromide (GeBr2) generated from the dibromogermane(II) dioxanate complex into the carbon‐halogen bond of halo‐furans and ‐thiophenes. Their ethanolysis and transesterification by triethanolamine yielded the germatranes magnified image which were subjected to psychotropic activity assays. The psychotropic properties of germatranes were found to depend on the type of the heterocycle and on the position of the germatrane moiety.
Speciation of butyltin compounds in oyster samples
Authors: Rapsomanikis S. , Harrison Roy M 
Published: January 2005

AbstractExperimental instrumentation for the speciation of butyltin compounds by hydride generation and gas chromatography‐quartz furnace atomic absorption spectrometry is described. Evaluation of a number of extraction methods revealed that simple acid leaching of oyster samples gave adequate recoveries. The levels of each butyltin species in oyster flesh and gill are reported together with the tentative identification of a mixed methylbutyltin compound.
Correlation of molecular total surface area with organotin toxicity for biological and physicochemical applications
Authors: Eng G , Tierney E J , Bellama J M , Brinckman F E 
Published: January 2005

AbstractThere exists a high correlation between molecular total surface area (TSA) values and diorganotin toxicity towards several distinct types of organisms. This correlation was found for N2a neuroblastoma cells, 3T3 fibroblasts, Daphnia magna Rhithropanopeus harrisii and Ankistrodesmus falcatus. In the case of Rhithropanopeus harrisii, a high correlation was also found between TSA and toxicity for triorganotins as well. This study suggests that the relationship between TSA and toxicity is a function of the hydrophobicity of the organotin compounds rather than electronic or steric effects.
The lifetimes of organosulphur compounds in the troposphere
Authors: Hewitt C Nicholas , Davison Brian M 
Published: January 2005

AbstractDimethyl sulphide and other reduced sulphur compounds, produced by marine biogenic activity and other processes, play a significant role in the global biogeochemical cycling of the element. The rates of their reactions with atmospheric oxidants are reviewed and their lifetimes in the troposphere due to the various reactions are computed. Sufficient data are available on the tropospheric abundance of the hydroxyl radical (OH) and on the rates of its reactions with the sulphur compounds for reasonable estimates to be made of the sulphur lifetimes with respect to OH. Summertime lifetimes of 14–87 h for (CH3)2S are computed at different latitudes. In the case of the tropospheric concentrations of the nitrate radical (NO3), few data are available. There is a similar paucity of data on its rates of reactions with the sulphur compounds, and so large uncertainties exist in the computed lifetimes. These are, in any case, much longer than those due to OH. The possibility exists that iodine photochemistry, producing iodoxyl (IO) radicals, may efficiently oxidize the reduced sulphur and other organic compounds in the marine troposphere leading to lifetimes of the order of hours. Few data exist on the rates or mechanisms of these reactions and these are identified as representing the greatest uncertainties in the estimates of organosulphur lifetimes in the troposphere.
A 119Sn Mössbauer spectroscopic study on complexes of di‐and tri‐organotin(IV) moieties with 2‐mercaptoethanesulfonates, in the solid state and in aqueous solution
Authors: Barbieri Renato , Silvestri Arturo , Huber Friedo 
Published: January 2005

AbstractThe configuration of the bonding environment of tin in the complexes [R2Sn(SCH2CH2SO3)2]2− (R = Me, Ph) and [Me3Sn(SCH2CH2SO3)]− has been determined to be tetrahedral both in the solid state and in aqueous solution (for the methyl derivatives). The coordination number of tin increases to five in aqueous solutions for the Me2Sn(IV) complexes in Hepes buffer (N‐2‐hydroxyethylpiperazine‐N′‐2‐ethanesulfonic acid; at least in fivefold excess, at pH 7.4) due to coordination by the tertiary amino nitrogen atom. No effect is detected due to the surfactant 2‐hydroxypropylcellulose concerning both coordination to tin and influence on the Mössbauer parameters. The stoichiometry of mixed complex formation in aqueous solution of Me2Sn(IV), 2‐mercaptoethanesulfonate and Hepes is 1:2:1, according to a procedure of ‘Mössbauer titration’. All complexes in aqueous solution undergo slow lysis of the tin‐sulfur bonds. Structural assignments have been generally effected on the basis of the magnitude of experimental values of Mössbauer nuclear quadrupole splittings, measured at 77 K for both solid and frozen aqueous absorbers, and comparison with data calculated by the point‐charge model approach.
Gallium‐induced Barbier coupling of carbonyl compounds with allyl iodide
Authors: Araki Shuki , Ito Hirokazu , Butsugan Yasuo 
Published: January 2005

