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  • 1. Aguilera, Adriana Freites
    et al.
    Tolvanen, Pasi
    Heredia, Shuyana
    Muñoz, Marta González
    Samson, Tina
    Oger, Adrien
    Verove, Antoine
    Eränen, Kari
    Leveneur, Sebastien
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Industrial Chemistry & Reaction Engineering, Department of Chemical Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Salmi, Tapio
    Epoxidation of fatty acids and vegetable oils assisted by microwaves catalyzed by a cation exchange resin2018In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 57, no 11, p. 3876-3886Article in journal (Refereed)
    Abstract [en]

    Epoxidation of oleic acid and cottonseed oil was conducted in a semibatch reactor with in-situ-formed percarboxylic acid (peracetic acid or perpropionic acid), using hydrogen peroxide as an oxidizing agent and carboxylic acid (acetic acid or propionic acid) as oxygen carriers. Amberlite IR-120 was implemented as the catalyst. The system was comprised of a loop reactor, where the mixture was pumped through a single-mode cavity in which microwave irradiation was introduced. A heat exchanger was integrated into the system to replace microwave heating, to compare the results obtained via microwave heating versus conventional heating. The catalyst loading effect was studied, as well as the influence of microwave irradiation and the implementation of the SpinChem rotating bed reactor (RBR), in hopes of decreasing the influence of the internal mass transfer. The application of microwave irradiation results in an improvement of the reaction yield in the absence of a catalyst.

  • 2.
    Akkarasamiyo, Sunisa
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sawadjoon, Supaporn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Orthaber, Andreas
    Samec, Joseph S. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Tsuji-Trost Reaction of Non-Derivatized Allylic Alcohols2018In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, no 14, p. 3488-3498Article in journal (Refereed)
    Abstract [en]

    Palladium-catalyzed allylic substitution of non-derivatized enantioenriched allylic alcohols with a variety of uncharged N-, S-, C- and O-centered nucleophiles using a bidentate BiPhePhos ligand is described. A remarkable effect of the counter ion (X) of the XPd[kappa(2)-BiPhePhos][kappa(3)-C3H5] was observed. When ClPd[kappa(2)-BiPhePhos][eta(3)-C3H5] (complexI) was used as catalyst, non-reproducible results were obtained. Study of the complex by X-ray crystallography, (PNMR)-P-31 spectroscopy, and ESI-MS showed that a decomposition occurred where one of the phosphite ligands was oxidized to the corresponding phosphate, generating ClPd[kappa(1)-BiPhePhosphite-phosphate][eta(3)-C3H5] species (complexII). When the chloride was exchanged to the weaker coordinating OTf- counter ion the more stable Pd[kappa(2)-BiPhePhos][eta(3)-C3H5](+)+[OTf] (-) (complexIII) was formed. ComplexIII performed better and gave higher enantiospecificities in the substitution reactions. ComplexIII was evaluated in Tsuji-Trost reactions of stereogenic non-derivatized allylic alcohols. The desired products were obtained in good to excellent yields (71-98%) and enantiospecificities (73-99%) for both inter- and intramolecular substitution reactions with only water generated as a by-product. The methodology was applied to key steps in total synthesis of (S)-cuspareine and (+)-lentiginosine. A reaction mechanism involving a palladium hydride as a key intermediate in the activation of the hydroxyl group is proposed in the overall transformation.

  • 3.
    Akkarasamiyo, Sunisa
    et al.
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Sawadjoon, Supaporn
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Samec, Joseph S. M.
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Tsuji-Trost Reaction of Non-Derivatized Allylic Alcohols2018In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, no 14, p. 3488-3498Article in journal (Refereed)
    Abstract [en]

    Palladium-catalyzed allylic substitution of non-derivatized enantioenriched allylic alcohols with a variety of uncharged N-, S-, C- and O-centered nucleophiles using a bidentate BiPhePhos ligand is described. A remarkable effect of the counter ion (X) of the XPd[kappa(2)-BiPhePhos][kappa(3)-C3H5] was observed. When ClPd[kappa(2)-BiPhePhos][eta(3)-C3H5] (complexI) was used as catalyst, non-reproducible results were obtained. Study of the complex by X-ray crystallography, (PNMR)-P-31 spectroscopy, and ESI-MS showed that a decomposition occurred where one of the phosphite ligands was oxidized to the corresponding phosphate, generating ClPd[kappa(1)-BiPhePhosphite-phosphate][eta(3)-C3H5] species (complexII). When the chloride was exchanged to the weaker coordinating OTf- counter ion the more stable Pd[kappa(2)-BiPhePhos][eta(3)-C3H5](+)+[OTf] (-) (complexIII) was formed. ComplexIII performed better and gave higher enantiospecificities in the substitution reactions. ComplexIII was evaluated in Tsuji-Trost reactions of stereogenic non-derivatized allylic alcohols. The desired products were obtained in good to excellent yields (71-98%) and enantiospecificities (73-99%) for both inter- and intramolecular substitution reactions with only water generated as a by-product. The methodology was applied to key steps in total synthesis of (S)-cuspareine and (+)-lentiginosine. A reaction mechanism involving a palladium hydride as a key intermediate in the activation of the hydroxyl group is proposed in the overall transformation.

  • 4.
    Al-Smadi, Derar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Enugala, Thilak Reddy
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Norberg, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Kihlberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Widersten, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Synthesis of substrates for aldolase-catalyzed reactions - A comparison of methods for the synthesis of substituted phenylacetaldehydes2018In: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, Vol. 29, p. 1187-1190Article in journal (Refereed)
  • 5.
    Barrozo, Alexandre
    et al.
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Liao, Qinghua
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structural Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Esguerra, Mauricio
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Marloie, Gael
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Florian, Jan
    Loyola Univ Chicago, Dept Chem & Biochem, Chicago, IL 60660 USA..
    Williams, Nicholas H.
    Univ Sheffield, Dept Chem, Sheffield S3 7HF, S Yorkshire, England..
    Kamerlin, Shina C. Lynn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Computer simulations of the catalytic mechanism of wild-type and mutant beta-phosphoglucomutase2018In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 16, no 12, p. 2060-2073Article in journal (Refereed)
    Abstract [en]

    beta-Phosphoglucomutase (beta-PGM) has served as an important model system for understanding biological phosphoryl transfer. This enzyme catalyzes the isomerization of beta-glucose-1-phosphate to -glucose-6-phosphate in a two-step process proceeding via a bisphosphate intermediate. The conventionally accepted mechanism is that both steps are concerted processes involving acid-base catalysis from a nearby aspartate (D10) side chain. This argument is supported by the observation that mutation of D10 leaves the enzyme with no detectable activity. However, computational studies have suggested that a substrate-assisted mechanism is viable for many phosphotransferases. Therefore, we carried out empirical valence bond (EVB) simulations to address the plausibility of this mechanistic alternative, including its role in the abolished catalytic activity of the D10S, D10C and D10N point mutants of beta-PGM. In addition, we considered both of these mechanisms when performing EVB calculations of the catalysis of the wild type (WT), H20A, H20Q, T16P, K76A, D170A and E169A/D170A protein variants. Our calculated activation free energies confirm that D10 is likely to serve as the general base/acid for the reaction catalyzed by the WT enzyme and all its variants, in which D10 is not chemically altered. Our calculations also suggest that D10 plays a dual role in structural organization and maintaining electrostatic balance in the active site. The correct positioning of this residue in a catalytically competent conformation is provided by a functionally important conformational change in this enzyme and by the extensive network of H-bonding interactions that appear to be exquisitely preorganized for the transition state stabilization.

