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  • 51.
    Angles d'Ortoli, Thibault
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Hamark, Christoffer
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Structure-Reactivity Relationships of Conformationally Armed Disaccharide Donors and Their Use in the Synthesis of a Hexasaccharide Related to the Capsular Polysaccharide from Streptococcus pneumoniae Type 372017Inngår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 82, nr 15, s. 8123-8140Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To advance the field of glycobiology, efficient synthesis methods of oligosaccharides and glycoconjugates are a requisite. In glycosylation reactions using superarmed donors, both selectivity and reactivity issues must be considered, and we herein investigate these aspects for differently protected beta-linked 2-O-glycosylated glucosyl donors carrying bulky tert-butyldimethylsilyl groups to different extents. The acceptors in reactions being secondary alcohols presents a challenging situation with respect to steric crowding. Conformational pyranose ring equilibria of the superarmed disaccharide donors with axial-rich substituents contained skew and boat conformations, and three-state models were generally assumed. With NIS/TfOH as the promotor, 2,6-di-tert-butyl-4-methylpyridine as the base, and a dichloromethane/toluene solvent mixture, ethyl 1-thio-beta-d-glucosyl disaccharide donors having 6-O-benzyl group(s) besides tert-butyldimethylsilyl groups were efficiently coupled at -40 degrees C to the hydroxyl group at position 3 of glucopyranosyl acceptors to form beta-(1 -> 2),beta-(1 -> 3)-linked trisaccharides, isolated in excellent 95% yield. The more axial-rich donors in skew and boat conformations are thus preorganized closer to the assumed transition state in these glycosylation reactions. The developed methodology was subsequently applied in the synthesis of a multibranched hexasaccharide related to the capsular polysaccharide from Streptococcus pneumoniae type 37, which consists of a beta-(1 -> 3)-linked backbone and a beta-(1 -> 2)-linked side chain of D-glucosyl residues in disaccharide repeating units.

  • 52.
    Angles d'Ortoli, Thibault
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sjöberg, Nils A.
    Vasiljeva, Polina
    Lindman, Jonas
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bergenstråhle-Wohlert, Malin
    Wohlert, Jakob
    Temperature Dependence of Hydroxymethyl Group Rotamer Populations in Cellooligomers2015Inngår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 119, nr 30, s. 9559-9570Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Empirical force fields for computer simulations of carbohydrates are often implicitly assumed to be valid also at temperatures different from room temperature for which they were optimited: Herein, the temperature dependence of the hydroxymethyl group rotamer populations in short oligogaccharides is invegtigated using Molecular dynamics simulations and NMR spectroscopy. Two oligosaccharides, methyl beta-cellobioside and beta-cellotetraose were simulated using three different carbohydrate force fields (CHARMM C35, GLYCAM06, and GROMOS 56A(carbo)) in combination with different water models (SPC, SPC/E, and TIP3P) using replica exchange molecular dynamics simulations. For comparison, hydroxymethyl group rotamer populations were investigated for methyl beta-cellobioside and cellopentaose based- on measured NMR (3)J(H5,H6) coupling constants, in the latter case by using a chemical shift selective NMR-filter. Molecular dynamics simulations in combination with NMR spectroscopy show that the temperature dependence of the hydroxymethyl rotamer population in these short cellooligomers, in the range 263-344 K, generally becomes exaggerated in simulations when compared to experimental data, but also that it is dependent on simulation conditions, and most notably properties of the water model.

  • 53.
    Angles d'Ortoli, Thibault
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthesis of the tetrasaccharide glycoside moiety of Solaradixine and rapid NMR-based structure verification using the program CASPER2016Inngår i: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 72, nr 7, s. 912-927Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The major glycoalkaloid in the roots of Solanum laciniatum is Solaradixine having the branched tetrasaccharide beta-D-Glcp-(1 -> 2)-beta-D-Glcp-(1 -> 3)[alpha-L-Rhap-(1 -> 2)]-beta-D-Galp linked to O3 of the steroidal alkaloid Solasodine. We herein describe the synthesis of the methyl glycoside of the tetrasaccharide using a super-armed disaccharide as a donor molecule. A 2-(naphthyl)methyl protecting group was used in the synthesis of the donor since it was tolerant to a wide range of reaction conditions. The 6-O-benzylated-hexa-O-tert-butyldimethylsilyi-protected beta-D-Glcp-(1 -> 2)-beta-D-Glcp-SEt donor, which avoided 1,6-anydro formation, was successfully glycosylated at O3 of a galactoside acceptor molecule. However, subsequent glycosylation at O2 by a rhamnosyl donor was unsuccessful and instead a suitably protected alpha-L-Rhap(1 -> 2)-beta-D-Galp-OMe disaccharide was used as the acceptor molecule together with a super-armed beta-D-Glcp-(1 -> 2)-beta-D-Glcp-SEt donor in the glycosylation reaction, to give a tetrasaccharide in a yield of 55%, which after deprotection resulted in the target molecule, the structure of which was verified by the NMR chemical shift prediction program CASPER.

