bluuebunny/crossref_metadata_2025_split huggingface dataset:
The reaction OF N‐dichlorophosphoryl‐ P‐trichlorophosphazene with alkyl grignard reagents
Authors: Aslan F. , Ozturk A. I. , Arslan M. 
Published: June 2003

AbstractThe reactions of N‐dichlorophosphoryl‐P‐trichlorophosphazene Cl3PNP(O)Cl2 (1) with benzylmagnesium bromide, 2‐phenylethylmagnesium bromide, trimethylsilylmethylmagnesium chloride, n‐butylmagnesium bromide, cyclohexylmagnesium bromide, cyclopentylmagnesium bromide, tert‐butylmagnesium bromide, iso‐propylmagnesium bromide, and ethylmagnesium bromide were studied. Tri‐ and pentaalkyl phosphazenes were obtained in very poor yield from trimethylsilylmethylmagnesium chloride and cyclohexylmagnesium bromide, respectively. Trialkylphosphoryl compounds formed from benzyl‐, 2‐phenylethyl‐, and n‐butylmagnesium bromide. No phosphorus compound could be isolated from the reaction of 1 with t‐butyl‐, cyclopentyl‐, iso‐propyl‐, and ethylmagnesium bromide. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:413–416, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10153
1,3,2‐Oxazastibinanes: Novel six‐membered heterocycles
Authors: Singh Satnam , Jha N. K. 
Published: June 2003

AbstractThe hitherto unreported oxazastibinanes 3 have been synthesized by the sodium borohydride reduction of 3‐phenyl‐1‐arylamino‐3‐oxopropane (1) and subsequent cyclization of the disodium salt of 3‐phenyl‐1‐arylamino‐3‐hydroxypropane (2) with R3SbBr2 (R = Ph, p‐tolyl, or mesityl). These compounds have been characterized by elemental analyses, molecular weight determination, and by IR, far IR, 1H, and 13C NMR spectral studies. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:417–420, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10155
1,3,4‐Thia‐ and ‐selenadiazole and 1,2,4‐triazolo[4,3‐a]pyrimidine derivatives from hydrazonoyl halides
Authors: Abdel‐Riheem Nadia A. , Rateb Nora M. , Al‐Atoom Ali A. , Abdelhamid Abdou O. 
Published: June 2003

Abstract1,2,4‐Triazolo[4,3‐a]pyrimidines, thiadiazolines, selenadiazolines, and unsymmetrical azines were synthesized via reactions of a 4‐isopropylbenzoyl bromide 4‐nitrophenylhydrazone with each of potassium thiocyanate, potassium selenocyanate, ethyl 6‐methyl‐4‐[4‐(methylethyl)phenyl]‐2‐methylthio‐3,4‐dihydropyrimidine‐5‐carboxylate, and alkyl carbodithioate. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:421–426, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10156
Syntheses of 3,4,7‐triazaacenaphthylene and pyrido[3,4,5‐de]cinnoline derivatives
Authors: Elassar Abdel‐Zaher A. , El‐Kholy Yehya M. 
Published: June 2003

AbstractThe title compounds were prepared by four different routes: (1) reaction of cycloalkanopyridazines 3a–e with trichloroacetonitrile in basic medium; (2) reaction of 3a–d with DMF DMA, followed by nucleophilic treatment with a primary amine; (3) reaction of 2‐(dimethylamino)methylene‐cycloalkylidene‐malononitrile with arene diazonium salt, followed by amine treatment; (4) reaction of cycloalkylidenemalononitrile with phenyl or benzoyl isothiocyanate and heating the product with diazoaminobenzene. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:427–433, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10168
Conversion of 2(3H)‐furanones bearing indole nuclei into novel amide, pyrrolone, and imidazole derivatives
Authors: Hamad Elgazwy Abdel‐Sattar S. , Zaky H. T. , Mohamed M. I. , Ahmed H. M. , Kandile N. G. 
Published: June 2003