  • 6. Begum, Sartaz
    et al.
    Nyandror, Stephen
    Buriyo, Amelia
    Makangara, John
    Munissi, Joan
    Duffy, Sandra
    Varey, Vicky
    Erdelyi, Mate
    University of Gothenburg.
    Bioactivities of extracts , debromolaurintrerol and fucosterol from Macroalgae species2018In: Tanzania Journal of Science, ISSN 2507-7961, Vol. 44, no 2, p. 104-116Article in journal (Refereed)
    Abstract [en]

    Parasitic diseases including malaria, and other numerous microbial infections and physiological diseases are threatening the global population. Tanzanian coast shores are endowed with a variety of macroalgae (seaweeds), hitherto unsystematically explored to establish their biomedical potentials. Thus, antiplasmodial activity using malarial imaging assay, antimicrobial activity using microplate dilution technique, antioxidant activity using DPPH radical scavenging method and cytotoxicity using brine shrimp test were carried out on crude extracts from the selected species of algae (Acanthophora spicifera, Cystoseira myrica, Cystoseira trinodis, Laurencia filiformis, Padina boryana, Sargassum oligocystum, Turbinaria crateriformis, Ulva fasciata and Ulva reticulata) occurring along the coast of Tanzania. The extracts showed antimicrobial activities with MIC ranging from 0.3- 5.0 µg/mL against Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, Escherichia coli, Candida albicans and Cryptococcus neoformans; DPPH radical scavenging activity at EC50 1.0- 100 µg/mL and cytotoxicity on brine shrimp larvae with LC50 value ranging from20 - 1000 µg/mL. The extracts from C. myrica and P. boryana inhibited growth of Plasmodium falciparum (3D7 strain) by 80 and 71%, respectively at 40 µg/mL while a sesquiterpene debromolaurinterol (1) which was chromatographically isolated from C. myrica exhibited antiplasmodial activity with IC50 20 µM whereas a sterol fucosterol (2) from P. boryana showed weak activity at 40 µM. Bioactivities portrayed by the investigated extracts indicate their ingredients as potential sources of bioactive agents that warrant further explorations.

  • 7. Daikoku, S.
    et al.
    Pendrill, Robert
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kanie, Y.
    Ito, Y.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kanie, O.
    Synthesis and structural investigation of a series of mannose-containing oligosaccharides using mass spectrometry2018In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 16, no 2, p. 228-238Article in journal (Refereed)
    Abstract [en]

    A series of compounds associated with naturally occurring and biologically relevant glycans consisting of alpha-mannosides were prepared and analyzed using collision-induced dissociation (CID), energy-resolved mass spectrometry (ERMS), and H-1 nuclear magnetic resonance spectroscopy. The CID experiments of sodiated species of disaccharides and ERMS experiments revealed that the order of stability of mannosyl linkages was as follows: 6-linked > 4-linked >= 2-linked > 3-linked mannosyl residues. Analysis of linear trisaccharides revealed that the order observed in disaccharides could be applied to higher glycans. A branched trisaccharide showed a distinct dissociation pattern with two constituting disaccharide ions. The estimation of the content of this ion mixture was possible using the disaccharide spectra. The hydrolysis of mannose linkages at 3- and 6-positions in the branched trisaccharide revealed that the 3-linkage was cleaved twice as fast as the 6-linkage. It was observed that the solution-phase hydrolysis and gas-phase dissociation have similar energetics.

  • 8.
    Daniel, Quentin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Duan, Lele
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Timmer, Brian J. J.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Chen, Hong
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Luo, Xiaodan
    Peking Univ, Coll Chem & Mol Engn, Beijing 100871, Peoples R China..
    Ambre, Ram
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Wang, Ying
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Zhang, Biaobiao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Zhang, Peili
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Wang, Lei
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Li, Fusheng
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Sun, Junliang
    Peking Univ, Coll Chem & Mol Engn, Beijing 100871, Peoples R China..
    Ahlquist, Mårten S. G.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Water Oxidation Initiated by In Situ Dimerization of the Molecular Ru(pdc) Catalyst2018In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 8, no 5, p. 4375-4382Article in journal (Refereed)
    Abstract [en]

    The mononuclear ruthenium complex [Ru(pdc)L-3] (H(2)pdc = 2,6-pyridinedicarboxylic acid, L = N-heterocycles such as 4-picoline) has previously shown promising catalytic efficiency toward water oxidation, both in homogeneous solutions and anchored on electrode surfaces. However, the detailed water oxidation mechanism catalyzed by this type of complex has remained unclear. In order to deepen understanding of this type of catalyst, in the present study, [Ru(pdc)(py)(3)] (py = pyridine) has been synthesized, and the detailed catalytic mechanism has been studied by electrochemistry, UV-vis, NMR, MS, and X-ray crystallography. Interestingly, it was found that once having reached the Ru-IV state, this complex promptly formed a stable ruthenium dimer [Ru-III(pdc)(py)(2)-O-Ru-IV(pdc)(py)(2)](+). Further investigations suggested that the present dimer, after one pyridine ligand exchange with water to form [Ru-III(pdc)(py)(2)-O-Ru-IV(pdc)(py)(H2O)](+), was the true active species to catalyze water oxidation in homogeneous solutions.

  • 9.
    Dhillon, Prakriti
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Cobalt-catalysed, regioselective C-H activation of amides with unsymmetrical 1,3-diynes using 8-aminoquinoline as a bidentate directing group2018Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    A cobalt-catalysed, ortho-directed, C-H activation of 8-aminoquinoline amides for the preparation of functionalised isoquinolones is reported. The C-H activation was performed with the amide derived from 8-aminoquinoline which acts as a bidentate directing group to facilitate the C-H activation at the ortho carbon atom of the amide towards annulation/cyclisation, with unsymmetrical 1,3-diynes. The work presented here is an exploration of the regiochemical outcome of an efficient and a novel route of synthesis that tries to gain a deeper insight into the regioselective preference for C-H activated annulations that result in the formation of a diverse range of alkynylated regioisomeric heterocycles. Of the four possible regioisomers, only one is formed as the major product depending on the stereoelectronic properties of the diyne in combination with the nature of the 8-aminoquinoline amide.

  • 10.
    Dias, Jorge T.
    et al.
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Svedberg, Gustav
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Nystrand, Mats
    Thermo Fisher Sci IDD, Global Res & Dev, Uppsala, Sweden..
    Svahn Andersson, Helene
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Gantelius, Jesper
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Rapid signal enhancement method for nanoprobe-based biosensing (vol 7, 2017)2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, no 1, article id 8184Article in journal (Refereed)
    Abstract [en]

    In the Methods section of this Article references 18 to 22 are incorrectly cited. The correct references were omitted from the reference list and appear below as references 1-5. References 18 to 22 are correctly cited in Introduction and Results and Discussion sections. "AuNPs of 10 nm in diameter were prepared following the protocol described by Bastus et al.18." should read: "AuNPs of 10 nm in diameter were prepared following the protocol described by Bastus et al.1." "AgNPs of 90 nm in diameter were prepared following the protocol described by Rivero et al.19." should read: "AgNPs of 90 nm in diameter were prepared following the protocol described by Rivero et al.2" "The size was determined by UV-Vis spectroscopy according to the AgNPs size theory demonstrated by Malynych20." should read: "The size was determined by UV-Vis spectroscopy according to the AgNPs size theory demonstrated by Malynych3." "The coupling of antibody to the NPs was prepared following a modified version of a protocol previously reported by Puertas et al.21." should read: "The coupling of antibody to the NPs was prepared following a modified version of a protocol previously reported by Puertas et al.4." "Microarrays were prepared as previously reported by our group22." should read: "Microarrays were prepared as previously reported by our group5.

