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1,862 results on '"Jensen A"'

4. Mononuclear Rhodium(III) Complexes with N,N',N'-Trimethyl-1,1,1-tris(aminomethyl)ethane (Me3-tame). Preparations, Characterization and Configurational Isomerization. Crystal Structure of meso-[Rh(Me3-tame)2](ReO4)3.1.2H2O

Author

Frode Galsbøl, Anette Frost Jensen, L. Mønsted, Kim Pilkjær Simonsen, Hayato Matsui, and Peter Andersen

Subjects
chemistry.chemical_compound, Stereochemistry, Chemistry, General Chemical Engineering, chemistry.chemical_element, Crystal structure, 1,1,1-Tris(aminomethyl)ethane, Isomerization, Medicinal chemistry, Rhodium
Published
1999

8. Cladobotryal: a Fungal Metabolite with a Novel Ring System

Author

Jens Breinholt, Helle C. Jensen, Anders Kjær, Carl E. Olsen, Birgitte R. Rassing, Connie N. Rosendahl, Inger Søtofte, and Bengt Långström

Subjects
Antifungal, Antifungal Agents, Magnetic Resonance Spectroscopy, Molecular Structure, Pyridones, medicine.drug_class, Stereochemistry, General Chemical Engineering, Fungi, Ring (chemistry), Mass Spectrometry, chemistry.chemical_compound, Fungal metabolite, X-Ray Diffraction, chemistry, medicine, Hemiacetal, Furans, Cladobotryal
Abstract

In screening for antifungal metabolites a novel compound, cladobotryal, was isolated from the mycoparasitic fungus Cladobotryum varium. Its structure was established as (+)-(2R*,3R*)-2-[(Z)-2-buten-2-yl]-3, 7-dihydro-3-formyl-3-methyl-5-phenylfuro[2,3-b]pyridin-4(2H)-one on the basis of spectroscopic evidence and single crystal X-ray analysis of its methyl hemiacetal. The fused furo[2,3-b]pyridinone skeleton of cladobotryal seems unprecedented within the chemical literature.

Published
1998

11. Bis-Intercalation of Homodimeric Thiazole Orange Dyes in Selective Binding Sites of DNA Studied by 1H NMR Spectroscopy

Author

Kurt V. Mikkelsen, Kent Bondensgaard, Charlotte H. Gotfredsen, Ingrid Fussing, Henning Lund, Lisbeth Krüger Jensen, Jens Peter Jacobsen, and Alexander Senning

Subjects
1h nmr spectroscopy, chemistry.chemical_compound, chemistry, General Chemical Engineering, Intercalation (chemistry), Nuclear magnetic resonance spectroscopy of nucleic acids, Binding site, Thiazole orange, Photochemistry, DNA
Published
1998

14. Bacterial Carotenoids 56. On the Spirilloxanthin Stereoisomeric Set

Author

Manuela Merchán, Chris M. Hartshorn, Tone-Rigmor Lindal, Synnøve Liaaen-Jensen, Bryan R. Wood, Lars Skattebøl, Ward T. Robinson, Björn O. Roos, Michael P. Hartshorn, and Claire Vallance

Subjects
Set (abstract data type), chemistry.chemical_classification, Chemistry, Stereochemistry, General Chemical Engineering, Carotenoid
Published
1997

15. Total Synthesis of C31-Methyl Ketone Apocarotenoids 3. On the Structure of Hopkinsiaxanthin: First Total Synthesis of (all-E)-(3S)- and (9Z)-(3S)-7'-Apohopkinsiaxanthin

Author

Jarle André Haugan, Emil Lobkovsky, Synnøve Liaaen-Jensen, Lars Skattebøl, and Connie N. Rosendahl

Subjects
Models, Molecular, Chromatography, Molecular Structure, medicine.diagnostic_test, Cyclohexanones, Chemistry, General Chemical Engineering, Total synthesis, Medicinal chemistry, chemistry.chemical_compound, Spectrophotometry, Bromide, Yield (chemistry), medicine, Hopkinsiaxanthin, Molecule, Computer Simulation, Methyllithium, Cis–trans isomerism
Abstract