  • 54.
    Arafa, Wael A. A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lee, Bao-Lin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liao, Rong-Zhen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Berends, Hans-Martin
    Messinger, Johannes
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dinuclear manganese complexes for water oxidation: evaluation of electronic effects and catalytic activity2014Inngår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, nr 24, s. 11950-11964Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    During recent years significant progress has been made towards the realization of a sustainable and carbon-neutral energy economy. One promising approach is photochemical splitting of H2O into O-2 and solar fuels, such as H-2. However, the bottleneck in such artificial photosynthetic schemes is the H2O oxidation half reaction where more efficient catalysts are required that lower the kinetic barrier for this process. In particular catalysts based on earth-abundant metals are highly attractive compared to catalysts comprised of noble metals. We have now synthesized a library of dinuclear Mn-2 (II,III) catalysts for H2O oxidation and studied how the incorporation of different substituents affected the electronics and catalytic efficiency. It was found that the incorporation of a distal carboxyl group into the ligand scaffold resulted in a catalyst with increased catalytic activity, most likely because of the fact that the distal group is able to promote proton-coupled electron transfer (PCET) from the high-valent Mn species, thus facilitating O-O bond formation.

  • 55. Arafa, Wael A. A.
    et al.
    Mohamed, Ashraf M.
    Abdel-Magied, Ahmed F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    ULTRASOUND-MEDIATED THREE-COMPONENT REACTION ON-WATER PROTOCOL FOR THE SYNTHESIS OF NOVEL MONO- AND BIS-1,3-THIAZIN-4-ONE DERIVATIVES2017Inngår i: Heterocycles, ISSN 0385-5414, E-ISSN 1881-0942, Vol. 94, nr 8, s. 1439-1455Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Green synthetic and catalyst-free strategy towards the synthesis of novel mono- and bis-1,3-thiazin-4-one scaffolds through a one pot, reaction of carbon disulfide, monoacetylenic esters and amines under ultrasonication has been reported. The merits of this protocol comprise no need for tedious workup steps and afforded the desired products in excellent yields make this synthetic protocol more efficient and worthy of further attentiveness. Moreover, the method exhibited excellent score in a number of green metrics.

  • 56. Arafa, Wael Abdelgayed Ahmed
    et al.
    Abdel-Magied, Ahmed Fawzy
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Nuclear Material Authority, Egypt.
    Utilization of ultrasonic irradiation as green and effective one-pot protocol to prepare a novel series of bis-2-amino-1,3,4-oxa(thia) diazoles and bis-tetrazoles2017Inngår i: ARKIVOC, ISSN 1551-7004, E-ISSN 1551-7012, s. 327-340Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In an effective and straightforward conversion, bis-semicarbazones and bis-thiosemicarbazones are transformed into a diversity of novel substituted bis-2-amino-1,3,4-oxadiazoles and bis-2-amino-1,3,4-thiadiazoles, respectively under ultrasonic irradiation. Bis-tetrazoles are obtained from the dialdehydes by sequential reaction with hydroxylamine hydrochloride, phosphorus pentoxide and sodium azide without isolation of the intermediates oximes and nitriles. All the reactions proceed cleanly and smoothly under mild conditions, with short reaction times and broad functional groups possibility. No side reactions were observed. [GRAPHICS]

  • 57. Arewång, Carl Johan
    et al.
    Lahmann, Martina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Oscarson, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tidén, Anna-Karin
    Synthesis of urine drug metabolites: glucuronic acid glycosides of phenol intermediates2007Inngår i: Carbohydrate Research, ISSN 0008-6215, Vol. 342, nr 7, s. 970-974Artikkel i tidsskrift (Fagfellevurdert)
  • 58. Ashour, Radwa M.
    et al.
    Abdel-Magied, Ahmed F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Nuclear Materials Authority, Egypt.
    Abdel-Khalek, Ahmed A.
    Helaly, O. S.
    Ali, M. M.
    Preparation and characterization of magnetic iron oxide nanoparticles functionalized by L-cysteine: Adsorption and desorption behavior for rare earth metal ions2016Inngår i: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 4, nr 3, s. 3114-3121Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, magnetic iron oxide nanoparticles functionalized with L-cysteine (Cys-Fe3O4 NPs) was synthesized and fully characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infra-red (FTIR), thermogravimetric analysis (TGA) and zeta potential measurements. The synthesized Cys-Fe(3)O(4)NPs has been evaluated as a highly adsorbent for the adsorption of a mixture of four rare earths RE3+ ions (La3+, Nd3+, Gd3+ and Y3+) from digested monazite solutions. The influence of various factors on the adsorption efficiency such as, the contact time, sample pH, temperature, and concentration of the stripping solution were investigated. The results indicate that Cys-Fe3O4 NPs achieve high removal efficiency 96.7, 99.3, 96.5 and 87% for La3+, Nd3+, Gd3+ and Y3+ ions, respectively, at pH = 6 within 15 min, and the adsorbent affinity for metal ions was found to be in order of Nd3+ > La3+ > Gd3+ > Y3+ ions. Using the Langmuir model, a maximum adsorption capacity of La3+, Nd3+, Gd3+ and Y3+ at room temperature was found to be 71.5, 145.5, 64.5 and 13.6 mg g (1), respectively. The Langmuir isotherm and pseudo-second order model fitted much better than the other isotherms and kinetic models. The obtained results for the thermodynamic parameters confirmed the spontaneous and endothermic nature of the process. Moreover, the desorption was carried out with 0.1 M nitric acid solutions. In addition, Cys-Fe3O4 NPs can be used as a highly efficient adsorbent for the adsorption of La3+, Nd3+, Gd3+ and Y3+ ions from digested monazite solutions.

