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21.
Lucija Jukić Urška Bratušek Marko Škof Jurij Svete Branko Stanovnik 《Chemistry of Heterocyclic Compounds》1996,32(11-12):1295-1299
A novel approach to the synthesis of 3-acylindolizines and the transformations of some acids into tryptophane analogues are described. Reaction of ethyl 2-pyridinylacetate and methyl 2-quinolinylacetate with N-trifluoroacetyl-5-bromo-4-oxonorvaline methylester led to N-trifluoroacetyl-3-(1-ethoxycarbonylindolizinyl-2) alanine methyl ester and N-trifluoroacetyl-3-(3-methoxycarbonylpyrrolo [1,2-a]quinolinyl-2) alanine methyl ester, respectively. Treatment of ethyl 2-pyridinylacetate and 2-pyridinylacetonitrile, first with N,N-dimethylformamide dimethyl acetal (DMFDMA), followed by reaction with phenacyl bromide, gave the corresponding 3-benzoylindolizines, while the reaction of ethyl 2-pyridinylacetate and 2-pyridinylacetonitrile with DMFDMA, followed by treatment with (S)-N-trifluoroacetyl-5-bromo-4-oxonorvaline methyl ester, gave the corresponding N-trifluoroacetyl-4-oxo-4-(indolizinyl-3)homoalanine methyl esters. 相似文献
22.
Sonja Strah Branko Stanovnik Simona Goli
Grdadolnik 《Journal of heterocyclic chemistry》1997,34(1):263-267
Alkyl 2-(2-benzoyl-2-ethoxycarbonyl-1-ethenyl)amino-3-dimethylaminopropenoates 4a,b were prepared. They react with C-nucleophiles such a 2-pyridinylacetonitrile 5 and methyl-2-quinolinylacetate 8, cyclohexane-1,3-dione 10 and its derivatives 12 and 14, resorcinol derivative 16 , 2-naphtol 18, 2-pyranone derivatives 20 and 22, and 4-hydroxypyridin-2(1H)-one 24, to form substituted amino derivatives of quinolizine 6, benzo[c]quinolizine 9, tetrahydrobenzopyran-2-one 11, 13, 15 , naphto[2,1-b]pyran-3-one 19 , pyranopyranones 21, 23, and pyrano[3,2-c]pyridine 25. 相似文献
23.
Steva Lević Nina Obradović Vladimir Pavlović Bojana Isailović Ivana Kostić Miodrag Mitrić Branko Bugarski Viktor Nedović 《Journal of Thermal Analysis and Calorimetry》2014,118(2):661-668
In this study, polyvinyl alcohol (PVA) nanofibers with ethyl vanillin as an active compound were prepared using electrospinning technique. The final products of electrospinning process were in the form of nanofibers films. PVA/ethyl vanillin nanofibers, having fibers diameters in the range 100–1700 nm, were successfully electrospun from ethanol/water mixture of PVA and ethyl vanillin. The effects of immobilization process on ethyl vanillin thermal properties were investigated by differential scanning calorimetry (DSC). The results of DSC showed significant influence of immobilization process on thermal properties of ethyl vanillin. It was noticed that melting point of immobilized ethyl vanillin was lower (~55 °C) compared to free flavor (~77 °C). Our results showed that films based on PVA/ethyl vanillin nanofibers are mechanically stable. 相似文献
24.
25.
Branko Druzina Matej Stegu 《International journal of environmental analytical chemistry》2013,93(15):1079-1093
The degradation of 15 organophosphorus insecticides was studied in drinking, ground, and surface waters under different laboratory-controlled and environmental conditions. Surface waters originated from rivers Savinja (near the city of Celje) and Kamniska Bistrica (at the spring), which both belong to the Danube river basin. Groundwater was collected from wells (70?m deep) in Ljubljana, which are the direct source of drinking water for the capital. These matrices were selected on the basis of their different chemical composition and microbial activity. Major factors influencing the degradation were determined, such as temperature, oxygen, sunlight, pH, and type of water. The degradation of atrazine, present in many water sources in Slovenija, was followed simultaneously as a reference under the same conditions. The degradation kinetics was followed by gas chromatography with mass-selective detection, which also allowed the identification of some degradation by-products, such as oxon analogues paraoxon, dyfoxon, malaoxon, phenyl-methyl sulfoxide, fenthion sulfone, phorate sulfoxide, and phorate sulfone. The results show that the half-lives of the selected organophosphorus insecticides varied from 4 to 192 days or more, depending on the water source and experimental conditions. As a result, kinetically constants and half-lives were calculated for every tested insecticide, and major degradation products were determined. 相似文献
26.
A simple synthetic procedure for direct formamidation and amination of aryl halides mediated by copper(II) salts was developed in open air, without an external ligand in formamide with potassium carbonate as a base. This approach is particularly efficient when electron active aryl halides are used as substrates. In these cases almost quantitative formamidation was observed. 相似文献
27.
Benjamin Prek Jure Bezenšek Marta Kasunič Uroš Grošelj Jurij Svete Branko Stanovnik 《Tetrahedron》2014
Herein a simple one-pot metal-free synthesis of alkyl-, aryl-, heteroaryl- and alkoxycarbonyl substituted 1,3-bis(dimethylamino)benzene derivatives is described. The products were prepared from the corresponding methyl ketones or compounds with an α-methylene group in regard to the carbonyl group, using N,N-dimethylacetamide dimethyl acetal (DMADMA) as the reagent. 相似文献
28.
Miha Drev Uroš Grošelj Špela Mevec Eva Pušavec Janja Štrekelj Amalija Golobič Georg Dahmann Branko Stanovnik Jurij Svete 《Tetrahedron》2014
The synthesis of 7-substituted pyrazolo[1,5-a]pyrimidine-3-carboxamides was studied. First, methyl 7-hydroxypyrazolo[1,5-a]pyrimidine-3-carboxylate (5) was prepared in three steps from methyl 5-amino-1H-pyrazole-4-carboxylate (3). Treatment of 5 with POCl3 gave the highly reactive 7-chloro derivative 10, which was reacted with amines, benzyl alcohol, and phenylboronic acid in the presence of Pd-catalyst to give the corresponding 7-substituted derivatives 11. Hydrolysis of the esters 5 and 11 followed by amidation gave the corresponding carboxamides 16a–h and 15. Regioselectivity of N-alkylation of 7-hydroxypyrazolo[1,5-a]pyrimidine-3-carboxylic acid derivatives 5 and 16 was tunable by the carboxy function. Alkylation of the secondary amides 16a–f furnished the 1-alkyl derivatives 17a–f, whereas the ester 5 and the tertiary amides 16g,h gave the 4-alkyl derivatives 14a–d and 16m,n, selectively. 相似文献
29.
Akai Takashi Alhammadi Amer M. Blunt Martin J. Bijeljic Branko 《Transport in Porous Media》2019,130(3):731-749
Transport in Porous Media - We demonstrate how to use numerical simulation models directly on micro-CT images to understand the impact of several enhanced oil recovery (EOR) methods on microscopic... 相似文献
30.
The methylation of some pyrazolin-5-ones with dimethyl sulfate in different reaction conditions is described, ft is found that it is possible achived selective introducing of methyl group in desired position of pyrazolin-5-one ring which is of great interest for preparation of many analgesics and antipyretics with pyrazolin-5-one unit. 相似文献