Optically active (all-E)-(3S)-7'-apohopkinsiaxanthin, previously known as F1, and (9Z)-(3S)-7'-apohopkinsiaxanthin have been prepared by total synthesis for the first time in ca. 1% combined overall yield, including two unidentified geometrical isomers, in sixteen linear steps from (4R,6R)-actinol, (2E)-3-methyl-2-penten-4-yn-1-ol, (7-formyl-2-methyl-2,4,6-octatrienyl)triphenylphosphonium bromide, (3-formyl-2-butenyl)triphenylphosphonium bromide and methyllithium, by use of a C15 + C10 + C5 + C1 approach. By an alternative route from (2Z)-5-[((4S)-4-hydroxy-2,6,6-trimethyl-3-oxo-1-cyclohexenyl)-3- methyl-2-penten-4-ynyl]triphenylphosphonium bromide, (7-formyl-2-methyl-2,4,6-octatrienyl)triphenylphosphonium bromide and (2E)-3-methyl-4-oxo-2-pentenal, the same target compounds were obtained in a combined overall yield of > 61%, including four unidentified geometrical isomers, over two steps, by use of a C15 + C16 approach. A hypothetical structure for hopkinsiaxanthin is discussed, based on present and previously reported spectroscopic and chemical data for (all-E)-(3S)- and (9Z)-(3S)-7'-apohopkinsiaxanthin and on data previously reported for hopkinsiaxanthin itself.

Published
1997

17. Autocatalysis and the Generation of Self-Replicating Systems

Author

Georg W. Jensen, Monika Haugg, Inge L. Møller, Connie N. Rosendahl, Bernd Pilawa, Ruby I. Nielsen, Julius Rebek, Nathalie Trabesinger-Rüf, Edward A. Wintner, Elmar Weinhold, and Carl Erik Olsen

Subjects
Autocatalysis, Chemical physics, Chemistry, General Chemical Engineering
Published
1996

18. Spin Density Calculations on the Tetraphenylverdazyl Radical and Two Nitroxide Radicals: First and Second Order Spin Polarization

Author

Nathalie Trabesinger-Rüf, Georg W. Jensen, Lars Öhrström, André Grand, Carl Erik Olsen, Bernd Pilawa, Elmar Weinhold, Connie N. Rosendahl, Ruby I. Nielsen, Monika Haugg, and Inge L. Møller

Subjects
Nitroxide mediated radical polymerization, Spin polarization, Chemistry, General Chemical Engineering, Radical, Order (ring theory), Spin density, Molecular physics
Published
1996

19. Solid Phase Synthesis of Two Phosphorylated Peptides Related to Casein using Allyl Phosphate Protection, and their CD Spectra

Author

Elisabeth Larsson, Björn Lüning, Jennifer Reed, Christian Krog-Jensen, Ward T. Robinson, David J. Timmerman-Vaughan, Muhammed Nour Homsi, Frank K. H. Kuske, Monika Haugg, Nathalie Trabesinger-Rüf, and Elmar G. Weinhold

Subjects
Mesylates, chemistry.chemical_classification, Circular dichroism, Magnetic Resonance Spectroscopy, Stereochemistry, Circular Dichroism, General Chemical Engineering, Caseins, Peptide, Spectrometry, Mass, Fast Atom Bombardment, Allyl Compounds, chemistry.chemical_compound, Solid-phase synthesis, chemistry, Nucleophile, Phosphoserine, Casein, Organic chemistry, Indicators and Reagents, Spectrophotometry, Ultraviolet, Azide, Phosphorylation, Casein kinase 2, Peptides, Resins, Plant
Abstract

Phosphoserine peptides related to the casein kinase II substrate consensus sequence ESLSSSEE have been synthesized using N-Boc-O-diallylphosphono-L-serine by solid-phase methods. The allyl groups were removed, while the peptide was still attached to the solid support, by Pd0 with azide as the nucleophile. Far UV circular dichroism measurements indicate that peptides phosphorylated at Ser 4 or Ser 5 have a somewhat higher content of ordered structure than the non-phosphorylated peptide.