  • 59.
    Aydin, Juhanes
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Conrad, Cathrin S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Stereoselective pincer-complex catalyzed C-H functionalization of benzyl nitriles under mild conditions. An efficient route to β-aminonitriles2008Inngår i: Organic Letters, ISSN 1523-7060, Vol. 10, nr 22, s. 5175-5178Artikkel i tidsskrift (Fagfellevurdert)
  • 60.
    Aydin, Juhanes
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kumar, K. Senthil
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Palladium pincer complex-catalyzed condensation of sulfonimines and isocyanoacetate to imidazoline derivatives. Dependence of the stereoselectivity on the ligand effects2007Inngår i: Advanced Synthesis & Catalysis, ISSN 1615-4150, Vol. 349, nr 17-18, s. 2585-2594Artikkel i tidsskrift (Fagfellevurdert)
  • 61.
    Aydin, Juhanes
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kumar, K. Senthil
    Sayah, Mahmoud J.
    Wallner, Olov A.
    Szabó, Kálmán J.
    Synthesis and Catalytic Application of Chiral 1,1‘-Bi-2-naphthol- and Biphenanthrol-Based Pincer Complexes: Selective Allylation of Sulfonimines with Allyl Stannane and Allyl Trifluoroborate2007Inngår i: The Journal of Organic Chemistry, ISSN 0022-3263, Vol. 72, nr 13, s. 4689-4697Artikkel i tidsskrift (Fagfellevurdert)
  • 62.
    Aydin, Juhanes
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Larsson, Johanna M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Selander, Nicklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Pincer complex-catalyzed redox coupling of alkenes with iodonium salts via presumed palladium(IV) intermediates2009Inngår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 11, nr 13, s. 2852-2854Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Palladium pincer complexes directly catalyze the redox coupling reactions of functionalized alkenes and iodonium salts. The catalytic process, which is suitable for mild catalytic functionalization of allylic acetates and electron-rich alkenes, probably occurs through Pd(IV) intermediates. Due to the strong metal−ligand interactions, the oxidation of phosphine and amine ligands of the pincer complexes can be avoided in the presented reactions.

  • 63.
    Aydin, Juhanes
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Larsson, Johanna M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Pincer Complex-Catalyzed Coupling Reactions via Palladium (IV) Intermediates2009Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 11, nr 13, s. 2852-2854Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Palladium pincer complexes directly catalyze the redox coupling reactions of functionalized alkenes and iodonium salts. The catalytic process, which is suitable for mild catalytic functionalization of allylic acetates and electron-rich alkenes, probably occurs through Pd(IV) intermediates. Due to the strong metal−ligand interactions, the oxidation of phosphine and amine ligands of the pincer complexes can be avoided in the presented reactions.

  • 64.
    Aydin, Juhanes
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rydén, Andreas
    Szabó, Kálmán J.
    Chiral palladium-pincer complex catalyzed asymmetric condensation of sulfonimines and isocyanoacetate2008Inngår i: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 19, nr 15, s. 1867-1870Artikkel i tidsskrift (Fagfellevurdert)
  • 65.
    Aydin, Juhanes
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Selander, Nicklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Strategies for fine-tuning the catalytic activity of pincer-complexes2006Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 47, nr 50, s. 8999-9001Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Various methoxy substituted pincer-complexes were prepared in order to study the substituent effects on the catalytic activity in palladium catalyzed opening of vinyl epoxides and boronation of cinnamyl alcohol. The results clearly show that methoxy substitution at the para-position of the pincer-complex leads to up to fourfold acceleration of the catalytic reactions, while substitution of the side-arms does not change the activity of the complex or leads to a slight deceleration of the catalytic processes.

  • 66.
    Aydin, Juhanes
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Senthil, Kumar K
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sayah, Mahmoud J
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Wallner, Olov A
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J
    Synthesis and catalytic application of chiral 1,1'-Bi-2-naphthol- and biphenanthrol-based pincer complexes: selective allylation of sulfonimines with allyl stannane and allyl trifluoroborate.2007Inngår i: Journal of Organic Chemistry, Vol. 72, nr 13, s. 4689-4697Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    New easily accessible 1,1'-bi-2-naphthol- (BINOL-) and biphenanthrol-based chiral pincer complex catalysts were prepared for selective (up to 85% enantiomeric excess) allylation of sulfonimines. The chiral pincer complexes were prepared by a flexible modular approach allowing an efficient tuning of the selectivity of the catalysts. By employment of the different enantiomeric forms of the catalysts, both enantiomers of the homoallylic amines could be selectively obtained. Both allyl stannanes and allyl trifluoroborates can be employed as allyl sources in the reactions. The biphenanthrol-based complexes gave higher selectivity than the substituted BINOL-based analogues, probably because of the well-shaped chiral pocket generated by employment of the biphenanthrol complexes. The enantioselective allylation of sulfonimines presented in this study has important implications for the mechanism given for the pincer complex-catalyzed allylation reactions, confirming that this process takes place without involvement of palladium(0) species.