Abstract2(3H)‐Furanones 1a–d having exocyclic double bond and N‐acetylisatin nucleus were converted into the corresponding novel amides, pyrrolones, and imidazoles via nitrogen nucleophiles. All purposed structures were confirmed by NMR, mass spectra GC/MS, and chemical evidence. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:434–442, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10175
Fragmentation‐related phosphinylations using 2‐aryl‐2‐phosphabicyclo[2.2.2]oct‐ 5‐ene‐ and ‐octa‐5,7‐diene 2‐oxides
Authors: Keglevich György , Szelke Helga , Bálint Ágnes , Imre Tímea , Ludányi Krisztina , Nagy Zoltán , Hanusz Miklós , Simon Kálmán , Harmat Veronika , Tőke László 
Published: June 2003

AbstractA series of new P‐methylphenyl P‐heterocycles are introduced. The para and ortho substituted 2,5‐dihydro‐1H‐phosphole oxides (1a and 1b) were converted to the double‐bond isomers (A and B) of 1,2‐dihydrophosphinine oxides (3a and 3b) via the corresponding phosphabicyclo[3.1.0]hexane oxides (2a or 2b). Isomeric mixture (A and B) of the dihydrophosphinine oxides (3a and 3b) gave, in turn, the isomers (A and B) of phosphabicyclo[2.2.2]oct‐5‐enes (4a and 4b) or a phosphabicyclo[2.2.2]octa‐5,7‐diene (5) in Diels‐Alder reaction with dienophiles. The bridged P‐heterocycles (4 and 5) were useful in the photo‐ or thermoinduced fragmentation‐related phosphinylation of hydroxy compounds and amines. The new precursors (4a and 4b) were applied in mechanistic investigations. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:443–451, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10176
Dichloro(diisopropylamino)phosphonio[5(4H)oxopyrazol‐4‐ylide‐5‐one]: Synthesis and properties
Authors: Konovets A. I. , Kostyuk A. N. , Pinchuk A. M. , Tolmachev A. A. , Fischer A. , Jones P. G. , Schmutzler R. 
Published: June 2003

AbstractChlorination of the 4‐[chloro(diisopropylamino)phosphino]pyrazole 1 leads to the dichlorophosphonium chloride 2, which immediately after its formation transforms into the dichloro(diisopropylamino)phosphonio[5(4)oxopyrazol‐4‐ylide‐5‐one] 3, as a result of dealkylation through loss of ethyl chloride.
Reactions of 3 with various nucleophilic reagents were studied. The partial hydrolysis of 3 in the presence of nitriles, resulting in new phosphorus‐containing cyclic systems, is of particular interest. It was demonstrated that chlorination of the P‐dichloropyrazolylphosphine A leads to the stable tetrachlorophosphorane 12. The CP bond of 12 is broken upon heating. An X‐ray structure determination of compound 11b revealed a planar central heterocycle (mean deviation 0.029 Å). © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:452–458, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10177
Utility of a 2‐aminothiophene‐3‐carboxamide in the synthesis of thienopyridines and thienopyrimidines
Authors: Mohareb Rafat M. , Sherif Sherif M. , Gaber Hatem M. , Ghabrial Sami S. , Aziz Susan I. 
Published: June 2003

Abstract2‐Amino‐4,5,6,7‐tetrahydrobenzo[b]‐ thiophene‐3‐carboxamide (1) was prepared according to Gewald procedure. Its reactivity toward a variety of chemical reagents was studied to give thienopyridines and ‐pyrimidines. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:459–467, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10179
Solvent‐free cycloaddition reaction of 3‐indolylimines with chloroacetyl chloride under microwave irradiation
Authors: Dandia Anshu , Singh Ruby , Sharma Pragati 
Published: June 2003

AbstractSolvent‐free approach is developed for the rapid synthesis of spiro[azetidine‐indoles] 6a–g on basic alumina supported potassium carbonate (K2CO3–Al2O3) from the cycloaddition reaction of indolylimines 3 and chloroacetyl chloride 4 as synthons using microwaves. The procedure neither required toxic and hazardous base nor volatile solvents. 3 was synthesized in situ by the neat reaction of indole‐2,3‐diones 1 and fluorinated anilines 2 under microwave irradiation. Solvent‐free aminoalkylation of spiro compounds 6a and 6b has been carried out under microwaves. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:468–473, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10180
Cycloaddition of N‐(2,2,2‐trichloroethylidene)‐substituted carboxamides and carbamates to 1,2,4‐thiadiazol‐5(2H)‐imines
Authors: Zyabrev Vladimir S. , Rensky Mikhail A. , Rusanov Eduard B. , Drach Boris S. 
Published: June 2003