AbstractGallium metal readily prompted the allylation of aldehydes and ketones with allyl iodide. α, β‐Unsaturated carbonyl compounds underwent only 1,2‐addition.
The synthesis of heteronuclear transition‐metal clusters derived from methylidyne tricobalt cluster precursors: The reaction of Mn(CO) with (μ3‐CCl)Co3(CO)7(μ‐dppm). The crystal and molecular structure of (μ3‐CH)Co2Mn(CO)8(μ‐dppm), a methylidyne cluster containing a seven‐coordinate manganese atom
Authors: Duffy D Neil , Kassis Maram M , Rae A David 
Published: January 2005

AbstractThe reaction of manganese pentacarbonyl anion with chloromethylidyne tricobaltnonacarbonyl, (μ3‐CCl)Co3(CO)9, leads to reduction of the cluster with formation of Mn2(CO)10 and Co(CO), whilst reaction of Mn(CO) with the bis(diphenylphosphino)methane (dppm)‐stabilised cluster (μ3‐CCl)Co3(CO)7(μ‐dppm) leads to the formation of (μ3‐CH)Co2Mn(CO)8(μ‐dppm), 1. The unique feature of the structure of 1 is the incorporation of a seven‐coordinate manganese atom into the metal triangle.
Ambidentate coordination of the tripyridyl ligands 2,2′:6′,2″‐terpyridyl, tris(2‐pyridyl)‐amine, tris(2‐pyridyl)methane and tris(2‐pyridyl)phosphine to carbonylrhenium centres: Structural and spectroscopic studies
Authors: Anderson Peter A , Keene F Richard , Horn Ernst , Tiekink Edward R T 
Published: January 2005

AbstractThe reactions of [Re(CO)5Cl] with the ligands tpy (2,2′:6′,2″‐terpyridine), py3N {tris(2‐pyridyl)‐amine}, py3CH {tris(2‐pyridyl)methane}, and py3P {tris(2‐pyridyl)phosphine} in toluene solution realize compounds with the general formulation [Re(ligand)(CO)3Cl] in which the tripyridyl ligands are bidentate. X‐ray structural determinations of fac‐[Re(typ)(CO)3Cl].H2O and fac‐[Re(py3N)(CO)3Cl] confirm these assignments. [Re(tpy)(CO)3Cl].H2O (C18H13ClN3O4Re) is monoclinic, space group P21/n, with cell dimensions a = 7.432(2) Å, b = 17.016(4) Å, c = 14.466(2) Å, β = 93.51(2)°, and Z = 4; full‐matrix least‐squares refinement on 2435 reflections with I ⩾ 2.5σ(I) converged to a final R = 0.028 and Rw = 0.029. [Re(py3N)(CO)3Cl] (C18H12ClN4O3Re) is triclinic, space group P1 with cell dimensions a = 13.761(2) Å, b = 14.636(6)Å, c = 11.110(2) Å, α = 110.70(2)°, β = 102.45(2)°, γ = 107.48(2)°, and Z = 4; full‐matrix least‐squares refinement on 3459 reflections with I ⩾ 2.5σ(I) converged to a final R = 0.038 and Rw = 0.039. If the synthetic procedure is undertaken under irradiation by visible light, for the ligand py3N a species [Re(py3N)(CO)2Cl] (characterized by infrared spectroscopy and conductance measurements) is also formed, in which the ligand py3N is tridentate. No analogous tridentate species is formed with the ligands tpy or py3P, although there is evidence that it also forms for py3CH.
In vitro antitumour activities of a novel 2:3 condensation product of salicylaldoxime with di‐n‐butyltin(IV) oxide
Authors: Bouǎlam Mohammed , Biesemans Monique , Meunier‐Piret Jacqueline , Willem Rudolph , Gielen Marcel 
Published: January 2005