  • 67.
    Aydin, Juhanes
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Palladium-pincer complex catalyzed C-C coupling of allyl nitriles with tosyl imines via regioselective allylic C-H bond functionalization2008Inngår i: Organic Letters, ISSN 1523-7060, Vol. 10, nr 13, s. 2881-2884Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A mechanistically new palladium-pincer complex catalyzed allylation of sulfonimines is presented. This reaction involves C-H bond functionalization of allyl nitriles under mild conditions. The reaction proceeds with a high regioselectivity, without allyl rearrangement of the product. Modeling studies indicate that the carbon-carbon bond formation process proceeds via (η1-allyl)palladium pincer complex intermediates.

  • 68.
    Ayesa, Susana
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Argyopoulus, Dimitris
    Maltseva, Tatiana
    Sund, Christian
    Samuelsson, Bertil
    An Expeditious Library Synthesis of N-Monoalkylated Aminopiperidines and –pyrrolidines2004Inngår i: European Journal of Organic Chemistry, ISSN 1434-193x, nr 12, s. 2723-2737Artikkel i tidsskrift (Fagfellevurdert)
  • 69.
    Ayesa, Susana
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Chen, Jing-May
    Classon, Björn
    Gallego, Jose
    Grabowska, Urszula
    Henderson, Ian
    Heyer, Narinder
    Johnson, Tony
    Kangasmetsä, Jussi
    Liley, Mark
    Nilsson, Magnus
    Parkes, Kevin
    Rakos, Laszlo
    Tozer, Matthew J.
    Wilson, Michelle
    Preparation and Characterization of Aminoethylamide Inhibitors of the Cysteine Proteinase Cathepsin KInngår i: European Journal of Medicinal Chemistry, ISSN 0223-5234Artikkel i tidsskrift (Fagfellevurdert)
  • 70.
    Ayesa, Susana
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lindquist, Charlotta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Agback, Tatiana
    Benkestock, Kurt
    Classon, Björn
    Henderson, Ian
    Hewitt, Ellen
    Jansson, Katarina
    Kallin, Anders
    Sheppard, Dave
    Samuelsson, Bertil
    Solid-phase parallel synthesis and SAR of 4-amidofuran-3-one inhibitors of cathepsin S: Effect of sulfonamides P3 substituents on potency and selectivity.2009Inngår i: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, E-ISSN 1464-3391, Vol. 17, nr 3, s. 1307-1324Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Highly potent and selective 4-amidofuran-3-one inhibitors of cathepsin S are described. The synthesis and structure–activity relationship of a series of inhibitors with a sulfonamide moiety in the P3 position is presented. Several members of the series show sub-nanomolar inhibition of the target enzyme as well as an excellent selectivity profile and good cellular potency. Molecular modeling of the most interesting inhibitors describes interactions in the extended S3 pocket and explains the observed selectivity towards cathepsin K.

  • 71.
    Ayesa, Susana
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Samuelsson, Bertil
    Classon, Björn
    A One-Pot, Solid-Phase Synthesis of Secondary Amines from Reactive Alkyl Halides and an Alkyl Azide2008Inngår i: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, nr 1, s. 77-79Artikkel i tidsskrift (Fagfellevurdert)
  • 72.
    Babu, Beneesh P.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Endo, Yoshinori
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Biomimetic Aerobic Oxidation of Amino Alcohols to Lactams2012Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, nr 37, s. 11524-11527Artikkel i tidsskrift (Fagfellevurdert)
  • 73.
    Babu, Beneesh P.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Meng, Xu
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Aerobic Oxidative Coupling of Arenes and Olefins through a Biomimetic Approach2013Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 19, nr 13, s. 4140-4145Artikkel i tidsskrift (Fagfellevurdert)
  • 74. Back, Marcus
    et al.
    Nyhlen, Jonas
    Kvarnstrom, Ingemar
    Appelgren, Sara
    Borkakoti, Neera
    Jansson, Katarina
    Lindberg, Jimmy
    Nystrom, Susanne
    Hallberg, Anders
    Rosenquist, Asa
    Samuelsson, Bertil
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Design, synthesis and SAR of potent statine-based BACE-1 inhibitors: Exploration of P1 phenoxy and benzyloxy residues2008Inngår i: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, E-ISSN 1464-3391, Vol. 16, nr 21, s. 9471-9486Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Several BACE-1 inhibitors with low nanomolar level activities, encompassing a statine-based core structure with phenyloxymethyl- and benzyloxymethyl residues in the P1 position, are presented. The novel P1 modi. cation introduced to allow the facile exploration of the S1 binding pocket of BACE-1, delivered highly promising inhibitors.