Abstract1,2,4‐Thiadiazol‐5(2H)‐imines 4 react with N‐(2,2,2‐trichloroethylidene)‐substituted amides 5 to form [3 + 2]‐cycloaddition products 6 featured by an extra coordination of the ring sulfur atom to the terminal nitrogen atom of the side 1,3‐diazapropenylidene group, as established by X‐ray diffraction investigation. This coordination evidently plays an important role in the alkylation of compounds 6 into 8 at the oxygen atom under mild conditions. The SN bond “switch‐over” restoring the original 1,2,4‐thiadiazole ring occurs therewith. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:474–480, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10182
A report on the 29th symposium on heteroatom chemistry of the chemical society of Japan
Authors: Ishii Akihiko , Sugihara Yoshiaki , Nakayama Juzo 
Published: June 2003

AbstractThe 29th domestic Chemical Society of Japan Symposium on Heteroatom Chemistry was held in Hiroshima during the period of December 12–14, 2002, under the management of Tetsuo Otsubo of Hiroshima University. About 250 chemists from various academic institutes and industries enjoyed four plenary lectures, 44 oral presentations, and 53 poster presentations. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:387–398, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10186
Suspended sediment dynamics in a steep, glacier‐fed mountain stream, Place Creek, Canada
Authors: Richards G. , Moore R. D. 
Published: June 2003

AbstractThis study examined suspended sediment concentration (SSC) during the ablation seasons of 2000 and 2001 in Place Creek, Canada, a steep, glacier‐fed mountain stream. Comparison of stream flow in Place Creek with that in an adjacent, almost unglacierized catchment provided a rational basis for separating the ablation seasons into nival, nival–glacial, glacial and autumn recession subseasons. Distinct groupings of points in plots of electrical conductivity against discharge supported the validity of the subseasonal divisions in terms of varying hydrological conditions. Relationships between SSC and discharge (Q) varied between the two study seasons, and between subseasons. Hysteresis in the SSC–Q relationship was evident at both event and weekly time‐scales. Some suspended sediment released from pro‐glacial Place Lake (the source of Place Creek) appeared to be lost to channel storage at low flows, especially early in the ablation season, with re‐entrainment at higher flows. Multiple regression models were derived for the subseasons using predictor variables including Q, Q2, the change in Q over the previous 3 h, cumulative discharge over the ablation season, total precipitation over the previous 24 h and SSC measured at 1500 hours as an index value for each day. The models produced adjusted R2 values ranging from 0·71 to 0·91, and provided tentative insights into the differences in SSC dynamics amongst subseasons. Introduction of the index value of SSC significantly improved the model fit during the nival–glacial and glacial subseasons for both years, as it adjusts the model to the current condition of sediment supply. Copyright © 2003 John Wiley & Sons, Ltd.
Effect of spatial variation characteristics on contouring of design storm depth
Authors: Cheng Ke‐Sheng , Wei Chiang , Cheng Yen‐Ben , Yeh Hui‐Chung 
Published: June 2003

AbstractThe ordinary kriging method, a geostatistical interpolation technique, was applied for developing contour maps of design storm depth in northern Taiwan using intensity–duration–frequency (IDF) data. Results of variogram modelling on design storm depths indicate that the design storms can be categorized into two distinct storm types: (i) storms of short duration and high spatial variation and (ii) storms of long duration and less spatial variation. For storms of the first category, the influence range of rainfall depth decreases when the recurrence interval increases, owing to the increasing degree of their spatial independence. However, for storms of the second category, the influence range of rainfall depth does not change significantly and has an average of approximately 72 km. For very extreme events, such as events of short duration and long recurrence interval, we do not recommend usage of the established design storm contours, because most of the interstation distances exceed the influence ranges. Our study concludes that the influence range of the design storm depth is dependent on the design duration and recurrence interval and is a key factor in developing design storm contours. Copyright © 2003 John Wiley & Sons, Ltd.
Determining long time‐scale hyporheic zone flow paths in Antarctic streams
Authors: Gooseff Michael N. , McKnight Diane M. , Runkel Robert L. , Vaughn Bruce H. 
Published: June 2003