AbstractThe antitumor activities of three novel condensation products of salicylaldoxime with di‐n‐butyltin(IV) oxide (compound 1), di‐t‐butyltin oxide (compound 2) and diphenyltin oxide (compound 3) are presented. Against MCF‐7, a human mammary tumor cell line, compounds 1 and 2 are characterized by inhibition doses ID50 in vitro of 67 and 49 ng cm−3 respectively, whereas cis‐platin, an antitumor drug used clinically, has an ID50 of 850 ng cm−3. Against WiDr, a colon carcinoma, they also score better than cis‐platin: 215 and 121 ng cm−3 versus 624 ng cm−3. In contrast, the diphenyltin compound, 3, is inactive against both tumor cell lines.The results of a pre‐screening performed on compound 1 by the National Cancer Institute (NCI) on a panel of 60 human tumor cell lines show that two of the selectivity parameters calculated by the NCI for that compound are statistically significant, namely DG150 (51.9>50) and MGDH (80.1>75). One is almost satisfactory (DH = 72.4 = ca75). The other two, DTGI (40.0<50) and DLC50 (16.7<50) are not. (Abbreviations are explained in the text and in Gielen, M. and Willem, R. Anticancer Res., 1992, in press).
Bioaccumulation of arsenic and its fate in a freshwater food chain
Authors: Maeda Shigeru , Ohki Akira , Kusadome Katsuhiro , Kuroiwa Takayoshi , Yoshifuku Isami , Naka Kensuke 
Published: January 2005

AbstractAccumulation, biomethylation and excretion of arsenic by an autotrophic freshwater alga, and the transport and transformation of the arsenic in the freshwater food chain [alga (autotroph)‐moina (planktonic grazer) or shrimp (herbivore)‐guppy (carnivore)] were investigated.These experimental results lead to the conclusion that total arsenic concentrations in organisms after accumulation from foods decreased one order of magnitude per elevation of the trophic level and biomethylation of the arsenic increased successively with an elevation in the trophic level. Predominant methylated arsenic species in moina and guppy were dimethyl‐ and trimethyl‐arsenic compounds, respectively. Shrimp accumulated dimethyl‐ and trimethyl‐arsenic compounds in nearly equivalent quantities. No or little monomethylarsenic compound was detected either in herbivores or carnivores.
The anti‐neoplastic activity of ethylamine‐carboxyborane and triphenylphosphine‐carboxyborane in L‐1210 lymphoid leukemia cells
Authors: Hall Iris H , Hall E Stacy , Chi L K , Iii M C Miller , Bastow Ken F , Sood A , Spielvogel B F 
Published: January 2005

AbstractStudies on the mode of action of two boroncontaining anti‐neoplastic agents, ethylamine‐carboxyborane and triphenylphosphine‐carboxyborane, are reported. The major site of inhibition was in the pyrimidine de nove synthetic pathway at orotidine monophosphate decarboxylase activity. Additional sites which may facilitate the inhibition of cell growth were IMP dehydrogenase, thymidine kinase, TMP kinase and TDP kinase, m‐RNA, r‐RNA and t‐RNA polymerase activities as well as topoisomerase II activity. The reduction in enzyme activities led to sufficient reduction of d(NTP) levels to suppress DNA synthesis and cell growth. DNA strand scission was evident in the presence of drug. Multiple modes of action are common with amine‐carboxyboranes. Acute toxicity studies in mice showed that both agents were safe in their therapeutic range based on organ weights, histological tissue sections, clinical chemistry values and hematopoietic parameters.
Synthesis and psychotropic properties of 1‐triorganylsiloxy‐ and 1‐triorganylgermoxy‐germatranes
Authors: Lukevics Edmunds , Ignatovich Lubov , Shilina Natalia , Ǧērmane Skaidrīte 
Published: January 2005

AbstractTriorganylsiloxy‐ and triorganylgermoxy‐germatranes have been prepared by the interaction of the easily available 1‐hydroxygermatrane with various hetaryl‐silanes and ‐germanes. The compounds were of the general structure: magnified image

M = Si; X = S, CH = CH (viz. phenyl); n = 0,1,2
M = Ge; X = CH = CH (viz. phenyl); n = 0
All siloxy‐ and germoxy‐germatranes obtained were subjected to psychotropic assays. Some of phenylsiloxygermatranes are effective for memory enhancement (inhibition of retrogradal amnesia by triphenylsiloxygermatrane was 80%).
Subchronic oral toxicity (six months) of carboxyethylgermanium sesquioxide [(HOOCCH2CH2Ge)2O3]n in rats
Authors: Anger F , Anger J P , Guillou L , Papillon A , Janson C , Sublet Y 
Published: January 2005

AbstractAfter briefly renewing toxicological data on germanium compounds, the authors report on the subchronic oral toxicity of carboxyethylgermanium sesquioxide in rats. During six months, male and female animals received 1 g kg−1. day−1. No particular toxic symptoms, and no behaviour problems except a small decrease of body weight in male rats, at the end of the six‐month experimentation period, were observed. A significant decrease of erythropoiesis and some significant changes in leucocyte ratios were demonstrated. The main marked effect was a moderate renal dysfunction characterized by a tubular disease with the presence of cylinders, swelling of tubulus cells and flocculus deposits. Germanium urinary excretion was constant and linked to the received dose. Six months later, no preferential accumulation in organs was evident.
GC FPD method for the simultaneous speciation of butyltin and phenyltin compounds in waters
Authors: Gomez‐Ariza J L , Morales E , Ruiz‐Benitez M 
Published: January 2005