  • 11. Dorau, Robin
    et al.
    Görbe, Tamás
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Svedendahl Humble, Maria
    Improved Enantioselectivity of Subtilisin Carlsberg Towards Secondary Alcohols by Protein Engineering2018In: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 19, no 4, p. 338-346Article in journal (Refereed)
    Abstract [en]

    Generally, the catalytic activity of subtilisin Carlsberg (SC) for transacylation reactions with secondary alcohols in organic solvent is low. Enzyme immobilization and protein engineering was performed to improve the enantioselectivity of SC towards secondary alcohols. Possible amino-acid residues for mutagenesis were found by combining available literature data with molecular modeling. SC variants were created by site-directed mutagenesis and were evaluated for a model transacylation reaction containing 1-phenylethanol in THF. Variants showing high E values (>100) were found. However, the conversions were still low. A second mutation was made, and both the E values and conversions were increased. Relative to that shown by the wild type, the most successful variant, G165L/M221F, showed increased conversion (up to 36 %), enantioselectivity (E values up to 400), substrate scope, and stability in THF.

  • 12.
    Elgland, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Synthesis and application of β-configured [18/19F]FDGs: Novel prosthetic CuAAC click chemistry fluoroglycosylation tools for amyloid PET imaging and cancer theranostics2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Positron emission tomography (PET) is a non-invasive imaging method that renders three-dimensional images of tissue that selectively has taken up a radiolabelled organic compound, referred to as a radiotracer. This excellent technique provides clinicians with a tool to monitor disease progression and to evaluate how the patient respond to treatment. The by far most widely employed radiotracer in PET is called 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG), which is often referred to as the golden standard in PET. From a molecular perspective, [18F]FDG is an analogue of glucose where a hydroxyl group has been replaced with a radioactive fluorine atom (18F). It is well known that covalent attachment of carbohydrates (i.e., glycosylation) to biomolecules tend to improve their properties in the body, in terms of; improved pharmacokinetics, increased metabolic stability and faster clearance from blood and other non-specific tissue. It is therefore natural to pursuit the development of a [18F]fluoroglycosylation method where [18F]FDG is chemically conjugated to a ligand with high affinity for a given biological target (e.g., tumors or disease-associated protein aggregates).

    This thesis describes a novel [18F]fluoroglycosylation method that in a simple and general manner facilitate the conjugation of [18F]FDG to biological ligands using click chemistry. The utility of the developed [18F]fluoroglycosylation method is demonstrated by radiolabelling of curcumin, thus forming a tracer that may be employed for diagnosis of Alzheimer’s disease. Moreover, a set of oligothiophenes were fluoroglycosylated for potential diagnosis of Alzheimer’s disease but also for other much rarer protein misfolding diseases (e.g., Creutzfeldt-Jakob disease and systemic amyloidosis). In addition, the synthesis of a series of 19F-fluoroglycosylated porphyrins is described which exhibited promising properties not only to detect but also to treat melanoma cancer. Lastly, the synthesis of a set of 19F-fluorinated E-stilbenes, structurally based on the antioxidant resveratrol is presented. The E-stilbenes were evaluated for their capacity to spectrally distinguish between native and protofibrillar transthyretin in the pursuit of finding diagnostic markers for the rare but severe disease, transthyretin amyloidosis.

  • 13. Erdelyi, Mate
    et al.
    Pupier, Marion
    Nuzillard, Jean-Marc
    Wist, Julien
    Schlörer, Nils
    Kuhn, Stefan
    Steinbeck, Christoph
    Williams, Antony
    Butts, Craig
    Claridge, Tim
    Mikhova, Bozhana
    Robien, Wolfgang
    Dashti, Hesam
    Eghbalnia, Hamid
    Fares, Christophe
    Adam, Christian
    Pavel, Kessler
    Moriaud, Fabrice
    Elyashberg, Mikhail
    Argyropoulos, Dimitris
    Perez, Manuel
    Giraudeau, Patrick
    Gil, Roberto
    Trevorrow, Paul
    Jeannerat, Damien
    A cross-platform format to associate NMR-extracted data (NMReDATA) to chemical structures2018Conference paper (Refereed)
  • 14. Forssén, P.
    et al.
    Multia, E.
    Samuelsson, Jörgen
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Andersson, M.
    Aastrup, T.
    Altun, S.
    Wallinder, D.
    Wallbing, L.
    Liangsupree, T.
    Riekkola, M. -L
    Fornstedt, Torgny
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Reliable Strategy for Analysis of Complex Biosensor Data2018In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 90, no 8, p. 5366-5374Article in journal (Refereed)
    Abstract [en]

    When using biosensors, analyte biomolecules of several different concentrations are percolated over a chip with immobilized ligand molecules that form complexes with analytes. However, in many cases of biological interest, e.g., in antibody interactions, complex formation steady-state is not reached. The data measured are so-called sensorgram, one for each analyte concentration, with total complex concentration vs time. Here we present a new four-step strategy for more reliable processing of this complex kinetic binding data and compare it with the standard global fitting procedure. In our strategy, we first calculate a dissociation graph to reveal if there are any heterogeneous interactions. Thereafter, a new numerical algorithm, AIDA, is used to get the number of different complex formation reactions for each analyte concentration level. This information is then used to estimate the corresponding complex formation rate constants by fitting to the measured sensorgram one by one. Finally, all estimated rate constants are plotted and clustered, where each cluster represents a complex formation. Synthetic and experimental data obtained from three different QCM biosensor experimental systems having fast (close to steady-state), moderate, and slow kinetics (far from steady-state) were evaluated using the four-step strategy and standard global fitting. The new strategy allowed us to more reliably estimate the number of different complex formations, especially for cases of complex and slow dissociation kinetics. Moreover, the new strategy proved to be more robust as it enables one to handle system drift, i.e., data from biosensor chips that deteriorate over time.

  • 15.
    Giovannoli, Cristina
    et al.
    Univ Turin, Italy.
    Passini, Cinzia
    Univ Turin, Italy.
    Di Nardo, Fabio
    Univ Turin, Italy.
    Anfossi, Laura
    Univ Turin, Italy.
    Baggiani, Claudio
    Univ Turin, Italy.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Affinity Capillary Electrochromatography of Molecularly Imprinted Thin Layers Grafted onto Silica Capillaries Using a Surface-Bound Azo-Initiator and Living Polymerization2018In: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 10, no 2, article id 192Article in journal (Refereed)
    Abstract [en]

    Molecularly imprinted thin layers were prepared in silica capillaries by using two different surface polymerization strategies, the first using 4,4-azobis(4-cyanovaleric acid) as a surface-coupled radical initiator, and the second, S-carboxypropyl-S'-benzyltrithiocarbonate as a reversible addition-fragmentation chain transfer (RAFT) agent in combination with 2,2-azobisisobutyronitrile as a free radical initiator. The ability to generate imprinted thin layers was tested on two different polymerization systems: (i) a 4-vinylpyridine/ethylene dimethacrylate (4VP-EDMA) in methanol-water solution with 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) as a template; and (ii) methacrylic acid/ethylene dimethacrylate (MAA-EDMA) in a chloroform solution with warfarin as the template molecule. The binding properties of the imprinted capillaries were studied and compared with those of the corresponding non-imprinted polymer coated capillaries by injecting the template molecule and by measuring its migration times relative to a neutral and non-retained marker. The role of running buffer hydrophobicity on recognition was investigated by studying the influence of varying buffer acetonitrile concentration. The 2,4,5-T-imprinted capillary showed molecular recognition based on a reversed phase mechanism, with a decrease of the template recognition in the presence of higher acetonitrile content; whereas warfarin-imprinted capillaries showed a bell-shaped trend upon varying the acetonitrile percentage, illustrating different mechanisms underlying imprinted polymer-ligand recognition. Importantly, the results demonstrated the validity of affinity capillary electrochromatography (CEC) to screen the binding properties of imprinted layers.