  • 75.
    Bacsik, Zoltan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Ahlsten, Nanna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ziadi, Asraa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhao, Guoying
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Garcia-Bennett, Alfonso E.
    Uppsala universitet.
    Martin-Matute, Belen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Hedin, Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Mechanisms and Kinetics for Sorption of CO(2) on Bicontinuous Mesoporous Silica Modified with n-Propylamine2011Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 27, nr 17, s. 11118-11128Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We studied equilibrium adsorption and uptake kinetics and identified molecular species that formed during sorption of carbon dioxide on amine-modified silica. Bicontinuous silicas (AMS-6 and MCM-48) were postsynthetically modified with (3-aminopropyl)triethoxysilane or (3-aminopropyl)methyldiethoxysilane, and amine-modified AMS-6 adsorbed more CO(2) than did amine-modified MCM-48. By in situ FTIR spectroscopy, we showed that the amine groups reacted with CO(2) and formed ammonium carbamate ion pairs as well as carbamic acids under both dry and moist conditions. The carbamic acid was stabilized by hydrogen bonds, and ammonium carbamate ion pairs formed preferably on sorbents with high densities of amine groups. Under dry conditions, silylpropylcarbamate formed, slowly, by condensing carbamic acid and silanol groups. The ratio of ammonium carbamate ion pairs to silylpropylcarbamate was higher for samples with high amine contents than samples with low amine contents. Bicarbonates or carbonates did not form under dry or moist conditions. The uptake of CO(2) was enhanced in the presence of water, which was rationalized by the observed release of additional amine groups under these conditions and related formation of ammonium carbamate ion pairs. Distinct evidence for a fourth and irreversibly formed moiety was observed under sorption of CO(2) under dry conditions. Significant amounts of physisorbed, linear CO(2) were detected at relatively high partial pressures of CO(2), such that they could adsorb only after the reactive amine groups were consumed.

  • 76.
    Balan, Daniela
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Chiral quinuclidine-based amine catalysts for the asymmetric one-pot, three-component aza-Baylis–Hillman reaction2003Inngår i: Tetrahedron Letters, Vol. 44, nr 12, s. 2521-2524Artikkel i tidsskrift (Fagfellevurdert)
  • 77.
    Balan, Daniela
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Efficient microwave-assisted formation of functionalized 2,5-dihydropyrroles using ruthenium-catalyzed ring-closing metathesis2004Inngår i: Tetrahedron Letters, Vol. 45, nr 15, s. 3089-3092Artikkel i tidsskrift (Fagfellevurdert)
  • 78.
    Balan, Daniela
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Selective formation of α-methylene-β-amino acid derivatives through the aza version of the baylis-Hillman reaction2001Inngår i: The Journal of Organic Chemistry, Vol. 66, s. 6498-6501Artikkel i tidsskrift (Fagfellevurdert)
  • 79.
    Balan, Daniela
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Titanium isopropoxide as Efficient Catalyst for the aza-Baylis-Hillman reaction. Selective formation of α-methylene-β-amino acid derivatives2002Inngår i: The Journal of Organic Chemistry, Vol. 67, s. 2329-2334Artikkel i tidsskrift (Fagfellevurdert)
  • 80. Barbion, Julien
    et al.
    Sorin, Geoffroy
    Selkti, Mohamed
    Kellenberger, Esther
    Baati, Rachid
    Santoro, Stefano
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Himo, Fahmi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Pancrazi, Ange
    Lannou, Marie-Isabelle
    Ardisson, Janick
    Stereoselective functionalization of pyrrolidinone moiety towards the synthesis of salinosporamide A2012Inngår i: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 68, nr 32, s. 6504-6512Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An important feature of the synthesis of salinosporamide A. a potent proteasome inhibitor, is the establishment of the quaternary stereocenter at C3. A new route has been developed based on the methylation of a functionalized pyrrolidinone. Direct methylation reaction led to the unwanted diastereomer: however, by means of a Corey-Chaykovsky reaction followed by LiAlH4 epoxide opening, the desired alcohol was obtained. The pyrrolidinone was elaborated through a key allylation reaction between a tertiary allyltitanium reagent and an aldehyde bearing a spiroketal moiety in alpha-position.

  • 81.
    Bartholomeyzik, Teresa
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Mazuela, Javier
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Pendrill, Robert
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Deng, Youqian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Palladium-Catalyzed Oxidative Arylating Carbocyclization of Allenynes: Control of Selectivity and Role of H2O2014Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 53, nr 33, s. 8696-8699Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Highly selective protocols for the carbocyclization/arylation of allenynes using arylboronic acids are reported. Arylated vinylallenes are obtained with the use of BF3 center dot Et2O as an additive, whereas addition of water leads to arylated trienes. These conditions provide the respective products with excellent selectivities (generally > 97:3) for a range of boronic acids and different allenynes. It has been revealed that water plays a crucial role for the product distribution.

  • 82.
    Bartholomeyzik, Teresa
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Pendrill, Robert
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lihammar, Richard
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Jiang, Tuo
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kinetics and Mechanism of the Palladium-Catalyzed Oxidative Arylating Carbocyclization of Allenynes2018Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 140, nr 1, s. 298-309Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pd-catalyzed C-C bond-forming reactions under oxidative conditions constitute a class of important and widely used synthetic protocols. This Article describes a mechanistic investigation of the arylating carbocyclization of allenynes using boronic acids and focuses on the correlation between reaction conditions and product selectivity. Isotope effects confirm that either allenic or propargylic C-H activation occurs directly after substrate binding. With an excess of H2O, a triene product is selectively formed via allenic C-H activation. The latter C-H activation was found to be turnover-limiting and the reaction zeroth order in reactants as well as the oxidant. A dominant feature is continuous catalyst activation, which was shown to occur even in the absence of substrate. Smaller amounts of H2O lead to mixtures of triene and vinylallene products, where the latter is formed via propargylic C-H activation. The formation of triene occurs only in the presence of ArB(OH)(2). Vinylallene, on the other hand, was shown to be formed by consumption of (ArBO)(3) as a first-order reactant. Conditions with sub-stoichiometric BF3 center dot OEt2 gave selectively the vinylallene product, and the reaction is first order in PhB(OH)(2). Both C-H activation and transmetalation influence the reaction rate. However, with electron-deficient ArB(OH)(2), C-H activation is turnover-limiting. It was difficult to establish the order of transmetalation vs C-H activation with certainty, but the results suggest that BF3 center dot OEt2 promotes an early transmetalation. The catalytically active species were found to be dependent on the reaction conditions, and H2O is a crucial parameter in the control of selectivity.