Published
1996

20. Using the Process of Reactive Immunization to Induce Catalytic Antibodies with Complex Mechanisms: Aldolases

Author

Richard A. Lerner, Carlos F. Barbas III, M. Jensen, E. Hedenström, H.-E. Högberg, Frode Rise, Kjell Undheim, Connie N. Rosendahl, Monika Haugg, Nathalie Trabesinger-Rüf, and Elmar G. Weinhold

Subjects
General Chemical Engineering, Molecular Conformation, Antibodies, Catalytic, chemical and pharmacologic phenomena, Antibodies, Substrate Specificity, Catalysis, Enamine, Acetone, chemistry.chemical_compound, Fructose-Bisphosphate Aldolase, Enzyme Inhibitors, chemistry.chemical_classification, Aldehydes, Binding Sites, Molecular Structure, biology, Mechanism (biology), Lysine, Aldolase A, Ketones, Combinatorial chemistry, Kinetics, Enzyme, chemistry, Immunization, Spectrophotometry, biology.protein, Imines, Antibody, Hapten
Abstract

The process of reactive immunization has been used to induce efficient aldolase catalytic antibodies that use the enamine mechanism of natural enzymes. Reactive immunogens are those that react chemically during induction of the immune response. This same reaction is used later in catalysis. In essence one immunizes with the equivalent of a mechanism-based inhibitor. The difference is that instead of inhibiting a mechanism, a mechanism is induced. This advance allows the experimenter to dictate the exact mechanism by which catalytic antibodies proceed. The hapten used in the present study is a 1,3-diketone that both traps the requisite lysine residue to initiate formation of the enamine and induces a binding pocket that overcomes the entropic barrier of this bimolecular reaction.

Published
1996

21. Polymer-Supported Tripyridylmethane Derivatives: Lewis Acid Catalyzed Ring Opening of Styrene Oxide

Author

Monika Haugg, Georg W. Jensen, Vincent Levacher, Nathalie Trabesinger-Rüf, Ruby I. Nielsen, Christina Moberg, Connie N. Rosendahl, Inge L. Møller, Elmar Weinhold, Carl Erik Olsen, and Hans Adolfsson

Subjects
chemistry.chemical_compound, Chemistry, General Chemical Engineering, Styrene oxide, Organic chemistry, Lewis acids and bases, Ring (chemistry), Polymer supported, Catalysis
Published
1996

22. Resolution of 2-Methylalkanoic Acids. Enantioselective Esterification with Long Chain Alcohols Catalysed by Candida rugosa Lipase

Author

H. Edlund, P. Berglund, M. Jensen, E. Hedenström, H.-E. Högberg, Frode Rise, Kjell Undheim, Connie N. Rosendahl, Monika Haugg, Nathalie Trabesinger-Rüf, and Elmar G. Weinhold

Subjects
Resolution (mass spectrometry), biology, Chemistry, General Chemical Engineering, biology.protein, Enantioselective synthesis, Organic chemistry, Enantiomer, Lipase, Long chain, Candida rugosa
Abstract

Candida rugosa lipase catalysed resolutions of 2-methylalkanoic acids run on a large scale often display decreased enantiomeric rations (E-values) and reaction rates compared with small-scale exper ...

Published
1996

23. Nucleophilic Reactions between Cyclic 1,2-Sulfites and Chloride Ions

Author

Muhammed Nour Homsi, Thorleif Anthonsen, Nathalie Trabesinger-Rüf, Monika Haugg, John S. Svendsen, Ryszard Gawinecki, Frank K. H. Kuske, Elmar Weinhold, Günter Häfelinger, Kirsten Nymann, and Linda Jensen

Subjects
Nucleophile, Chemistry, General Chemical Engineering, Polymer chemistry, medicine, Chloride, Ion, medicine.drug
Published
1996

26. Synthetic Selenium Carotenoids

Author

David J. Timmerman-Vaughan, Jo Klaveness, Danuta Rasała, Hans-Richard Sliwka, Per Halfdan Nielsen, Ryszard Gawinecki, Synnøve Liaaen-Jensen, and Barbara Pniewska

Subjects
chemistry.chemical_classification, chemistry, General Chemical Engineering, chemistry.chemical_element, Food science, Carotenoid, Selenium
Published
1995

28. Synthesis of 4-Quinolone Derivatives

Author

Søren Rosendal Jensen, Wim Dehaen, Kurt B. G. Torssell, Atle Aaberg, George W. Francis, Lene Krogh Christensen, Anne Gjerløv, Sine Larsen, Dagfinn W. Aksnes, Giovanni Sindona, and Anna Napoli