  • 16. Gisbert, Patricia
    et al.
    Trillo, Paz
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Organic Chemistry Dpt. and Instituto de Sintesis Organica (ISO).
    Pastor, Isidro M.
    Comparative Study of Catalytic Systems Formed by Palladium and Acyl-Substituted Imidazolium Salts2018In: CHEMISTRYSELECT, ISSN 2365-6549, Vol. 3, no 3, p. 887-893Article in journal (Refereed)
    Abstract [en]

    Amino amides, which are readily accessible from amino acids, were used in the preparation of both monoamido and diamido functionalized imidazolium salts in very straightforward protocols. Different catalytic systems formed with palladium(II) acetate and acyl functionalized imidazolium salts were tested in the Matsuda-Heck reaction. The comparative study revealed that the presence of one carbamoyl moiety in the N-heterocyclic carbene precursor is more beneficial during the catalytic process. Thus, better activity was observed with the catalytic system formed using 3-benzyl-1-(N-phenylcarbamoyl-methyl)imidazolium chloride in a 1:1 metal/ligand ratio. Moreover, this fact was evidenced by means of UV/vis studies.

  • 17.
    Gonzalez, Miguel A. Cortes
    et al.
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Nordeman, Patrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preparative Medicinal Chemistry.
    Gomez, Antonio Bermejo
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden;Karolinska Inst, AstraZeneca PET Ctr, SE-17176 Stockholm, Sweden.
    Meyer, Denise N.
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Antoni, Gunnar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preparative Medicinal Chemistry.
    Schou, Magnus
    Karolinska Inst, AstraZeneca PET Ctr, SE-17176 Stockholm, Sweden.
    Szabo, Kalman J.
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    [18F]fluoro-benziodoxole: a no-carrier-added electrophilic fluorinating reagent. Rapid, simple radiosynthesis, purification and application for fluorine-18 labelling2018In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 54, no 34, p. 4286-4289Article in journal (Refereed)
    Abstract [en]

    Operationally simple radiosynthesis and purification of [F-18]fluoro-benziodoxole was developed starting from a cyclotron produced [F-18]F- precursor, [F-18]TBAF, and tosyl-benziodoxole. The synthetic utility of [F-18]fluoro-benziodoxole was demonstrated by electrophilic fluorocyclization of o-styrilamides proceeding with high RCC (typically 50-90%) and high molar activity (up to 396 GBq mol(-1)).

  • 18.
    González Miera, Greco
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martínez-Castro, Elisa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Acceptorless Alcohol Dehydrogenation: OH vs NH Effect in Bifunctional NHC–Ir(III) Complexes2018In: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 37, no 5, p. 636-644Article in journal (Refereed)
    Abstract [en]

    Bifunctional complexes bearing N-heterocyclic carbene (NHC) ligands functionalized with hydroxy or amine groups were synthesized to measure the beneficial effect of different modes of metal–ligand cooperation in the acceptorless dehydrogenation of alcohols. In comparison to complexes with an amine moiety, hydroxy-functionalized iridium catalysts showed superior activity. In contrast to alcohols, 1,4-diols underwent cyclization to give the corresponding tetrahydrofurans without involving dehydrogenation processes. Mechanistic investigations to rationalize the “OH effect” in these types of complexes have been undertaken.

  • 19.
    Gudmundsson, Arnar
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Gustafson, Karl P. J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yang, Bin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Efficient Formation of 2,3-Dihydrofurans via Iron-Catalyzed Cycloisomerization of alpha-Allenols2018In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 8, no 1, p. 12-16Article in journal (Refereed)
    Abstract [en]

    Herein, we report a highly efficient iron-catalyzed intramolecular nucleophilic cyclization of alpha-allenols to furnish substituted 2,3-dihydrofurans under mild reaction conditions. A highly diastereoselective variant of the reaction was developed as well, giving diastereomeric ratios of up to 98:2. The combination of the iron-catalyzed cycloisomerization with enzymatic resolution afforded the 2,3-dihydrofuran in high ee. A detailed DFT study provides insight into the reaction mechanism and gives a rationalization for the high chemo-and diastereoselectivity.

  • 20.
    Gustafson, Karl P. J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Studies on Metalloenzymatic Dynamic Kinetic Resolutions and Iron-Catalyzed Reactions of Allenes2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The main focus of this thesis lies in the development of new transition metal-catalyzed chemoenzymatic dynamic kinetic resolutions (DKR) of both alcohols and amines. The first part of the thesis deals with the development of new heterogeneous systems for the DKR of amines. The racemization catalysts in these different systems are all composed of palladium nanoparticles supported on either mesoporous silica or incorporated in a biocomposite that is composed of a bioactive cross-linked enzyme aggregate. 

    The second part of the thesis deals with the development of a homogeneous iron catalyst in the racemization of sec-alcohols for the implementation in a chemoenzymatic DKR. Two protocols for the racemization of sec-alcohols are reported. The first one could not be combined with a chemoenzymatic kinetic resolution, although this was overcome in the second iron based protocol. 

    Following the successful iron catalyzed chemoenzymatic DKR of sec-alcohols, the iron catalyst was used in the cyclization of α-allenic alcohols and N-protected amines to furnish 2,3-dihydrofurans and 2,3-dihydropyrroles, respectively. The cyclization is proceeding in a diastereoselective manner.

    The last part of the thesis deals with attempts to further elucidate the mechanism of activation of a known ruthenium racemization catalyst. X-ray absorption spectroscopy using synchrotron radiation was used for this purpose.

  • 21.
    Görbe, Tamás
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Heterogeneous catalysis in racemization and kinetic resolution along a journey in protein engineering2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The first part of my thesis concerns the use of heterogeneous acidic resins for racemization of tert-alcohols without any side-product formation. The focus was to develop a system which can be further extended to a DKR protocol consisting of an enzymatic KR reaction. Based on our knowledge of the resins, an unexpected migratory DKR protocol turned out to be an efficient method for the synthesis of carbocyclic allylic carbinols.

    The development of enzyme and metal catalyst hybrids was already an ongoing theme in our group. A supporter-free biohybrid catalyst was developed which can be used in several different types of reactions. The Pd(0)-CalB CLEA catalyst was applied in a two-step-cascade transformation and in the DKR of benzylic primary amines. The catalyst was characterized by different analytical techniques, to understand its composition and structure.

    The enzymes have always been the main focus of the studies and therefore wild type enzymes were initially utilized. However, these natural biocatalysts are associated with certain limitations. In contrast, protein engineering allows for enzymes to be modified and optimized. We have used the technique to create a subtilisin Carlsberg mutant, which was studied both by modeling and in vitro. The mutant was found to catalyze the (S)-selective transesterification of sec-alcohols containing long aliphatic carbon chains, and it also exhibited higher performance in organic solvent.