  • 83.
    Bartoszewicz, Agnieszka
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    González Miera, Greco
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Marcos, Rocio
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Norrby, Per-Ola
    Martín-Matute, Belén
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Mechanistic Studies on the Alkylation of Amines with Alcohols Catalyzed by a Bifunctional Iridium Complex2015Inngår i: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 5, nr 6, s. 3704-3716Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The mechanism of the N-alkylation of amines with alcohols catalyzed by an iridium complex containing an N-heterocyclic carbene (NHC) ligand with a tethered alcohol/alkoxide functionality was investigated by a combination of experimental and computational methods. The catalyst resting state is an iridium hydride species containing the amine substrate as a ligand, and decoordination of the amine, followed by coordination of the imine intermediate to the iridium center, constitute the rate-determining step (rds) of the catalytic process. The alcohol/alkoxide that is tethered to the NHC participates in every step of the catalytic cycle by accepting or releasing protons and forming hydrogen bonds with the reacting species. Thus, the iridium complex with the alcohol/alkoxide tethered to the N-heterocyclic carbene ligand acts as a bifunctional catalyst.

  • 84.
    Bartoszewicz, Agnieszka
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Jezowska, Martina M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Laymand, Kevin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Mobus, Juri
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Martín-Matute, Belén
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthesis of β-Hydroxy and β-Amino Ketones from Allylic Alcohols Catalyzed by Ru(η5-C5Ph5)(CO)2Cl2012Inngår i: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, nr 9, s. 1517-1530Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An efficient method for the synthesis of beta-hydroxy and beta-amino ketones from allylic alcohols catalyzed by Ru(5-C5Ph5)(CO)2Cl is described. The influence of the stereoelectronic properties of the catalyst on the reaction outcome has been studied. Optimization of the reaction conditions supressed the formation of undesired side products such as saturated ketones, benzyl alcohols, and a,beta-unsaturated ketones. Several aromatic and aliphatic allylic alcohols have been reacted with a large variety of aldehydes or imines to produce beta-hydroxy ketones or beta-amino ketones, respectively, in yields up to 99%. Based on experimental data, a mechanism via ruthenium alkoxides and ruthenium aldoxides is proposed. In addition, a C-bound ruthenium enolate has been characterized.

  • 85.
    Bartoszewicz, Agnieszka
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kalek, Marcin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Stawinski, Jacek
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Iodine-promoted silylation of alcohols with silyl chlorides. Synthetic and mechanistic studies2008Inngår i: Tetrahedron, ISSN 0040-4020, Vol. 64, nr 37, s. 8843-8850Artikkel i tidsskrift (Fagfellevurdert)
  • 86.
    Bartoszewicz, Agnieszka
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kalek, Marcin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Stawinski, Jacek
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    The case for the intermediacy of monomeric metaphosphate analogues during oxidation of H-phosphonothioate, H-phosphonodithioate, and H-phosphonoselenoate monoesters: mechanistic and synthetic studies2008Inngår i: The Journal of Organic Chemistry, ISSN 0022-3263, Vol. 73, nr 13, s. 5029-5038Artikkel i tidsskrift (Fagfellevurdert)
  • 87.
    Bartoszewicz, Agnieszka
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Livendahl, Madeleine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Martín-Matute, Belén
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Efficient synthesis of beta-hydroxy ketones from allylic alcohols by catalytic formation of ruthenium enolates2008Inngår i: Chemistry: a European Journal, ISSN 0947-6539, Vol. 14, nr 34, s. 10547-10550Artikkel i tidsskrift (Fagfellevurdert)
  • 88.
    Bartoszewicz, Agnieszka
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Livendahl, Madeleine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Martín-Matute, Belén
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthesis of b-Hydroxy Ketones from Allylic Alcohols via Catalytic Formation of Ruthenium Enolates2008Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 14, nr 34, s. 10547-10550Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The most efficient Ru-catalyzed isomerization–aldol reaction from allylic alcohols has been achieved by using [η5-(Ph5Cp)Ru(CO)2Cl] as the catalyst. The bulky pentaphenylcyclopentadienyl ligand on the ruthenium atom prevents protonation at the oxygen of the Ru–enolate intermediate and completely suppresses the formation of unwanted ketone byproducts (see scheme). The domino transformation is as good as it can be: aldols are obtained in quantitative yields at ambient temperature.

  • 89.
    Bartoszewicz, Agnieszka
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Martín-Matute, Belén
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Building molecular complexity via tandem Ru-catalyzed isomerization/C-H activation2009Inngår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 11, nr 8, s. 1749-1752Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A tandem isomerization/C-H activation of allylic alcohols was performed using a catalytic amount of RUCl(2)(PPh(3))(3). A variety of ortho alkylated ketones have been obtained in excellent yields. This tandem process relies on an in situ generation of a carbonyl functional group that directs the ortho C-H bond activation.