Subjects
medicine.drug_class, Chemistry, General Chemical Engineering, medicine, Quinolone, Combinatorial chemistry
Published
1995

30. Algal Carotenoids. 58. Isomerization Studies on Peridinin

Author

Synnøve Liaaen-Jensen, Ernst Glinz, Torunn Aakermann, Ulf Ragnarsson, George W. Francis, Gerhard Englert, Bengt Fransson, Jarle André Haugan, and Jan Balzarini

Subjects
chemistry.chemical_classification, chemistry.chemical_compound, Peridinin, chemistry, General Chemical Engineering, Photochemistry, Carotenoid, Isomerization
Published
1994

31. Malonofungin: an Antifungal Aminomalonic Acid from Phaeroamularia fusimaculans

Author

Nina Berova, Koji Nakanishi, Ruby I. Nielsen, Christian Pedersen, Anders Kjær, Jens Breinholt, Georg W. Jensen, Carl Erik Olsen, Lee-Chiang Lo, and Carsten Enggaard Stidsen

Subjects
Antifungal, Circular dichroism, Antifungal Agents, Magnetic Resonance Spectroscopy, biology, medicine.drug_class, Stereochemistry, Chemistry, Circular Dichroism, General Chemical Engineering, Molecular Conformation, Acetylation, Stereoisomerism, Growth inhibitory, Microbial Sensitivity Tests, biology.organism_classification, Malonates, Fatty Acids, Unsaturated, medicine, Proton NMR, Aminomalonic acid, Mitosporic Fungi, Botrytis cinerea, Phaeoramularia fusimaculans
Abstract

In screening for antifungal metabolites, a novel compound, malonofungin, exhibiting growth inhibitory activity against Botrytis cinerea (grey mould), has been isolated from fermentations of Phaeoramularia fusimaculans CBS 616.87. Its structure is established as (E)-(3R,4S,5S)-5-acetoxy-2-amino-2-carboxy-3,4-dihydroxy-14-oxoicos++ +-6-enoic acid, representing an addition to the rare class of naturally occurring aminomalonic acids. 1H NMR data and extensive use of CD spectroscopy have been utilized to establish the absolute stereochemistry of malonofungin. The structural and biological relationship of malonofungin to previously reported fungal metabolites is discussed.

Published
1994

32. Molecular Dynamics Simulation of Sucrose in Aqueous and Dimethyl Sulfoxide Solution

Author

Synnøve Liaaen-Jensen, Göran Widmalm, Jan Balzarini, George W. Francis, Ulf Ragnarsson, Aatto Laaksonen, Stephen Bagley, Bengt Fransson, and Michael Odelius

Subjects
chemistry.chemical_compound, Molecular dynamics, Aqueous solution, Sucrose, Chemistry, Dimethyl sulfoxide, General Chemical Engineering, Organic chemistry
Published
1994

35. Blue Carotenoids. Part 1. Novel Oxonium Ions Derived from Fucoxanthin

Author

Jarle André Haugan, Synnøve Liaaen-Jensen, Gudrun B. Paulsen, Johan Springborg, Dong-Ni Wang, Ruby I. Nielsen, Carl E. Olsen, Christian Pedersen, and Carsten E. Stidsen

Subjects
chemistry.chemical_classification, chemistry.chemical_compound, chemistry, General Chemical Engineering, Fucoxanthin, Reaction intermediate, Photochemistry, Oxonium ion, Carotenoid, Ion
Published
1994

36. Acid-Catalyzed Hydrolysis of Oxetane

Author

Jan Balzarini, George W. Francis, Aatto Laaksonen, Göran Widmalm, Synnøve Liaaen-Jensen, Ulf Ragnarsson, Juha-Matti Koskinen, Bengt Fransson, and Martti Lajunen

Subjects
chemistry.chemical_compound, Hydrolysis, Chemistry, General Chemical Engineering, Acid catalyzed, Organic chemistry, Oxetane
Published
1994

37. HPLC and NMR Investigation of the Serum Amine Oxidase Catalyzed Oxidation of Polyamines

Author

Gunnar Houen, Klaus Bock, Arne L. Jensen, Johann Weidlein, Hansgeorg Schnöckel, Gudrun B. Paulsen, Ruby I. Nielsen, Carl E. Olsen, Christian Pedersen, and Carsten E. Stidsen

