bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heterocyclic synthesis containing bridgehead nitrogen atom: Synthesis of 3‐[(2H)‐2‐oxobenzo[b]pyran‐3‐yl]‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazine and thiazole derivatives
Authors: Raslan M. A. , Khalil M. A. 
Published: March 2003

AbstractThe reaction of 2H‐2‐oxobenzo[b]pyran‐3‐hydrazide (2) with carbon disulfide in basic DMF afforded potassium thiocarbamate 3, which readily underwent heterocyclization upon its reaction with hydrazine and/or phenacyl bromide to yield 1,2,4‐tiazole (4) and thiazole 7 derivatives, respectively. Condensation of 4 with substituted phenacyl bromide and/or chloranil gave 1,2,4‐triazole[3,4‐b]thiadiazine (5a,b) and 3,10‐bis‐[2H‐2‐oxobenzo[b]pyran‐3‐yl]‐6,13‐dichloro‐bis‐1,2,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazino[5′,6′‐b:5′,6′‐e]cyclohexa‐1,4‐diene (6), respectively. Cyclization of thiosemicarbazide 10 by refluxing it in sodium hydroxide and/or phosphoryl chloride afforded triazole 13 and thiadiazole 15 derivatives, respectively. Also, 10 reacted with phenacyl bromide in the presence of anhydrous sodium acetate to give the oxothiazolidine derivative 17. The structure of the synthesized compounds were confirmed by elemental analyses, IR, 1H NMR, and mass spectra. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:114–120, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10109
Syntheses of cyanoselenoamides and diselenoamides: Conversion into selenazoles and selenazines
Authors: Koketsu Mamoru , Takenaka Yuichi , Ishihara Hideharu 
Published: March 2003

AbstractReactions of dicyano compounds with a potassium selenocarboxylate afforded the corresponding cyanoselenoamides and diselenoamides in good yields of experimentally determined ratios. The obtained cyanoselenoamides were allowed to react with potassium selenocarboxylate, again to afford the corresponding diselenoamides in higher yields. The cyanoselenoamides and diselenoamides were investigated as substrates for preparations of selenazoles and selenazines. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:106–110, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10111
Complexes of diethyl‐2‐amino‐2‐oxoethylphosphonate with lanthanide nitrates
Authors: Petrova Jordanka , Momchilova Snezana , Vassilev Nikolay G. , Haupt Erhard T. K. 
Published: March 2003

AbstractLanthanide complexes LnL2(NO3)3 3a–f are obtained where Ln is La, Ce, Sm, Eu, Er, and Yb and L is the diethyl 2‐amino‐2‐oxoethylphosphonate. They were characterized by elemental analysis, IR, and NMR spectroscopy. Monodentate coordination by the phosphoryl group is suggested for the ligand on the basis of the spectral data. The stabilization is achieved by including a molecule of the solvent in the complexes 3a–d. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:128–131, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10112
Efficient synthesis and dehydration reaction of trichloromethylated 2‐(3‐phenyl‐5‐hydroxy‐4,5‐dihydro‐1H‐pyrazol‐1‐yl)‐4‐aryl‐5‐alkylthiazoles
Authors: Bonacorso Helio G. , Muniz Mauro N. , Wastowski Arci D. , Zanatta Nilo , Martins Marcos A. P. 
Published: March 2003

AbstractA convenient method for the synthesis of a novel series of 11, specifically substituted, noncondensed 5,5‐bicycles 2‐[3‐phenyl‐5‐hydroxy‐5‐trichloromethyl‐4,5‐dihydro‐1H‐pyrazol‐1‐yl]‐4‐aryl‐5‐alkylthiazoles (3a–k; 65–94% yield) from the reactions of 3‐phenyl‐5‐hydroxy‐5‐trichloromethyl‐4,5‐dihydro‐1H‐1‐pyrazolethiocarboxyamide (1) with substituted 2‐bromo‐4′‐acetophenones (2a–f) and 2‐bromo‐4′‐propiophenones (2g–k) is reported. Dehydration of compounds 3a–k with a mixture of concentrated sulfuric acid/chloroform furnished the corresponding 2‐[3‐phenyl‐5‐trichloromethyl‐1H‐pyrazol‐1‐yl]‐4‐aryl‐5‐alkylthiazoles (4a–k) in good yields (61–93%). © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:132–137, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10113
Arylation reaction of N‐dichlorophosphoryl‐P‐trichlorophosphazene
Authors: Arslan M. , Aslan F. , Ozturk A. I. 
Published: March 2003