AbstractA method is described for the simultaneous determination of nanogram amounts of mono‐, di‐ and tri‐butyltin compounds in water. The procedure is based on the conversion of tin compounds to volatile species by Grignard pentylation and analysis using GC with flame photometric detection (GC FPD). The ionic compounds are extracted from diluted acidified (HBr) aqueous solutions by using a pentane‐tropolone solution. The extracted organotin compounds are pentylated by a Grignard reagent and purified on a Fluorisil column before analysis by GC FPD. The detection limits are 20 ng dm−3 for butyltin compounds and 50 ng dm−3 for phenyltin compounds. Recoveries from spiking experiments in tap‐water and natural seawater matrices, in which no organotin compounds were detected, were greater than 90% for most of the alkyltin compounds.
Characterization of organic arsenic compounds in bivalves
Authors: Shibata Yasuyuki , Morita Masatoshi 
Published: January 2005

AbstractWater‐soluble arsenic compounds were extracted with methanol/water (1:1, v/v) from various species of bivalves and also from certified reference materials (NIES No. 6, mussel tissue, and NBS 1566, oyster tissue). The extracts were analyzed with a high‐performance liquid chromatograph combined with an inductively coupled argon plasma mass spectrometer serving as an arsenic‐specific detector. A certified reference material (NIES No. 6) was used to check the reproducibility of the analysis. The relative standard deviations (RSDs) of the peak area of major arsenic compounds among repeated measurements (n = 6) on the same extrct were less than 3.3%, indicating good reproducibility of the technique. The RSDs of some peaks among measurements of independent extracts, on the other hand, were more than 10%, possibly reflecting the heterogeneity of the sample in terms of the chemical species under the present experimental conditions. In many of the samples analyzed in the present study, two arsenic‐containing ribofuranosides were detected in addition to arsenobetaine. A compound bearing a glycerophosphoryl glycerol moiety was dominant in such cases. Interestingly, a bivalve living in an estuary (Corbicula japonica) did not contain a detectable amount of arsenobetaine though it had arsenic‐containing ribofuranosides. The distribution of arsenic species in the various parts of a clam (Meretrix lusoria) and a mussel (Mytilus coruscum) was also analyzed.
Acute toxicity and metabolism of arsenocholine in mice
Authors: Kaise Toshikazu , Horiguchi Yoshiya , Fukui Shozo , Shiomi Kazuo , Chino Makoto , Kikuchi Takeaki 
Published: January 2005

AbstractThe acute toxicity of arsenocholine was examined in mice by oral administration and intravenous injection. The LD50 values of arsenocholine were 6.5 g kg−1 for oral administration and 187 mg kg−1 for oral administration and 187 mg kg−1 for intravenous injection. Decreases of respiration and spontaneous motility were observed in the mice dosed orally at 12 g kg−1. The animals exhibited ataxia and finally showed paralysis of the hind legs within 20 min of administration. When arsenocholine was administered orally to mice at 5 or 50 mg As kg−1, the greater part of the arsenic administered was recovered in urine within 96 h. The metabolite of arsenocholine in urine was identified as arsenobetaine by high‐performance liquid chromatography‐inductively coupled plasma emission spectrometry (HPLC ICP) and fast atom bombardment mass spectrometry (FAB MS). These results suggested that the major part of orally administered arsenocholine was absorbed from the gastrointestinal tract in mice and then rapidly excreted in urine with biotransformation.
Formation of arsenobetaine from arsenocholine by micro‐organisms occurring in sediments
Authors: Hanaoka Ken'Ichi , Satow Takeharu , Tagawa Shoji , Kaise Toshikazu 
Published: January 2005

