An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

N-Protected L-phenylalanines 1a,b were transformed, via the corresponding Weinreb amides 2 and ethynyl ketones 3, into chiral enamino ketones 4 (Scheme 1). Similarly, L-threonine 6 was transformed in four steps into the enamino ketone 10. Cyclocondensations of 4 and 10 with pyrazolamines 11, benzenecarboximidamide (12), and hydrazine derivatives 18 afforded N-protected 1-heteroaryl-2-phenyl-ethanamines 15a-e, 16, 17, and 21a-k and 1-heteroaryl-1-aminopropan-2-ols 23a,b in good yields (Schemes 2 and 3). Finally, deprotection by catalytic hydrogenation furnished free amines 22a-g and 24a,b (Scheme 3).

On the basis of the enaminone methodology, libraries of 3-amino-4H-quinolizin-4-ones, fused 3-amino4H-pyrimidin-4-ones, and fused 3-amino-2H-pyran-2-ones were synthesized by the solid-phase and by the solution-phase parallel synthesis. The solution-phase approach turned out to be advantageous over the solid-phase approach. The solution-phase synthesis afforded, in most cases, analytically pure products in high yields, whereas the solid-phase approach gave products in poor yields and in low purity.

Cycloadditions of (1Z,4R*,5R*)-4-benzoylalnino-5-phenylpyrazolidin-3-on-1-azomethine imines to olefinic dipolarophiles were studied. Stereochemistry of cycloadditions to azomethine imines 3 was found to be controlled by stereodirecting phenyl group at position 3, as well as by the ortho-substituents at the aromatic ring at position 1'. The structures of dipoles and products were confirmed by NMR and X-ray diffraction. (c) 2005 Elsevier Ltd. All rights reserved.

(S)-3-(Dimethylamino)methylidene-5-benzyltetramic acid derivatives 4a and 4b were prepared in three steps from N-protected (S)-3-phenylaianines la and 1b, respectively. Similarly, N-[N-(benzyloxycarbonyl)glycyl]glycine (1c) was transformed into the enaminone 4c. Acid-catalysed coupling of enaminones 4a-c with aliphatic, aromatic, and heteroaromatic primary amines 5-34 afforded the corresponding N(Y)-substituted 3-aminomethylidene-tetramic acid derivatives 35-64 in 29-96% yields.

N-Substituted (1R,5S)-4-aminomethylidene-1,8,8-trimethyl-2-oxabicyclo[3.2.1]octan-3-ones were prepared in three steps from (1R)-(+)-camphor via coupling of (2R,4E, 5S)-3-[(dimethylamino)methylidene]- 1, 8,8-trimethyl-2-oxabicyclo[3.2.1] octan-3-one with primary amines. N,N'-Bis-{[(1R,5S)-1,8,8-trimethyl-3-oxo-2-oxabicyclo[3.2.1]oct-4-ylidene]methyl} benzene-1,2-diamine was used as the ligand in the preparation of the corresponding coordination compounds with palladium(II), copper(II) and nickel(II). The structures were determined by 2D NMR techniques, NOESY spectroscopy and X-ray diffraction. (C) 2004 Elsevier Ltd. All rights reserved.

Benzyl (3S,4E)-4-[(dimethylamino)methylidene]-5-oxotetrahydrofuran-3-ylcarbamate 5 was prepared in 4 steps from L-aspartic acid 1. Acid-catalysed treatment of 5 with amines 6 gave the dimethylamine substitution products 7. Benzyl (3S,4E)-4-[(arylamino)methylidene]-5-oxotetrahydrofuran-3-ylcarbamates 7c-n were prepared by parallel solution phase synthesis from 5 and anilines 6c-n in 45-94% yields. Enaminone 5 reacted with potassium cyanide in the presence of 18-crown-6 to afford benzyl 4-cyanomethyl-5-oxo-2,5-dihydrofuran-3-ylcarbamate 9. Upon reaction of 9 with nitrile oxide 10 the 1,2,4-oxadiazole derivative 11 was isolated in poor yield, while treatment of 9 with diazomethane 12 furnished the methylation products 13 and 14.