AbstractThe reactions of N‐dichlorophosphoryl‐P‐trichlorophosphazene (Cl3PNPOCl2) with phenylmagnesium chloride, o‐tolylmagnesium chloride, p‐tolylmagnesium chloride, p‐chlorophenylmagnesium chloride, 2‐mesitylmagnesium bromide, and 2‐thienyl lithium were studied. The resulting pentaaryl phosphazenes R3PNP(O)R2 were separated by using column chromatography, their structures were defined by IR, elemental analysis, 1H, 13C, 31P NMR, and mass spectroscopy. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:138–143, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10114
Organotin(IV) complexes of N‐[(2Z)‐3‐hydroxy‐1‐methyl‐2‐butenylidene]glycine
Authors: Basu Baul Tushar S. , Dutta Sushmita , Masharing Cheerfulman , Rivarola Eleonora , Englert Ulli 
Published: March 2003

AbstractOrganotin(IV) derivatives of N‐[(2Z)‐3‐hydroxy‐1‐methyl‐2‐butenylidene]glycine have been synthesized and characterized by 1H, 13C, 119Sn NMR, 119Sn Mössbauer, and IR spectroscopy along with elemental analyses. The di‐ and triorganotin(IV) complexes were readily obtained from the reactions of organotin halides and sodium/potassium N‐[(2Z)‐3‐hydroxy‐1‐methyl‐2‐butenylidene]glycinate. The diorganotin compound reacted with Ph3SnCl in refluxing benzene to give the mixed organotin dinuclear complex of composition Ph2Sn(2‐OC(CH3)‐C(H)C(CH3)NCH2COO)·Ph3SnCl, which was characterized by single crystal X‐ray structure determination. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:149–154, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10116
Studies on reactivity of ketosulfones
Authors: Padmavathi V. , Sarma M. Rajagopala , Reddy K. Venugopal , Padmaja A. , Reddy D. Bhaskar 
Published: March 2003

AbstractThe cycloaddition of diazomethane, cyclocondensation of hydrazine hydrate, and cyclopropanation of TMSOI to 1‐aroyl‐2‐styrylsulfonylethenes were studied and different novel products thereby obtained were characterized with spectral parameters. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:155–159, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10117
The σ‐donating and π‐accepting properties of ortho‐Si(CH3)3 phosphinine macrocycles
Authors: Ferro V. R. , Omar S. , González‐Jonte R. H. , García de la Vega J. M. 
Published: March 2003

AbstractA theoretical investigation of both the ortho‐Si(CH3)3 phosphinine and some silacalix[n]phosphinines was performed. The optimized geometries agree well with those reported from X‐ray analysis and other structural studies. The silacalix[n]phosphinine macrocyle is very flexible because of the CSiC bridges. This, in turn, makes possible the formation of strained configurations in solid packed structures. In the silacalix[3]phosphinine, a PP bonding interaction that is presumably responsible for its structural and electronic features seems to exist. The molecular orbital calculations corroborate that both the π‐accepting properties and the σ‐donating capacities of the phosphinine unit may be enhanced by ortho‐Si(CH3)3 substitution. These features satisfy the proposal of the synthesizers as regards the production of macrocyclic phosphorus compounds, with good π‐accepting properties and strong σ‐donating capacities, which are sufficiently flexible as to encapsulate metals with coordination spheres of different geometries. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:160–169, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10118
Diels–alder reactions of anthracenes with C‐sulfonyldithioformates
Authors: El‐Sayed Ibrahim , Ali Omar M. , Fischer Andreas , Senning Alexander 
Published: March 2003

AbstractC‐Sulfonyldithioformates (2) (R1 = ArSO2, R2 = ArS) readily add to anthracene and 9‐methylanthracene (1) in a Diels–Alder fashion with formation of 9,10‐dihydro‐10,9‐(epithiomethano)anthracenes (3) which in turn may suffer thermally induced elimination of arenesulfinic acid to yield the 9‐anthracenedithiocarboxylic esters (4). The reactions with the unsymmetrical diene 9‐methylanthracene take place in a highly stereoselective fashion. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:170–174, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10119
Use of ELF and AIM parameter ratios for bond order characterization of two‐, three‐, and four‐coordinate gallium hydrides
Authors: Chesnut D. B. 
Published: March 2003