AbstractAs one of the experiments to pursue marine circulation of arsenic, we studied microbiological conversion of arsenocholine to arsenobetaine, because arsenocholine may be a precursor of arsenobetaine in these ecosystems. Two culture media, 1/5 ZoBell 2216E and an aqueous solution of inorganic salts, were used in this in vitro study. To each medium (25 cm3) were added synthetic arsenocholine (0.2%) and about 1 g of the sediment, and they were aerobically incubated at 25°C in the dark. These conversion experiments were performed in May and July 1990. In both seasons, two or three metabolites were derived in each mixture. These metabolites were purified using cation‐exchange chromatography. Their structures were confirmed as arsenobetaine, trimethylarsine oxide and dimethylarsinic acid by high‐performance liquid chromatography, thin‐layer chromatography, FAB mass spectrometry and a combination of gas‐chromatographic separation with hydride generation followed by a cold‐trap technique and selected‐ion monitoring mass spectrometric analysis. From this and other evidence it is concluded that, in the arsenic cycle in these marine ecosystems, as recently postulated by us, the pathway arsenocholine → arsenobetaine → trimethylarsine oxide → dimethylarsinic acid → methanearsonic acid → inorganic arsenic can be carried out by micro‐organisms alone.
Arsenic distribution in rats fed a Hijiki diet
Authors: Katayama Masayuki , Sugawa‐Katayama Yohko , Tamura Tomoko 
Published: January 2005

AbstractVery large doses of sodium arsenate (Na2HAsO4), 14 mg As kg−1 of body weight, were administered to Sprague‐Dawley male rats (body weight 300 g) fed a 5% Hijiki diet by stomach tube twice within two days. After 24 h, the rats were sacrificed and various organs were dried for subsequent neutron activation analysis. The distribution of arsenic (As) in selected organs was determined by neutron activation analysis. The highest concentration of As was found in blood cells with a rather high concentration in the liver and heart. As the control, rats which were fed on a 5% cellulose diet were used. Control rats which were administered arsenate showed that the arsenic distribution and the concentration in their organs were similar to those on the 5% Hijiki diet. Even the blood cells of the controls without any arsenic administration were found to contain a small amount of arsenic.
Uptake and excretion of total inorganic arsenic by the freshwater alga Chlorella vulgaris
Authors: Maeda Shigeru , Kusadome Katsuhiro , Arima Hiroyuki , Ohki Akira , Naka Kensuke 
Published: January 2005

AbstractArsenic‐tolerant freshwater alga Chlorella vulgaris which had been collected from an arsenicpolluted environment were tested for uptake and excretion of inorganic arsenic.Approximately half the quantity of arsenic taken up by C. vulgaris was estimated to be adhered to the extraneous coat (10 wt %) of the cell. The remainder was bioaccumulated by the cell. Both adhered and accumulated arsenic concentrations increased with an increase in arsenic(V) concentration of the aqueous phase.Arsenic(V) accumulation was affected by the growth phse: arsenic was most actively accumulated when the cell was exposed to arsenic during the early exponential phase and then accumulation decreased with an increase in culture time exposed to arsenic.The alga grew well in the modified Detmer (MD) medium containing 1 mg As(III) dm−3 and the growth curve was approximated by a ‘logistic equation’. Arsenic(III) was accumulated up to the second day of the culture time and arsenic(III) accumulation decreased with an increase in the culture time after that.Arsenic accumulation was also largely affected by various nutrients, especially by managanese, iron and phosphorus compounds. A modified MD medium with the three nutrients was proposed for the purpose of effective removal of arsenic from the aqueous phase.Using radioactive arsenate (Na2H74AsO4), the arsenic accumulated was found to be readily excreted under conditions which were unfavourable for the multiplication of C. vulgaris.
2,5‐Dimethylthiophene coordination to three metal centers in the complexes (η4, S‐μ3‐2,5‐Me2T)(IrCp*) [M(CO)2Cp]2 where MMo or W
Authors: Chen Jiabi , Angelici Robert J 
Published: January 2005

AbstractThe 2,5‐dimethylthiophene (2,5‐Me2T) ligand in the isomers Cp*Ir(η4‐2,5‐Me2T) (1) and Cp*Ir(C,S‐2,5‐Me2T) (2) is activated to react with the dimers Cp(CO)2MM(CO)2Cp[MMo (3), W (4)] to give complexes (5,6) in which the thiophene is coordinated to three metals. Oxidation of 5 with Cp2Fe+ removes magnified image the Mo dimer to give Cp*Ir(η5‐2,5‐Me2T)2+. Reaction of 5 with CO displaces the Mo as [CpMo(CO)3]2 to give Cp*Ir(CO)(C,S‐2,5‐Me2T) (7). Ultraviolet photolysis of 1 provides a convenient route to the ring‐opened isomer 2. Despite the remarkable nature of the thiophene coordination in 5 and 6, its reactivity does not suggest new pathways that would lead to the hydrodesulfurization of thiophenes.