  • 90. Battistel, Marcos D.
    et al.
    Pendrill, Robert
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Freedberg, Daron I.
    Direct Evidence for Hydrogen Bonding in Glycans: A Combined NMR and Molecular Dynamics Study2013Inngår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 117, nr 17, s. 4860-4869Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We introduce the abundant hydroxyl groups of glycans as NMR handle's and structural probes to expand the repertoire of tools for structure function studies on glycans in solution. To this end, we present the facile detection and assignment of hydroxyl groups in a Wide range of sample concentrations (0.5-1700 mM) and temperatures, ranging from -5 to 25 degrees C.,We then exploit this information to directly detect hydrogen bonds, well-known for their importance in molecular structural determination through NMR. Via HSQC-TOCSY, we were able to determine the directionality; of these hydrogen bonds in sucrose Furthermore, by means Of molecular dynamics simulations in conjunction with NMR, we establish that one Out of the three detected hydrogen bonds arises from intermolecular interactions. This finding may shed light on glycan glycan interactions and glycan recognition by proteins.

  • 91. Bejhed, Rebecca S.
    et al.
    Tian, Bo
    Eriksson, Kristofer
    Brucas, Rimantas
    Oscarsson, Sven
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Strömberg, Mattias
    Svedlindh, Peter
    Gunnarsson, Klas
    Magnetophoretic Transport Line System for Rapid On-Chip Attomole Protein Detection2015Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, nr 37, s. 10296-10302Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A lab-on-a-chip traveling wave magnetophoresis approach for sensitive and rapid protein detection is reported. In this method, a chip-based magnetic microarray comprising lines of micrometer-sized thin film magnetic elements was used to control the movement of magnetic beads (MBs). The MBs and the chip were functionalized, forming a sandwich-type assay. The MBs were transported across a detection area, and the presence of target molecules resulted in the immobilization of MBs within this area. Target quantification was accomplished by MB counting in the detection area using an optical microscope. In order to demonstrate the versatility of the microarray, biotinylated antiavidin was selected as the target protein. In this case, avidin-functionalized MBs and an avidin-functionalized detection area were used. With a total assay time of 1 to 1.5 h (depending on the labeling approach used), a limit of detection in the attomole range was achieved. Compared to on-chip surface plasmon resonance biodetection systems, our method has a larger dynamic range and is about a factor of 500 times more sensitive. Furthermore, our MB transportation system can operate in any chip-based biosensor platform, thereby significantly improving traditional biosensors.

  • 92.
    Belhomme, Marie-Charlotte
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Wang, Dong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Formation of C(sp(3))-C(sp(3)) Bonds by Palladium Catalyzed Cross-Coupling of alpha-Diazoketones and Allylboronic Acids2016Inngår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 18, nr 10, s. 2503-2506Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Palladium catalyzed cross-coupling of allylboronic acids with a-diazoketones was studied. The reaction selectively affords the linear allylic product. The reaction proceeds with formation of a new C(sp(3))-C(sp(3)) bond. The reaction was performed without an external oxidant, likely without the Pd-catalyst undergoing redox reactions.

  • 93. Bergenstråhle-Wohlert, Malin
    et al.
    Angles d'Ortoli, Thibault
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sjöberg, Nils A.
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Wohlert, Jakob
    On the anomalous temperature dependence of cellulose aqueous solubility2016Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, nr 4, s. 2375-2387Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The solubility of cellulose in water-based media is promoted by low temperature, which may appear counter-intuitive. An explanation to this phenomenon has been proposed that is based on a temperature-dependent orientation of the hydroxymethyl group. In this paper, this hypothesis is investigated using molecular dynamics computer simulations and NMR spectroscopy, and is discussed in conjunction with alternative explanations based on solvent–solute and solvent–solvent hydrogen bond formation respectively. It is shown that neither simulations nor experiments lend support to the proposed mechanism based on the hydroxymethyl orientation, whereas the two alternative explanations give rise to two distinct contributions to the hydration free energy of cellooligomers.