AbstractIn the McMurdo Dry Valleys of Antarctica, glaciers are the source of meltwater during the austral summer, and the streams and adjacent hyporheic zones constitute the entire physical watershed; there are no hillslope processes in these systems. Hyporheic zones can extend several metres from each side of the stream, and are up to 70 cm deep, corresponding to a lateral cross‐section as large as 12 m2, and water resides in the subsurface year around. In this study, we differentiate between the near‐stream hyporheic zone, which can be characterized with stream tracer experiments, and the extended hyporheic zone, which has a longer time‐scale of exchange. We sampled stream water from Green Creek and from the adjacent saturated alluvium for stable isotopes of D and 18O to assess the significance and extent of stream‐water exchange between the streams and extended hyporheic zones over long time‐scales (days to weeks). Our results show that water residing in the extended hyporheic zone is much more isotopically enriched (up to 11‰ D and 2·2‰ 18O) than stream water. This result suggests a long residence time within the extended hyporheic zone, during which fractionation has occurred owing to summer evaporation and winter sublimation of hyporheic water. We found less enriched water in the extended hyporheic zone later in the flow season, suggesting that stream water may be exchanged into and out of this zone, on the time‐scale of weeks to months. The transient storage model OTIS was used to characterize the exchange of stream water with the extended hyporheic zone. Model results yield exchange rates (α) generally an order magnitude lower (10−5 s−1) than those determined using stream‐tracer techniques on the same stream. In light of previous studies in these streams, these results suggest that the hyporheic zones in Antarctic streams have near‐stream zones of rapid stream‐water exchange, where ‘fast’ biogeochemical reactions may influence water chemistry, and extended hyporheic zones, in which slower biogeochemical reaction rates may affect stream‐water chemistry at longer time‐scales. Copyright © 2003 John Wiley & Sons, Ltd.
Development of a remotely controlled debris flow monitoring system in the Dolomites (Acquabona, Italy)
Authors: Tecca Pia R. , Galgaro Antonio , Genevois Rinaldo , Deganutti Andrea M. 
Published: June 2003

AbstractDirect measurements of the hydrological conditions for the occurrence of debris flows and of flow behaviour are of the outmost importance for developing effective flow prevention techniques. An automated and remotely controlled monitoring system was installed in Acquabona Creek in the Dolomites, Italian Eastern Alps, where debris flows occur every year. Its present configuration consists of three on‐site stations, located in the debris‐flow initiation area, in the lower channel and in the retention basin. The monitoring system is equipped with sensors for measuring rainfall, pore‐water pressure in the mobile channel bottom, ground vibrations, debris flow depth, total normal stress and fluid pore‐pressure at the base of the flow. Three video cameras take motion pictures of the events at the initiation zone, in the lower channel and in the deposition area. Data from the on‐site stations are radio‐transmitted to an off‐site station and stored in a host PC, from where they are telemetrically downloaded and used by the Padova University for the study of debris flows. The efficiency of the sensors and of the whole monitoring system has been verified by the analysis of data collected so far. Examples of these data are presented and briefly discussed. If implemented at the numerous debris‐flow sites in the Dolomitic Region, the technology used, derived from the development of this system, will provide civil defence and warn residents of impending debris flows. Copyright © 2003 John Wiley & Sons, Ltd.
Near‐infrared spectroscopy of a hydroecological indicator: new tool for determining sustainable yield for Floridan aquifer system
Authors: Bacchus Sydney T. , Archibald Douglas D. , Brook George A. , Britton Kerry O. , Haines Bruce L. , Rathbun Stephen L. , Madden Marguerite 
Published: June 2003