    The last project concerned the protein engineering of CalA enzyme towards tert-alcohols. The kinetic resolution of tert-alcohols with this enzyme is very slow but it occurs with good enantioselectivity. The aim was therefore to improve the activity of CalA via protein engineering. Seven amino acids were mutated close to the active site and a library was created based on our prediction. Throughout the screening, a few variants showed higher activity, which were sequenced and further analyzed in the transesterification of tert-alcohols.

  • 22.
    Görbe, Tamás
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lihammar, Richard
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Heterogeneous Acid-Catalyzed Racemization of Tertiary Alcohols2018In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, no 1, p. 77-80Article in journal (Refereed)
    Abstract [en]

    Tertiary alcohols are important structural motifs in natural products and building blocks in organic synthesis but only few methods are known for their enantioselective preparation. Chiral resolution is one of these approaches that leaves one enantiomer (50% of the material) unaffected. An attractive method to increase the efficiency of those resolutions is to racemize the unaffected enantiomer. In the present work, we have developed a practical racemization protocol for tertiary alcohols. Five different acidic resin materials were tested. The Dowex 50WX8 was the resin of choice since it was capable of racemizing tertiary alcohols without any byproduct formation. Suitable solvents and a biphasic system were investigated, and the optimized system was capable of racemizing differently substituted tertiary alcohols.

  • 23.
    Heshmat, Mojgan
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Privalov, Timofei
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Structurally Flexible Oxocarbenium/Borohydride Ion Pair: Dynamics of Hydride Transfer on the Background of Conformational Roaming2018In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 122, no 23, p. 5098-5106Article in journal (Refereed)
    Abstract [en]

    We apply Born-Oppenheimer molecular dynamics to the practically significant [dioxane-H(+)-acetone]-[(C6F5)(3)B-H(-)] and [Et2O-H(+)-OCPr2][(C6F5)(3)B-H(-)] ion pair intermediates. Dynamics of hydride transfer in cation/anion ion pair takes place on the background of large amplitude configurational changes. Geometry of oxocarbenium/borohydride ion pairs is flexible, meaning that we uncover significant actual structural disorder at a finite temperature. Therefore, although the starting structure can be fairly close to the configurational area of the hydride transfer transition state (TS) and despite a low potential energy barrier (ca. 1.5 kcal/mol, according to the literature), already at T approximate to 325 K the system can remain ignorant of the TS region and move round and about (roam) in the configurational space for a period of time in the range between 10 and 100 ps. This indicates structural flexibility of oxocarbenium/borohydride ion pair on apparently a flat potential energy landscape of cation/anion interaction, and this has not been taken into consideration by the free energy estimations in static considerations made thus far. The difference between the dynamics-based representation of the system versus the static representation amounts to the difference between quasi-bimolecular versus unimolecular descriptions of the hydride transfer step.

  • 24.
    Heshmat, Mojgan
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Privalov, Timofei
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Surprisingly Flexible Oxonium/Borohydride Ion Pair Configurations2018In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 122, no 15, p. 3713-3727Article in journal (Refereed)
    Abstract [en]

    We investigate the geometry of oxonium/borohydride ion pairs [ether-H(+) ether] [LA-H(-)] with dioxane, THF, and Et2O as ethers and B(C6F5)(3) as the Lewis acid (LA). The question is about possible location of the disolvated proton [ether -H(+) -ether], with respect to the hydride of the structurally complex [LA -H(-)] anion. Using Born Oppenheimer molecular dynamics and a comparison of the potential and free energies of the optimized configurations, we show that herein considered ion pairs are much more flexible geometrically than previously thought. Conformers with different locations of cations with respect to anions are governed by a flat energy -landscape. We found a novel configuration in which oxonium is below [LA-11((-))], with respect to the direction of borane -> hydride vector, and the proton -hydride distance is ca. 6 A. With calculations of the vibrational spectra of [ether-H(+)-ether][(C6F5)(3)B-H(-)] for dioxane, THF, and Et2O as ethers, we investigate the manifestation of SSLB-type (short, strong, low -barrier) hydrogen bonding in the OHO motif of an oxonium cation.

  • 25.
    Hsu, Yu-Cheng
    et al.
    Acad Sinica, Inst Chem, Taipei 11529, Taiwan;Natl Taiwan Univ, Dept Chem, Taipei 10161, Taiwan.
    Wang, Vincent Cho-Chien
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Acad Sinica, Inst Chem, Taipei 11529, Taiwan.
    Au-Yeung, Ka-Chun
    Acad Sinica, Inst Chem, Taipei 11529, Taiwan.
    Tsai, Chung-Yu
    Acad Sinica, Inst Chem, Taipei 11529, Taiwan.
    Chang, Chun-Chi
    Acad Sinica, Inst Chem, Taipei 11529, Taiwan.
    Lin, Bo-Chao
    Acad Sinica, Inst Chem, Taipei 11529, Taiwan.
    Chan, Yi-Tsu
    Natl Taiwan Univ, Dept Chem, Taipei 10161, Taiwan.
    Hsu, Chao-Ping
    Acad Sinica, Inst Chem, Taipei 11529, Taiwan.
    Yap, Glenn P. A.
    Univ Delaware, Dept Chem & Biochem, Newark, DE 19716 USA.
    Jurca, Titel
    Univ Cent Florida, Dept Chem, Orlando, FL 32816 USA;Univ Cent Florida, Cluster Rational Design Catalysts Energy Applicat, Orlando, FL 32816 USA.
    Ong, Tiow-Gan
    Acad Sinica, Inst Chem, Taipei 11529, Taiwan;Natl Chiao Tung Univ, Dept Appl Chem, Hsinchu 300, Taiwan.
    One-Pot Tandem Photoredox and Cross-Coupling Catalysis with a Single Palladium Carbodicarbene Complex2018In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 57, no 17, p. 4622-4626Article in journal (Refereed)
    Abstract [en]

    The combination of conventional transition-metal-catalyzed coupling (2e(-) process) and photoredox catalysis (1e(-) process) has emerged as a powerful approach to catalyze difficult cross-coupling reactions under mild reaction conditions. Reported is a palladium carbodicarbene (CDC) complex that mediates both a Suzuki-Miyaura coupling and photoredox catalysis for C-N bond formation upon visible-light irradiation. These two catalytic pathways can be combined to promote both conventional transition-metal-catalyzed coupling and photoredox catalysis to mediate C-H arylation under ambient conditions with a single catalyst in an efficient one-pot process.

  • 26.
    Hur, Deniz
    et al.
    Anadolu Univ, Turkey; Bionkit Co Ltd, Turkey.
    Say, Mehmet Girayhan
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Bionkit Co Ltd, Turkey.
    Diltemiz, Sibel E.
    Anadolu Univ, Turkey; Bionkit Co Ltd, Turkey.
    Duman, Fatma
    Anadolu Univ, Turkey.
    Ersoz, Arzu
    Anadolu Univ, Turkey; Bionkit Co Ltd, Turkey.
    Say, Ridvan
    Anadolu Univ, Turkey; Bionkit Co Ltd, Turkey.
    3D Micropatterned All-Flexible Microfluidic Platform for Microwave-Assisted Flow Organic Synthesis2018In: CHEMPLUSCHEM, ISSN 2192-6506, Vol. 83, no 1, p. 42-46Article in journal (Refereed)
    Abstract [en]

    A large-area, all-flexible, microwaveable polydimethoxysilane microfluidic reactor was fabricated by using a 3D printing system. The sacrificial microchannels were printed on polydimethoxysilane substrates by a direct ink writing method using water-soluble Pluronic F-127 ink and then encapsulated between polydimethoxysilane layers. The structure of micron-sized channels was analyzed by optical and electron microscopy techniques. The fabricated flexible microfluidic reactors were utilized for the acetylation of different amines under microwave irradiation to obtain acetamides in shorter reaction times and good yields by flow organic synthesis.