AbstractCalculations at the B3LYP/6‐311 + G(d,p)//B3LYP/6‐311 + G(d,p) level involving the electron localization function (ELF) and atoms‐in‐molecules (AIM) methods have been carried out for two‐, three‐, and four‐coordinate gallium hydrides present in Na and Li salts and as the isolated dianionic species, for some isoelectronic germanium compounds, and for several neutral gallium hydrides. Using the ratio of delocalization indices and bond basin populations referenced to reasonable standards, formal bond orders are derived. While chemically expected bond orders are found in most cases, the situation in the [HGaGaH]2− species appears to lie intermediate between bonds of order 2 and 3, and that for neutral trans‐bent HGaGaH is found to be best described as a bond of order 1. In these cases the larger bond order predicted by ELF bond basin populations evidently results from overlap of the bond basin into the lone pair (nonbonding) region of the molecule. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:175–185, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10120
A comparison of reactivity of (EtO)2P(O)CH2I with related non‐phosphorus‐containing iodides in the radical iodine atom transfer addition
Authors: Bałczewski Piotr , Białas Tomasz , Szadowiak Aldona 
Published: March 2003

AbstractBased on competitive reactions and 1H NMR measurements, it was found that (EtO)2P(O)CH2I is at least 2–3 orders of magnitude less reactive than other non‐phosphorus iodides of the EWG‐CH2I type (EWG = NC, COOMe, 4‐Br‐C6H4CO). MeSCH2I turned out to be totally unreactive in the title reaction. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:186–188, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10121
The double base impact in the dehydrochlorination of 1,2‐bis[bis(trimethylsilyl)methylchlorophosphino]ethane
Authors: Ionkin Alex S. , Marshall William J. 
Published: March 2003

Abstract1,2‐Bis[bis(trimethylsilyl)methylchlorophosphino]ethane was prepared by the reaction of 1,2‐bis(dichlorophosphino)ethane and the Grignard reagent of bis(trimethylsilyl)chloromethane. It adds DBN (1,5‐diazabicyclo[4.3.0]non‐5‐ene) in a 1:2 ratio. Subsequent treatment with t‐BuLi converts the adduct to a condensation product, which in its enamine form reacts with MgCl2 (still present from the preparation of 1) to give the cyclic magnesium diamide 2. By additional coordination of the two phosphine sites of the condensation product, 2 attains a tricyclic structure. An unchanged DBN molecule completes the pentacoordination of the magnesium atom. The structure of product 2 has been determined by single crystal X‐ray diffraction. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:197–199, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10122
Bonding and energetics in small clusters of gallium and arsenic
Authors: BelBruno Joseph J. 
Published: March 2003

AbstractDensity functional theory is used to study the electronic, geometric, and bonding properties of small Gan, Asm, and GanAsm clusters with up to eight atoms. New ground state structures for many of these clusters are reported. Electronic states, stabilities, and charges are also reported and discussed in terms of the bonding in the clusters. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:189–196, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10127
Nitroanilinomethanephosphonates derived from ferrocene and nitrobenzaldehyde
Authors: Lewkowski Jarosław , Rzeźniczak Monika , Skowroński Romuald 
Published: March 2003

AbstractA series of new aminophosphonates derived from ferrocene and nitrobenzene were synthesized. They were characterized by means of the 1H and 31P NMR spectroscopy as well as by their elemental analysis. Synthesis of esters was carried out without solvent as refluxing of the reagents in toluene or in acetonitrile gave no results. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:144–148, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10128
Characteristics of soil moisture in permafrost observed in East Siberian taiga with stable isotopes of water
Authors: Sugimoto A. , Naito D. , Yanagisawa N. , Ichiyanagi K. , Kurita N. , Kubota J. , Kotake T. , Ohata T. , Maximov T. C. , Fedorov A. N. 
Published: April 2003