  • 94. Berggren, Gustav
    et al.
    Kaynak, Filiz Betul
    Anderlund, Magnus F.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Åkermark, Björn
    Institutionen för organisk kemi.
    Tetraethylammonium [12,12-diethyl-2,2,9,9-tetramethyl-1,4,7,10-tetraza-5,6-benzotridecane-3,8,11,13-tetra-one(4-)]oxidomanganate(V)2007Inngår i: Acta Crystallographica Section E, ISSN 1600-5368, Vol. E63, s. m2672-m2673Artikkel i tidsskrift (Fagfellevurdert)
  • 95. Berglund, Jennie
    et al.
    Angles d'Ortoli, Thibault
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Vilaplana, Francisco
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bergenstråhle-Wohlert, Malin
    Lawoko, Martin
    Henriksson, Gunnar
    Lindström, Mikael
    Wohlert, Jakob
    A molecular dynamics study of the effect of glycosidic linkage type in the hemicellulose backbone on the molecular chain flexibility2016Inngår i: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 88, nr 1, s. 56-70Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The macromolecular conformation of the constituent polysaccharides in lignocellulosic biomass influences their supramolecular interactions, and therefore their function in plants and their performance in technical products. The flexibility of glycosidic linkages from the backbone of hemicelluloses was studied by evaluating the conformational freedom of the φ and ψ dihedral angles using molecular dynamic simulations, additionally selected molecules were correlated with experimental data by NMR spectroscopy. Three types of β-(1→4) glycosidic linkages involving the monosaccharides (Glcp, Xylp and Manp) present in the backbone of hemicelluloses were defined. Different di- and tetrasaccharides with combinations of such sugar monomers from hemicelluloses were simulated and free energy maps of the φ - ψ space and hydrogen bonding patterns were obtained. The glycosidic linkage between Glc-Glc or Glc-Man (C-type) was the stiffest with mainly one probable conformation; the linkage from Man-Man or Man-Glc (M-type) was similar but with an increased probability for an alternative conformation making it more flexible, and the linkage between two Xyl-units (X-type) was the most flexible with two almost equally populated conformations. Glycosidic linkages of the same type showed essentially the same conformational space in both disaccharides and in the central region of tetrasaccharides. Different probabilities of glycosidic linkage conformations in the backbone of hemicelluloses can be directly estimated from the free energy maps, which to a large degree affect the overall macromolecular conformations of these polymers. The information gained contributes to an increased understanding of hemicelluloses’ function both in the cell wall and in technical products.

  • 96.
    Bermejo Gomez, Antonio
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Erbing, Elis
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Batuecas, Maria
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Vazquez-Romero, Ana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Martin-Matute, Belen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Iridium-Catalyzed Isomerization/Bromination of Allylic Alcohols: Synthesis of alpha-Bromocarbonyl Compounds2014Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, nr 34, s. 10703-10709Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    alpha-Brominated ketones and aldehydes, with two adjacent electrophilic carbon atoms, are highly valuable synthetic intermediates in organic synthesis, however, their synthesis from unsymmetrical ketones is very challenging, and current methods suffer from low selectivity. We present a new, reliable, and efficient method for the synthesis of alpha-bromocarbonyl compounds in excellent yields and with excellent selectivities. Starting from allylic alcohols as the carbonyl precursors, the combination of a 1,3-hydrogen shift catalyzed by iridium(III) with an electrophilic bromination gives alpha-bromoketones and aldehydes in good to excellent yields. The selectivity of the process is determined by the structure of the starting allylic alcohol; thus, alpha-bromoketones formally derived from unsymmetrical ketones can be synthesized in a straightforward and selective manner.

  • 97.
    Bermejo Gómez, Antonio
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ahlsten, Nanna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Platero-Prats, Ana E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Martín-Matute, Belén
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthesis of 4,5-disubstituted 2-aminothiazoles from a,b-unsaturated ketones: Preparation of 5-benzyl-4-methyl-2-aminothiazolium hydrochloride salt2014Inngår i: Organic Syntheses, ISSN 0078-6209, Vol. 91, s. 185-200Artikkel i tidsskrift (Fagfellevurdert)
  • 98.
    Bermejo Gómez, Antonio
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Cortes, Miguel Angel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lübcke, Marvin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Karolinska Institutet, Sweden.
    Johansson, Magnus J.
    Halldin, Christer
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Karolinska Insitutet, Sweden.
    Schou, Magnus
    Efficient DBU accelerated synthesis of F-18-labelled trifluoroacetamides2016Inngår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 52, nr 97, s. 13963-13966Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nucleophilic F-18-fluorination of bromodifluoromethyl derivatives was performed using [F-18] Bu4NF in the presence of DBU(1,8-diazabicyclo[5.4.0]undec-7-ene). This novel procedure provided a diverse set of [F-18] trifluoroacetamides in good to excellent radiochemical conversions. A mechanism where DBU acts as organomediator in this transformation is proposed.

  • 99.
    Bermejo Gómez, Antonio
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Cortes, Miguel Angel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lübcke, Marvin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Karolinska Intitutet, Sweden.
    Johansson, Magnus J.
    Schou, Magnus
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Karolinska Intitutet, Sweden.
    Synthesis of trifluoromethyl moieties by late-stage copper (I) mediated nucleophilic fluorination2017Inngår i: Journal of fluorine chemistry, ISSN 0022-1139, E-ISSN 1873-3328, Vol. 194, s. 51-57Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The nucleophilic fluorination of bromodifluoromethyl derivatives mediated by the complex (PPh3)(3)CuF is described. Under the reaction conditions, different trifluoroacetates, trifluorolcetones, trifluoroarenes and trifluoroacetamides were obtained in good yields.

  • 100.
    Bermejo Gómez, Antonio
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Holmberg, Pär
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Martin-Matute, Belén
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Transition metal-catalyzed redox isomerization of codeine and morphine in water2014Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, nr 74, s. 39519-39522Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A water-soluble rhodium complex formed from commercially available [Rh(COD)(CH3CN)(2)]BF4 and 1,3,5-triaza-7-phosphaadamantane (PTA) catalyzes the isomerization of both codeine and morphine into hydrocodone and hydromorphone with very high efficiency. The reaction is performed in water, allowing isolation of the final products by simple filtration, which results in very high isolated yields. The reactions can be easily scaled up to 100 g.

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