  • 27.
    Jiang, Yan
    et al.
    Stockholm University, Stockholm.
    Deiana, Luca
    Stockholm University, Stockholm.
    Alimohammadzadeh, Rana
    Stockholm University, Stockholm.
    Liu, Leifeng
    Stockholm University, Stockholm.
    Sun, Junliang
    Stockholm University, Stockholm.
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Stockholm University, Stockholm.
    Highly Diastereo- and Enantioselective Cascade Synthesis of Bicyclic Lactams in One-Pot2018In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 2018, no 9, p. 1158-1164Article in journal (Refereed)
    Abstract [en]

    A versatile and highly stereoselective synthetic route to functionalized bi- and tricyclic lactams (up to > 20:1 dr and 99 % ee) in one pot from simple starting materials (allylic alcohols, enals, diamines and amino alcohols) using cascade transformations promoted by chiral amine/Brønsted or metal/chiral amine/Brønsted relay catalysis is disclosed. Here molecular oxygen is employed as the terminal oxidant for the latter relay catalysis approach. 

  • 28. Jo, Sunhwan
    et al.
    Myatt, Daniel
    Qi, Yifei
    Doutch, James
    Clifton, Luke A.
    Im, Wonpil
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Multiple Conformational States Contribute to the 3D Structure of a Glucan Decasaccharide: A Combined SAXS and MD Simulation Study2018In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 122, no 3, p. 1169-1175Article in journal (Refereed)
    Abstract [en]

    The inherent flexibility of carbohydrates is dependent on stereochemical arrangements, and characterization of their influence and importance will give insight into the three-dimensional structure and dynamics. In this study, a beta-(1 -> 4)/beta-(1 -> 3)-linked glucosyl decasaccharide is experimentally investigated by synchrotron small-angle X-ray scattering from which its radius of gyration (R-g) is obtained. Molecular dynamics (MD) simulations of the decasaccharide show four populated states at each glycosidic linkage, namely, syn- and anti-conformations. The calculated R-g values from the MD simulation reveal that in addition to syn-conformers the presence of anti-psi conformational states is required to reproduce experimental scattering data, unveiling inherent glycosidic linkage flexibility. The CHARMM36 force field for carbohydrates thus describes the conformational flexibility of the decasaccharide very well and captures the conceptual importance that anti-conformers are to be anticipated at glycosidic linkages of carbohydrates.

  • 29.
    Jorner, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Influence of Aromaticity on Excited State Structure, Reactivity and Properties2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes work that could help development of new photochemical reactions and light-absorbing materials. Focus is on the chemical concept "aromaticity" which is a proven conceptual tool in developing thermal chemical reactions. It is here shown that aromaticity is also valuable for photochemistry. The influence of aromaticity is discussed in terms of structure, reactivity and properties. With regard to structure, it is found that photoexcited molecules change their structure to attain aromatic stabilization (planarize, allow through-space conjugation) or avoid antiaromatic destabilization (pucker). As for reactivity, it is found that stabilization/destabilization of reactants decrease/increase photoreactivity, in accordance with the Bell-Evans-Polanyi relationship. Two photoreactions based on excited state antiaromatic destabilization of the substrates are reported. Finally, with respect to properties, it is shown that excited state energies can be tuned by considering aromatic effects of both the electronic ground state and the electronically excited states. The fundamental research presented in this thesis forms a foundation for the development of new photochemical reactions and design of compounds for new organic electronic materials.

  • 30.
    Jorner, Kjell
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Jahn, Burkhard O.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC. SciClus GmbH & Co. KG, Moritz-von-Rohr-Str. 1a, 07745 Jena, Germany .
    Bultinck, Patrick
    SciClus GmbH & Co. KG, Moritz-von-Rohr-Str. 1a, 07745 Jena, Germany.
    Ottosson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Triplet state homoaromaticity: concept, computational validation and experimental relevance2018In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 9, no 12, p. 3165-3176Article in journal (Refereed)
    Abstract [en]

    Cyclic conjugation that occurs through-space and leads to aromatic properties is called homoaromaticity. Here we formulate the homoaromaticity concept for the triplet excited state (T1) based on Baird's 4n rule and validate it through extensive quantum-chemical calculations on a range of different species (neutral, cationic and anionic). By comparison to well-known ground state homoaromatic molecules we reveal that five of the investigated compounds show strong T1 homoaromaticity, four show weak homoaromaticity and two are non-aromatic. Two of the compounds have previously been identified as excited state intermediates in photochemical reactions and our calculations indicate that they are also homoaromatic in the first singlet excited state. Homoaromaticity should therefore have broad implications in photochemistry. We further demonstrate this by computational design of a photomechanical “lever” that is powered by relief of homoantiaromatic destabilization in the first singlet excited state.

  • 31.
    Kalepu, Jagadeesh
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Gandeepan, Parthasarathy
    Georg August Univ Gottingen, Inst Organ & Biomol Chem, Tammannstr 2, D-37077 Gottingen, Germany.
    Ackermann, Lutz
    Georg August Univ Gottingen, Inst Organ & Biomol Chem, Tammannstr 2, D-37077 Gottingen, Germany.
    Pilarski, Lukasz T.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    C4-H indole functionalisation: precedent and prospects2018In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 9, no 18, p. 4203-4216Article in journal (Refereed)
    Abstract [en]

    C4-decorated indoles feature in a plethora of bioactive and functional compounds of importance to natural product synthesis, material sciences, as well as crop protection and pharmaceutical industries. Traditionally, their syntheses largely involved harsh stoichiometric metalations and radical reactions. However, transition metal catalysed C-H activation has recently evolved into a powerful strategy for the late-stage diversification of indoles at the C4-H position. Modern photoredox, enzymatic and precious transition metal catalysis represent the key stimuli for developing challenging C-C and C-Het bond forming transformations under mild reaction conditions. Herein, we discuss the evolution and application of these methods for the step-economical transformations of otherwise inert C4-H bonds up to December 2017.

  • 32.
    Kerdphon, Sutthichat
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    NHC,P- and N,P-Iridium Catalysts for Hydrogenations and Hydrogen Transfer Reactions2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The work described in this thesis is focused on hydrogenation and hydrogen transfer reactions using iridium catalysts. The first part concerns the use of N-heterocyclic carbene-phosphine iridium complexes in alkylation reactions (Chapters 2 and 3) and the hydrogenation of ketones (Chapter 4). A number of N-heterocyclic carbene-phosphine iridium complexes have been prepared and evaluated as catalysts for C-N bond formation of amides using alcohols as the electrophile. This catalytic system can be used with a wide range of substrates at low catalyst loading (only 0.5 mol%) to furnish the desired products in up to 98% isolated yield. The achiral N-heterocyclic carbene-phosphine iridium complexes were also found to catalyze the methylation of ketones with methanol under mild conditions to afford the mono-methylated products in up to 98% isolated yield with low catalyst loading (1.0 mol%). Additionally, several chiral N-heterocyclic carbene-phosphine iridium complexes were synthesized and evaluated in asymmetric hydrogenation of ketones. The reactions were carried out at room temperature under base-free conditions to obtain the chiral alcohols in up to 96% ee in 30 minutes.