Subjects
Amine oxidase, Magnetic Resonance Spectroscopy, Spermidine, General Chemical Engineering, Borohydrides, Spectrometry, Mass, Fast Atom Bombardment, Catalysis, chemistry.chemical_compound, Polyamines, Putrescine, Animals, Organic chemistry, Acrolein, Bovine serum albumin, Hydrogen peroxide, Chromatography, High Pressure Liquid, Aldehydes, Oxidoreductases Acting on CH-NH Group Donors, Propylamines, biology, Amine oxidase (copper-containing), Nuclear magnetic resonance spectroscopy, Fetal Blood, chemistry, Biochemistry, biology.protein, Cattle, Spermine, Amine gas treating, Amine Oxidase (Copper-Containing), Oxidation-Reduction
Abstract

In the presence of amine oxidases polyamines arrest cell proliferation owing to the generation of hydrogen peroxide and amino aldehydes. In this investigation the bovine serum amine oxidase catalyzed oxidation of polyamines has been studied by HPLC analysis of dansylated reaction products with or without NaBH4 reduction and by NMR spectroscopy of the reaction products and 3-aminopropanal was found to be a major reaction product. These findings were further substantiated by analysis of the reaction products by ion-exchange chromatography and by analysis of the products formed by oxidation of polyamines by the cofactor of Cu amine oxidases, 6-hydroxydopa. 3-Aminopropanal is unstable and can give rise to acrolein by beta-elimination.

Published
1994

39. Extended X-Ray Absorption Fine Structure Spectroscopic Study of Acetone Solutions of Zinc and Lead(II) Ethylxanthate

Author

Mats Valli, Per Persson, Ingmar Persson, Brian N. Figgis, Synnøve Liaaen-Jensen, Jan Balzarini, Bengt Fransson, Ulf Ragnarsson, and George W. Francis

Subjects
chemistry.chemical_compound, Nickel, chemistry, Octahedron, Extended X-ray absorption fine structure, General Chemical Engineering, Inorganic chemistry, Acetone, chemistry.chemical_element, Zinc, Inner sphere electron transfer, Absorption (chemistry), Ion
Abstract

EXAFS and vibrational spectra of acetone solutions of zinc and lead(II) ethylxanthate have been recorded in order to correlate structural data with absorption bands in the mid-infrared region. Two ethylxanthate ions are monodentately coordinated to both zinc and lead(II) in acetone solution. Two acetone molecules are weakly coordinated to zinc to complete a tetrahedral configuration round zinc, while no acetone molecules were found in the inner sphere of the lead(II) complex. A band containing a large contribution from the C-S stretching, observed just above 1000 cm(-1) in solid zinc and lead(II) ethylxanthate, where the ethylxanthate ion is bridgingly and bidentately coordinated, respectively, shifts upwards by 20 and 17 cm(-1) in the corresponding zinc and lead(II) complexes, respectively, in acetone solution. An upward shift by about 8 cm(-1) is found in the nickel(II) and arsenic(III) complexes, where the coordination of the ethylxanthate ion remains unchanged but acetone molecules solvate the central ion to complete an octahedral configuration. No shift was found in iron(III) ethylxanthate, where the coordination remains unchanged and no acetone molecules solvate the iron(III) ion. (Less)

Published
1994

40. Substituent Effects in the Rearrangement of 4-Alkyl-4H-1,2,4-triazoles

Author

Carsten E. Stidsen, Carl Erik Olsen, Per H. J. Carlsen, Georg W. Jensen, Koji Nakanishi, Anders Kjær, Ruby I. Nielsen, Odd R. Gautun, Lee-Chiang Lo, and Christian Pedersen

Subjects
chemistry.chemical_classification, chemistry.chemical_compound, chemistry, General Chemical Engineering, Substituent, Medicinal chemistry, Alkyl
Published
1994

44. Synthetic Routes to Nitroamino Precursors of the Food Carcinogen 2-Amino-1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridine and its 3-Methyl Isomer via Pd(0)-Catalysed Arylation