AbstractSoil moisture and its isotopic composition were observed at Spasskaya Pad experimental forest near Yakutsk, Russia, during summer in 1998, 1999, and 2000. The amount of soil water (plus ice) was estimated from volumetric soil water content obtained with time domain reflectometry. Soil moisture and its δ18O showed large interannual variation depending on the amount of summer rainfall. The soil water δ18O decreased with soil moisture during a dry summer (1998), indicating that ice meltwater from a deeper soil layer was transported upward. On the other hand, during a wet summer (1999), the δ18O of soil water increased due to percolation of summer rain with high δ18O values.Infiltration after spring snowmelt can be traced down to 15 cm by the increase in the amount of soil water and decrease in the δ18O because of the low δ18O of deposited snow. About half of the snow water equivalent (about 50 mm) recharged the surface soil. The pulse of the snow meltwater was, however, less important than the amount of summer rainfall for intra‐annual variation of soil moisture.Excess water at the time just before soil freezing, which is controlled by the amount of summer rainfall, was stored as ice during winter. This water storage stabilizes the rate of evapotranspiration. Soil water stored in the upper part of the active layer (surface to about 120 cm) can be a water source for transpiration in the following summer. On the other hand, once water was stored in the lower part of the active layer (deeper than about 120 cm), it would not be used by plants in the following summer, because the lower part of the active layer thaws in late summer after the plant growing season is over. Copyright © 2002 John Wiley & Sons, Ltd.
Irreversible sorption of benzene in sandy aquifer materials
Authors: Baek Doo‐Sung , Kim Song‐Bae , Kim Dong‐Ju 
Published: April 2003

AbstractHydrocarbon compounds in aquifers are generally known to show a retardation effect due to sorption onto the surfaces of solid particles. In this study, we investigated the effect of sorption on the transport of benzene in sandy aquifer materials by conducting batch and column tests for both sandy aquifer materials and sandy materials to which had been added 0·5% powdered activated carbon. The batch test was conducted by equilibrating dry materials with benzene solutions of various initial concentrations, and by analysing the concentrations of benzene in the initial and equilibrated solutions using high‐performance liquid chromatography (HPLC). The column test was performed to monitor the concentrations of effluent versus time, known as a breakthrough curve (BTC). We injected KCl and benzene solutions as tracers into the inlet boundary as two different types of square pulse and step, and monitored the effluent concentrations at the exit boundary under a steady‐state condition using an electrical conductivity meter and HPLC. Simulation of benzene transport was performed using the convective–dispersive equation model with the distribution coefficients obtained from the batch test and the transport parameters of the conservative solute KCl from the column test. The observed BTCs of KCl and benzene for pulse injection showed that the arrival times of the peaks of both tracers coincided well, but the relative peak concentration of benzene was much lower than that of KCl. Comparison of the simulated and observed BTCs showed a great discrepancy for all cases of injection mode and material texture, indicating the absence of retardation effect. These results reveal that the predominant process affecting the benzene transport in the sandy aquifer materials is an irreversible sorption rather than retardation. This tentative conclusion was verified by simulation of benzene transport using an irreversible sorption parameter that led to a good agreement between the simulated and observed BTCs. Copyright © 2002 John Wiley & Sons, Ltd.
Hydraulic conductivity in upland blanket peat: measurement and variability
Authors: Holden J. , Burt T. P. 
Published: April 2003

AbstractA key parameter used in wetland hydrological and landform development models is hydraulic conductivity. Head recovery tests are often used to measure hydraulic conductivity, but the calculation techniques are usually confined to rigid soil theory. This is despite reports demonstrating the misapplication of rigid soil theory to non‐rigid soils such as peats. Although values of hydraulic conductivity calculated using compressible techniques have been presented for fenland peats, these data have never, to the authors' knowledge, been compared with such calculations in other peat types. Head recovery tests (slug withdrawal) were performed on piezometers at depths ranging from 10 to 80 cm from the surface on north Pennines blanket peats. Results were obtained using both rigid and compressible soil theories, thus allowing comparison of the two techniques. Compressible soil theory gives values for hydraulic conductivity that are typically a factor of five times less than rigid soil calculations. Hydraulic conductivity is often assumed to decrease with depth in upland peats, but at the study site in the northern Pennines it was not found to vary significantly with depth within the range of peat depths sampled. The variance within depth categories was not significantly different to the variance between depth categories showing that individual peat layers did not have characteristic hydraulic conductivity values. Thus, large lateral and vertical differences in hydraulic conductivity over short distances create problems for modelling but may help account for the high frequency of preferential flow pathways within what is otherwise a low matrix hydraulic conductivity peat. Hydraulic conductivity was found to vary significantly between sampling sites, demonstrating that hillslope‐ or catchment‐scale variability may be more important than plot‐scale variability. Values for compressibility of the peats are also reported. These generally decline with depth, and they also vary significantly between sampling sites. There are implications for the way in which measurements of hydraulic conductivity and other properties of blanket peat are interpreted, as the effects of environmental change in one part of a peat catchment may be very different to those in another. Copyright © 2002 John Wiley & Sons, Ltd.
Observation and estimation of evaporation from the ground surface of the cryosphere in eastern Asia
Authors: Zhang Yinsheng , Ohata T. , Ersi Kang , Tandong Yao 
Published: April 2003