    The second part of this thesis (Chapter 5) details the preparation of new N,P-iridium complexes which were found to be highly efficient catalysts for the asymmetric hydrogenation of challenging tetrasubstituted olefins. This catalytic system results in optically active compounds of high enantiomeric excess (up to 98% ee) as the single diasteroisomer.

  • 33.
    Kervefors, Gabriella
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Becker, Antonia
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dey, Chandan
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Olofsson, Berit
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Metal-free formal synthesis of phenoxazine2018In: Beilstein Journal of Organic Chemistry, ISSN 2195-951X, E-ISSN 1860-5397, Vol. 14, p. 1491-1497Article in journal (Refereed)
    Abstract [en]

    A transition metal-free formal synthesis of phenoxazine is presented. The key step of the sequence is a high-yielding O-arylation of a phenol with an unsymmetrical diaryliodonium salt to provide an ortho-disubstituted diaryl ether. This species was cyclized to acetylphenoxazine in moderate yield. The overall yield in the three-step sequence is 72% based on recovered diaryl ether. An interesting, unusually stable iodine(III) intermediate in the O-arylation was observed by NMR and could be converted to the product upon longer reaction time.

  • 34. Kiss, Anita
    et al.
    Herman, Bianka Edina
    Görbe, Tamás
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mernyak, Erzsebet
    Molnar, Barnabas
    Wolfling, Janos
    Szecsi, Mihaly
    Schneider, Gyula
    Synthesis of novel 17-triazolyl-androst-5-en-3-ol epimers via Cu(I)-catalyzed azide-alkyne cycloaddition and their inhibitory effect on 17 alpha-hydroxylase/ C-17,C-20-lyase2018In: Steroids, ISSN 0039-128X, E-ISSN 1878-5867, Vol. 135, p. 79-91Article in journal (Refereed)
    Abstract [en]

    The regioselective Cu(I)-catalyzed 1,3-dipolar cycloaddition of 17 alpha- and 17 beta-azidoandrost-5-en-3 beta-ol epimers (3b and 5b) with different terminal alkynes afforded novel 1,4-substituted triazolyl derivatives (8a-k and 9a-k). For the preparation of 5'-iodo-l',2',3'-triazoles (8m-n and 9m-n), an improved method was developed, directly from steroidal azides and terminal alkynes, in reaction mediated by Cul and IC1 as iodinating agents. Acetolysis and subsequent hydrolysis of 8n and 9n yielded 5'-hydroxy-l',2',3'-triazoles 8o and 9o. The inhibitory effect of 8a-o, 9a-o, 3, and 5 on rat testicular C-17,C-20-lyase was investigated by means of an in vitro radioincubation technique. The results revealed that the C-17 epimers of steroidal triazoles influence the C-17,C-20-lyase effect. Inhibitors were found only in the 17 alpha-triazolyl series (8a-o), whereas in the C-17 azide pair the 17 beta compound (5b) was more potent.

  • 35.
    Konwar, Lakhya Jyoti
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Samikannu, Ajaikumar
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mäki-Arvela, Päivi
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Turku, Finland .
    Efficient C-C coupling of bio-based furanics and carbonyl compounds to liquid hydrocarbon precursors over lignosulfonate derived acidic carbocatalysts2018In: Catalysis Science & Technology, ISSN 2044-4753, E-ISSN 2044-4761, Vol. 8, no 9, p. 2449-2459Article in journal (Refereed)
    Abstract [en]

    This paper demonstrates the catalytic potential of novel Na-lignosulfonate (LS) derived meso/macroporous solid protonic acids upon C–C coupling of bio-based furanics and carbonyl compounds. The materials demonstrated catalytic activity for solventless hydroxyalkylation/alkylation (HAA) of 2-methylfuran with furfural, acetone, butanal, cyclohexanone, levulinic acid and α-angelica lactone under mild reaction conditions (50–60 °C) producing branched-chain C12–C16 hydrocarbon precursors in yields approaching 96%. Moreover, the carbon materials exhibiting high total acidity (6–6.4 mmol g−1) outperformed sulfonic acid resins (Amberlyst®70, Amberlite®IR120 and LS resin), zeolites and liquid acids (p-toluenesulfonic acid, acetic acid and phenol). In fact, the most active carbocatalyst (60LS40PS350H+) exhibited the same turnover frequency as p-toluenesulfonic acid (186 h−1) upon furfural conversion but with an improved HAA product yield (up to 88%) and reusability, maintaining 98% of its original activity up to seven reaction cycles. The observed catalytic activity and operational stability of the LS derived acidic carbocatalysts were attributed to the strongly Brønsted acidic –SO3H groups covalently incorporated into their structural carbon framework and the promotional effects of hydrophilic surface functional groups (–COOH and –OH) favoring adsorption of oxygenated reactant molecules.

  • 36.
    Krajangsri, Suppachai
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Development of Asymmetric Iridium Catalysed Hydrogenation Reactions2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The focus of the work presented in this thesis is the development of iridium-catalysed asymmetric hydrogenation reactions.

    The first part of this thesis covers the development of dynamic kinetic resolution in asymmetric hydrogenation of chiral, racemic secondary allylic alcohols, which are converted to chiral saturated alcohols with high dr and ee. In this study, a wide range of substrates was successfully hydrogenated to give good results, with up to 95:5 dr and 99% ee. Moreover, a number of different allylic alcohol derivatives were also investigated and found to undergo the DKR of hydrogenation with good results.

    The second part of this thesis is directed towards the development of regioselective asymmetric mono-hydrogenation of 1,4- and 1,5-disubstituted 1,4-cyclohexadienes. Under optimized hydrogenation conditions, high yield of regioselective mono-hydrogenated products and excellent enantioselectivity were observed in most cases. The usefulness of the reaction was demonstrated in the preparation of important chiral α,β-unsaturated ketones in good yield and excellent ee of up to 96%. Our novel method provides a general route to this important class of compounds.

    The third part concerns the development of asymmetric hydrogenation of β-hydroxy silanes. It was observed that under hydrogenation conditions, β-hydroxy silanes undergo Peterson olefination to form terminal olefins which are then hydrogenated using an Ir catalyst. A new class of Ir-N,P catalysts were prepared and provided high yield with excellent ee in up to 99%. In addition, the reaction was highly chemoselective and could be tuned to hydrogenate either an olefin or a β-hydroxy silane depending on the choice of catalyst and reaction conditions.

    The final part describes the asymmetric hydrogenation of enamides. A variety of oxazolidinone-enamides were prepared and evaluated in this reaction. High yields, (up to 99%) and excellent ee, (up to 99%) were obtained.

  • 37.
    Krajangsri, Suppachai
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yang, Jianping
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Massaro, Luca
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Andersson, Pher
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Iridium-Catalysed Enantioselective Hydrogenation of Enamides2018Manuscript (preprint) (Other academic)
    Abstract [en]

    A variety of oxazolidinone-enamides were prepared and evaluated in this reaction. High yields, (up to 99%) and excellent ee, (up to 99%) were obtained.