Author

Mikael Eriksson, Teddy K. Thorsen, Anne K. Jensen, Philip Coppens, Spiros Grivas, Ole Buchardt, and Stefan Lindström

Subjects
chemistry.chemical_classification, chemistry.chemical_compound, chemistry, Nitric acid, General Chemical Engineering, Pyridine, Nitro compound, Medicinal chemistry, Carcinogen, Catalysis
Published
1993

46. Hydrolytic Properties of the Triaqua[N,N',N'-trimethyl-1,1,1-tris(aminomethyl)ethane]chromium(III) Ion, [Cr(Me3-tame)(H2O)3]3+. Crystal Structure of [(Me3-tame)Cr(H3O2)3Cr(Me3-tame)](CF3SO3)3 with Three Short Hydrogen Bonds Connecting the Two Mononuclear Units

Author

Ulla Pretzmann, Sine Larsen, Anne K. Jensen, Teddy K. Thorsen, Ole Buchardt, Philip Coppens, and Peter Andersen

Subjects
Stereochemistry, Hydrogen bond, Chemistry, General Chemical Engineering, chemistry.chemical_element, Crystal structure, chemistry.chemical_compound, Hydrolysis, Chromium, X-ray crystallography, Polymer chemistry, Molecule, 1,1,1-Tris(aminomethyl)ethane, Trifluoromethanesulfonate
Published
1993

47. Microwave and Ab Initio Study of the Conformational Properties of 3-Furanmethanol

Author

Philip Coppens, Teddy K. Thorsen, K.-M. Marstokk, Ulf Ragnarsson, Anne K. Jensen, Harald Møllendal, and Ole Buchardt

Subjects
Bond length, Molecular geometry, Electronic correlation, Chemistry, Computational chemistry, Ab initio quantum chemistry methods, General Chemical Engineering, Ab initio, Molecule, Rotational spectroscopy, Microwave
Published
1993

48. Algal Carotenoids. 55. Structure Elucidation of (3S,5R,6R,3'S,5'R,6'S)-13'-cis-7',8'-Dihydroneoxanthin-20'-al 3'-beta-D-Lactoside (P457). Part 1. Reisolation, Derivatization and Synthesis of Model Compounds

Author

Philip Coppens, Synnøve Liaaen-Jensen, Robert R. L. Guillard, Alan C. Weedon, Evy Jørgensen, Ole Buchardt, and Torunn Aakermann

Subjects
chemistry.chemical_classification, biology, Chemistry, Stereochemistry, ved/biology, General Chemical Engineering, ved/biology.organism_classification_rank.species, Glycoside, biology.organism_classification, chemistry.chemical_compound, Algae, Amphidinium carterae, Derivatization, Carotenoid
Published
1993

49. Cooper(II) Complexes of 2-Amino-2-hydroxymethyl-1,3-propanediol. Part 2. Synthesis, Structure and Thermal Behavior of cis-[2-amino-2-hydroxymethyl-1,3-propanediol(1,3)-O,O',N][2-amino-2-hydroxymethyl-1,3-propanediolato(1-)-O,N]nitratocopper(II), [Cu(C4H10NO3)(C4H11NO3)(NO3)], and cis-[2-Amino-2-hydroxymethyl-1,3-propanediol(1,3-)-O,O',N][2-amino-2-hydroxymethyl-1,3-propanediolato(1,3-)-O,O',N]copper(II) Sodium Bis(perchlorate), [Cu(C4H10NO3)(C4H11NO3)]Na(ClO4)2

Author

Sirpa Kotila, Jussi Valkonen, Ulf Ragnarsson, Anne K. Jensen, Teddy K. Thorsen, Philip Coppens, and Ole Buchardt

Subjects
General Chemical Engineering
Published
1993

50. Rearrangement of Carbohydrate Epoxides to Acetals Using a Hemiacetal Neighbouring Group

Author

Anne K. Jensen, Steffen Jacobsen, Ole Buchardt, Ulla Pretzmann, Philip Coppens, Teddy K. Thorsen, and Frank Sløk

Subjects
chemistry.chemical_classification, chemistry.chemical_compound, chemistry, Aldose, Stereochemistry, General Chemical Engineering, Acetal, Epoxide, Chloral, Glycoside, Hemiacetal, Carbohydrate, Aldehyde
Published
1993

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