AbstractPond‐cypress (Taxodium ascendens Brong.) is a dominant canopy species in depressional wetlands of the south‐eastern Coastal Plain. Unsustainable withdrawals from the karst Floridan aquifer system have caused premature decline and death of pond‐cypress trees, presumably owing to altered hydroperiods (which alter the flow of water and nutrients in trees). There has been no scientifically based means to determine sustainable yield from this regional aquifer system or to detect early stages of physical/ecological damage associated with groundwater mining and aquifer storage and recovery (ASR, which also can alter natural hydroperiods). In this study, the relationship between visual symptoms (indicators) of stress or premature decline, and spectral reflectance was evaluated using dried, milled branch tips collected from natural stands of mature pond‐cypress. Depressional systems evaluated represented four of the six aquifer system subregions where subsurface perturbations from groundwater mining: (i) were presumed not to be occurring (reference wetlands); (ii) may be occurring but are not documented; and (iii) have been confirmed. Sampled trees were assigned to one of three stress classes (1, no/minimal; 2, moderate; 3, severe) based on the visual indicators. Partial least squares–linear discriminant analysis of second derivative spectral transformations in the visible/shortwave near‐infrared (NIR) region (400–1100 nm) and the NIR region (1100–2500 nm) was used to evaluate the samples in assigned classes.Class 1 samples were discriminated from combined class 2 and 3 samples in the NIR region with 100% and 97% accuracy for consecutive winter sample periods (before bud‐break). The percentage of correctly classified samples in this spectral region was lower (85%) for summer samples (full leaf‐out). Second‐derivative models for the NIR region developed from the winter data sets predicted assigned classes for alternate winter's samples with an accuracy of 97% and 100%. High correlation between spectral reflectance of dried, milled branch tips collected from mature pond‐cypress in winter and visual indicators of premature decline suggests in situ pond‐cypress are hydroecological indicators of anthropogenic subsurface hydroperiod perturbations. This approach provides objective means for early detection of unsustainable aquifer yield and adverse impacts from ASR activities in the south‐eastern Coastal Plain. Used in conjunction with hydrological monitoring and modelling, the hydroecological indicators should provide the means with which sustainable yield in the south‐eastern Coastal Plain can be achieved and maintained. Copyright © 2003 John Wiley & Sons, Ltd.
Hydraulic conditions, oxygenation, temperatures and sediment relationships of bedwork watermeadows
Authors: Cutting Roger L. , Cook Hadrian F. , Cummings Ian P. F. 
Published: June 2003

AbstractThis study investigates the interactions of water, oxygen, temperature, suspended sediment and topsoil texture of bedwork watermeadows. These ancient grassland irrigation systems survive on the floodplain around Salisbury, England but recent interest in their conservation and rehabilitation is not matched by detailed understanding of their operation. The dominant ‘bedwork’ form, by which water runs along the top of ridges and down ‘panes’, enables water to move swiftly through the sward and drain to avoid stagnation. This investigation demonstrates that condition of surface flow and rates of infiltration encourage the solution of atmospheric oxygen in the water, offsetting potentially anaerobic conditions in the root zone. Temperature conditions imparted by the flow were measured and found to be conducive to the early growth of grass. Whereas the sediment budget was found to be conservative under a steady‐state hydraulic regime, there is substantial ingress of suspended sediment at the start of an irrigation event and the sward traps coarse to medium‐sized silt particle fractions and influences topsoil texture. It is concluded that a study of watermeadow operation permits insights into the operation of floodplain processes in general. Copyright © 2003 John Wiley & Sons, Ltd.
Sediment yield modelling for small agricultural catchments: land‐cover parameterization based on remote sensing data analysis
Authors: Paringit Enrico C. , Nadaoka Kazuo 
Published: June 2003

AbstractVegetation and soil properties and their associated changes through time and space affect the various stages of soil erosion. The island of Ishigaki in Okinawa Prefecture, Japan is of particular concern because of the propensity of the red‐soil‐dominated watersheds in the area to contribute substantial sediment discharge to adjacent coastal areas. This paper discusses the application of remote sensing techniques in the retrieval of vegetation and soil parameters necessary for the distributed soil‐loss modelling in small agricultural catchments and analyses the variation in erosional patterns and sediment distribution during rainfall events using numerical solutions of overland flow simulations and sediment continuity equations. To account for the spatial as well as temporal variability of selected parameters of the soil‐loss equations, a method is proposed to account for the variability of associated vegetation cover based on their spectral characteristics as captured by remotely sensed data. To allow for complete spatial integration, modelling the movement of sediment is accomplished under a loose‐coupled GIS computational framework. This study lends a theoretical support and empirical evidence to the role of vegetation as a potential agent for soil erosion control. Copyright © 2003 John Wiley & Sons, Ltd.