AbstractThe characteristics of evaporation from the ground surface of Asian cryosphere sites are presented, as estimated by the lysimeter method, a profile method, and a heat budget method. The observation sites were located on the eastern Tibetan Plateau, in the Qilian and Tianshan Mountains of China, and in eastern Siberia. The lysimeter method has been demonstrated to be a reliable observation technique for estimating daily evaporation from the land surface, given suitable experiment design and operation. Daily mean evaporation varied within the range of 0·3 to 3·5 mm on the permafrost surface, and regional differences in evaporation were strongly related to surface soil moisture. Locally, topography, by way of its influence on surface soil moisture, was found to control evaporation systematically. Seasonality of ground evaporation in permafrost regions is dominated by thaw–freeze cycles at the surface; evaporation from the melting permafrost surface is up to four to seven times greater than that from frozen ground. In forested terrain, the interception of precipitation can reduce daily evaporation by 60 to 70%. Sublimation from the snow surface was observed at some sites in the range of 0·2 to 1·0 mm daily; atmospheric conditions, such as wind speed and saturation deficit, were dominant factors in determining snow sublimation. Copyright © 2003 John Wiley & Sons, Ltd.
Nutrient budget of a montane evergreen broad‐leaved forest at Ailao Mountain National Nature Reserve, Yunnan, southwest China
Authors: Liu Wenyao , Fox John E. D. , Xu Zaifu 
Published: April 2003

AbstractHydrological fluxes and associated nutrient budget were studied during a 2 year period (1998–99) in a montane moist evergreen broad‐leaved forest at Ailao Mountain, Yunnan. Water samples of rainfall, throughfall, and stemflow, and of surface runoff, soil water, and stream flow were collected bimonthly to determine the concentration and fluxes of nutrients. Soil budgets were determined from the difference between precipitation input (including nutrient leaching from canopy) and output via runoff and drainage.The forest was characterized by low canopy interception and surface runoff, and high percolation and stream flow. Concentrations of nutrients were increased in throughfall and stemflow compared with precipitation. Surface runoff and drainage water had higher nutrient concentrations than precipitation and stream water. Total nitrogen and NH4+‐N concentrations were higher in soil water than stream water, whereas K+, Ca2+, and Mg2+ concentrations were lower in the former than the latter. Annual nutrient fluxes decreased with soil depth following the pattern of water flux. Annual losses of most nutrient elements via stream flow were less than the corresponding inputs via throughfall and stemflow, except for calcium, for which solute loss was greater than the inputs via precipitation. Leaching losses of that element may be compensated by weathering. Losses of nitrogen, phosphorus, potassium, magnesium, sodium, and sulphur could be replaced through atmospheric inputs. Copyright © 2002 John Wiley & Sons, Ltd.
Suspended sediment transport during tropical‐cyclone floods in Fiji
Authors: Kostaschuk Ray , Terry James , Raj Rishi 
Published: April 2003

AbstractFlow records, rising‐stage sediment samplers, and a sand suspension model are used to examine suspended sediment concentrations during major floods caused by tropical cyclones TC Joni and TC Kina in the Rewa River, Fiji. The highest concentrations of total suspended solids were measured during the early stages of TC Kina. The suspension model predicts higher sand concentrations for TC Kina compared with TC Joni because of the larger slope and higher shear stresses during Kina. Extremely high wash load concentrations early in TC Kina are at least partly due to remobilization of fine sediment deposited during the earlier TC Joni flood. Samples from the TC Kina had volumetric concentrations larger than 5%, indicating hyperconcentrated streamflows. Mass‐density shear stresses in the hyperconcentrated flows are up 1·6 times larger than clear‐water shear stresses, but they occur early during low stages of the flood and probably do not result in severe bed erosion. Copyright © 2002 John Wiley & Sons, Ltd.