Treatment of methyl (S)-5-[(E)-(dimethylamino) methylidene]-2-oxotetrahydrofuran-5-carboxylate (2) with potassium cyanide in acetic acid gave (S)-5- [(E) -cyanomethylidene]-2-oxotetrahydrofuran-5-carboxylate (3), which was used as chiral dipolarophile in 1,3-dipolar cycloadditions. Reactions of 3 with diazomethane (4) and nitrile oxides 5a-c afforded spirolactones 6-8 in 24-34% diastereomeric excess, while with diazomethane (4) in the presence of triethylamine, methyl 3-cyanomethyl-2-methoxyfuran-5-carboxylate (12) was obtained.

Cycloadditions of various 1,3‐dipoles to methyl (S)‐1‐tert‐butoxycarbonyl‐3‐[(E)‐cyanomethylidene]‐2‐pyrrolidinone‐5‐carboxylate (9) were studied. Reactions of 9 with diazomethane (10) and 2,4,6‐trimethoxy‐benzonitrile oxide (11), carried out under neutral conditions, gave the corresponding optically active spiro compounds 16‐18 with low diastereoselectivity (20‐30% diastereomeric excess). On the other hand, reactions of 9 with nitrile oxide 11 and nitrile imines 14, 15, carried out in the presence of a base, afforded racemic pyrazolo and isoxazolo fused 2‐pyrrolidinones 21‐23 in 82‐86% diastereomeric excess. Optically active dipolarophile 9 was isomerized in the presence of basic alumina to give methyl (RS)‐1‐tert‐butoxy‐carbonyl‐3‐cyanomethyl‐1,2‐dihydro‐2‐oxo‐5H‐pyrrole‐5‐carboxylate (19). Treatment of the racemic dipolarophile 19 with dipoles 11 and 14, afforded fused 2‐pyrrolidinones 23 and 21. These observations support compound 19 as the key‐intermediate in the formation of racemic cycloadducts 21‐23.

The influence of parent rock and soil material on the corrosion rate of metallic fragments that remained in soil after World War I in the Soča front area (Slovenia), as well as the corrosion products of these fragments, were studied. The results of corrosion tests did not indicate appreciable differences in corrosion rates between various corrosion media. Consequently, the corrosion rates are influenced mostly by soil aeration, soil humidity and also by microstructures of alloys. Soil type seems to have the most influence on corrosion products. For the pH and Eh ranges that prevail in the studied soils, goethite is the only stable iron mineral. Lead minerals are not stable, and lead, in a Pb 2+ cation form, is probably adsorbed onto some minerals – especially goethite – or is bound with organic matter. In distric brown soil, lead stays in the cation form as Pb 2+ because of high soil acidity. Cuprite is stable in rendzina and brown soil on limestone, whereas in distric brown soil copper stays in solution as Cu 2+ .

Soil samples were collected at 147 locations in a 1km2 grid pattern in southern Austria and northern Slovenia in order to evaluate natural versus anthropogenic influences of Pb–Zn mining and smelting activities in this area. The territory consists predominantly of Triassic limestones and dolomites containing Pb and Zn ore bodies. Total concentrations of 26 chemical elements in 507 soil samples were determined by X-ray fluorescence spectrometry. Elemental distributions were studied by univariate statistical analysis and by R-mode factor analysis. 79% of the total variability in data is explained by four factors. The factor that is loaded with Pb and Zn explains more than 10% of the variance. Results of the statistical analysis were plotted as elemental and factor score geochemical maps. The results show that concentrations of most elements increase on the average with soil depth. Several elements (Cr, Cu, Ni, Pb and Zn) tend to accumulate in organic horizons. They indicate heavy airborne technogenic pollution from the time of operation of the smelter at Žerjav. Geochemical maps indicate distinctions in elemental concentrations in soils on different bedrock and in different soil types as well as sources of elemental enhancement in soils. Besides the significant technogenic anomaly of Pb and Zn in the top few centimetres of the soil in the vicinity of the smelter, geogenic influence of mineralized bedrock on illuvial horizons in several places is indicated.

For experimental geochemical mapping soil was sampled in 5×5 km regular grid in Istria and the Slovenian littoral (Croatia and Slovenia). The territory consists predominantly of karstified limestones and dolomites, and of flysch beds exposed in two basins, Istrian and Brkini. In addition to soil, stream sediment was also collected in the flysh area. Sampling was performed according to an analysis of variance design that permitted one to estimate the effects of the sample medium, geographic position, sampling error and analytical error. The analysis of variance of chemical variables indicated that soil and stream sediment as sampling media lead to similar results in producing geochemical maps. The largest differences with respect to the lithologic substrate of soil is indicated by calcium. As shown by the geochemical map, calcium in soil is high on the Istrian flysch beds, and low on limestones as well as on the flysch beds of the Brkini basin. The two soils also differ in mineralogy. The reason for this difference seems to lie in soil genesis on limestone and on flysch, and in the variable calcium content of flysch beds. The results of Q-mode factor analysis confirmed the adherence of soil and stream sediment of the two flysch basins to two differing groups. This difference was discovered by geochemical mapping. The hypothesis of differing calcium content in the rocks of the two basins was confirmed by the investigation of fresh and weathered rocks and soils in eight profiles sampled in the Brkini and Istrian flysch basin. It was found that the sandstone and calcarenitic samples from the Istrian basin contain an average factor of 3.5 more Ca than those of the investigated Brkini basin, and the samples of Istrian marls 4 times more Ca than those of the Brkini siltstones. Furthermore, the investigated weathered rocks and soils that originated from these rocks in the Istrian basin contain considerably more Ca than in the Brkini basin. In comparison with sandstone and siltstone samples of the Brkini basin, sandstone, calcarenite and marl samples of the Istrian flysch basin contain less clay minerals, quartz and feldspars and more calcite.

Stream and flood plain sediments along the valley of the Idrijca River were systematically sampled. Upstream of the mercury mining town of Idrija, the Hg in stream sediment varies around 2 mg/kg. Mecury contents in the region from Idrija downstream to the town of Spodnja Idrija are from 100 to 1,000 mg/kg. Downstream from Spodnja Idrija, sediments contain lower Hg (from 5 to 300 mg/kg). Recent overbank sediments are enriched relative to the stream sediments downstream of Idrija. River flood plain sediments that represent an accumulation of polluted sediments have Hg contents of 100 to 200 mg/kg.

Surface drainage samples, the usual media employed in mapping national territories, cannot be used for the geochemical mapping of carbonate terrains because of the absence of a regular surface-drainage pattern on karst. Suitable sampling media have been studied in Yugoslavia, one-third of which consists of karst terrain. Sampling designs for the work were based on analysis of variance techniques. During initial investigations of various sampling materials in northwest Yugoslavia sediment and aquatic moss from karst springs, along with soil, were established as the most appropriate media. Modified sampling procedures were then carefully applied along the entire Yugoslav karst belt, which includes terrains of contrasting topography, climate, pedology and vegetation. The studies indicate that climate and relief do not systematically influence the geochemical composition of soil. Regional and local variability was assessed for 21 chemical elements and the feasibility of producing stable regional geochemical maps was determined for a number of elements on the basis of sampling aquatic moss and sediment from karst springs and soil.

A total of 195 sandstones and shales from red-beds of the Catskill Formation have been analyzed for Sb by epithermal neutron activation and for major elements by plasma emission spectrometry. The mean Sb content is 1.5 ppm for shales and 0.7 ppm for sandstone, in good agreement with the relatively few previous determinations for sedimentary rocks. Sb correlates positively with components of the fine-grained fraction (mica, Fe-oxide, chlorite) and with chemical elements in this fraction (Fe, Al, Mg, K, etc.), and correlates inversely with quartz and SiO2. Gray-green sandstones and shales average slightly less Sb than red sandstones and shales, probably because of diagenetic redistribution of Sb, which is concentrated along with Cu, Ag, As and U in red-bed Cu occurrences of the region. The strongest correlation is with Fe, suggesting that Fe-oxides may be a major host. Factor analysis also suggests an affinity with Ca and Na, indicating diagenetic changes or red-beds derived from differing source areas.