  • 38.
    Kumaniaev, Ivan
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Samec, Joseph S. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Valorization of Quercus suber Bark toward Hydrocarbon Bio-Oil and 4-Ethylguaiacol2018In: ACS sustainable chemistry and engineering, ISSN 2168-0485, Vol. 6, no 5, p. 5737-5742Article in journal (Refereed)
    Abstract [en]

    A reductive fractionation process for the valorization of Quercus suber bark toward hydrocarbons in gasoline and diesel ranges and optionally 4-ethylguaiacol has been developed. The procedure involves three steps: (1) tandem hydrogen-free Pd/C-catalyzed transfer hydrogenolysis of lignin where the carbohydrates serve as an inherent hydrogen donor under slightly alkaline conditions to also facilitate the depolymerization of suberin, (2) optional distillation, to isolate the 4-ethylguaiacol, (3) hydrodeoxygenation of the mixture from the first step by a Pt-MoO3/TiO2 catalyst generated hydrocarbons in gasoline and diesel ranges. The yield of 4-ethylguaiacol (90% purity) is 2.6% of dry bark weight (12% of acid insoluble lignin), and yield of hydrocarbon bio-oil is 42% of dry bark weight. This corresponds to a theoretical maximum yield of 77% for lignin and suberin. The carbon yield of the obtained bio-oil is thereby 64% from the total initial bark.

  • 39. Li, F.
    et al.
    Xu, C.
    Wang, X.
    Wang, Y.
    Du, J.
    Sun, Licheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Visible light-driven oxygen evolution using a binuclear Ru-bda catalyst2018In: Cuihuà xuébào, ISSN 0253-9837, E-ISSN 1872-2067, Vol. 39, no 3, p. 446-452Article in journal (Refereed)
    Abstract [en]

    Binuclear ruthenium complexes bearing the 2,2'-bipyridine-6,6'-dicarboxylate (bda) ligand have been demonstrated to be highly active catalysts towards water oxidation with CeIV as an oxidant. However, the catalytic properties of ruthenium dimers have not yet been explored for visible light-driven water oxidation. Herein, the photocatalytic performance of a dipyridyl propane-bridged ruthenium dimer 2 was investigated in comparison with its monomeric precursor, [Ru(bda)(pic)2] (1), in CH3CN/phosphate buffer mixed solvent in a three-component system including a photosensitizer and a sacrificial electron acceptor. Experimental results showed that the activity of each catalyst was strongly dependent on the content of CH3CN in the phosphate buffer, which not only affected the driving force for water oxidation, but also altered the kinetics of the reaction, probably through different mechanisms associated with the O–O bond formation. As a result, dimer 2 showed significantly higher activity than monomer 1 in the solvent containing a low content of CH3CN, and comparable activities were attained with a high content of CH3CN in the solvent. Under the optimal conditions, complex 2 achieved a turnover number of 638 for photocatalytic O2 evolution.

  • 40.
    Liu, Jun
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials. Jiangsu Univ, Sch Environm & Safety Engn, Biofuels Inst, Zhenjiang.
    Bacher, Markus
    Univ Nat Resources & Appl Life Sci BOKU, Dept Chem, Vienna.
    Rosenau, Thomas
    Univ Nat Resources & Appl Life Sci BOKU, Dept Chem, Vienna; Åbo Akad Univ, Lab Wood & Paper Chem, Johan Gadolin Proc Chem Ctr, Turku.
    Willfoer, Stefan
    Åbo Akad Univ, Lab Wood & Paper Chem, Johan Gadolin Proc Chem Ctr, Turku.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Potentially Immunogenic Contaminants in Wood-Based and Bacterial Nanocellulose: Assessment of Endotoxin and (1,3)-β-d-Glucan Levels2018In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, no 1, p. 150-157Article in journal (Refereed)
    Abstract [en]

    Knowledge gaps in the biosafety data of the nanocellulose (NC) for biomedical use through various routes of administration call for closer look at health and exposure evaluation. This work evaluated the potentially immunogenic contaminants levels, for example, endotoxin and (1,3)-β-d-glucan, in four representative NCs, that is, wood-based NCs and bacterial cellulose (BC). The hot-water extracts were analyzed with ELISA assays, HPSEC-MALLS, GC, and NMR analysis. Varying levels of endotoxin and (1,3)-β-d-glucan contaminats were found in these widely used NCs. Although the β-(1,3)-d-glucan was not detected from the NMR spectra due to the small extract samples amount (2–7 mg), the anomerics and highly diastereotopic 6-CH2 signals may suggest the presence of β-(1,4)-linkages with β-(1,6) branching in the polysaccharides of NCs’ hot-water extracts, which were otherwise not detectable in the enzymatic assay. In all, the article highlights the importance of monitoring various water-soluble potentially immunogenic contaminants in NC for biomedical use.

  • 41.
    Manzetti, Sergio
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics. Fjordforsk A/S, NanoFactory.
    Quantum chemical calculations of the active site of the solute-binding protein PsaA from Streptococcus pneumoniae explain electronic selectivity of metal binding2018In: Structural Chemistry, ISSN 1040-0400, E-ISSN 1572-9001, Vol. 29, no 2, p. 393-401Article in journal (Refereed)
    Abstract [en]

    Streptococcus pneumoniae is the world’s foremost bacterial pathogen. Virulence in the host is dependent on manganese acquisition via the PsaBCA permease. Crystallographic studies of its solute-binding protein component, PsaA, have previously shown that the nature of the metal ion bound by the protein modulates the conformational changes associated with its function. Notably, manganese and cadmium ions can be bound in a reversible manner, facilitating transport via PsaA, whereas zinc binds in an essentially irreversible manner preventing release to the permease. All three ionic species show a similar coordination in the PsaA crystal structures. A set of quantum chemical calculations have here been performed in order to differentiate between the ions in terms of electronic configuration. Based on natural bond orbital (NBO) analysis, the results show that manganese and cadmium bind more strongly to the protein than zinc, in that their coordination to the enzyme involves more shared electrons. Manganese has the highest indirect indicator of bonding strength and provides an unpaired electron that induces the formation of three bonds to the enzyme active site. Cadmium binds more strongly than zinc, though more weakly than manganese, and forms only ionic bonds in its ligand framework. These calculations indicate a concrete differentiation of the bonding states of the three active sites; however, bonding energies which can give more accurate estimates have not been computed presently. The calculations further show that the ionic radii are critical for the bonding state between the enzyme and the metal and that the conformational motions responsible for the PsaA’s functional cycle may depend on the ion binding strongly to the enzyme. Our results add important information of the PsaA-metal ion binding architecture to the existing crystallography data and aid in understanding the function of this protein.

  • 42.
    Marcos, Rocio
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Bertini, Federica
    CNR, Inst Chim Composti Organometallici ICCOM, Via Madonna Piano 10, I-50019 Florence, Italy..
    Rinkevicius, Zilvinas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Peruzzini, Maurizio
    CNR, Inst Chim Composti Organometallici ICCOM, Via Madonna Piano 10, I-50019 Florence, Italy..
    Gonsalvi, Luca
    CNR, Inst Chim Composti Organometallici ICCOM, Via Madonna Piano 10, I-50019 Florence, Italy..
    Ahlquist, Mårten S. G.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Mechanistic Studies on NaHCO3 Hydrogenation and HCOOH Dehydrogenation Reactions Catalysed by a Fe-II Linear Tetraphosphine Complex2018In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, no 20, p. 5366-5372Article in journal (Refereed)
    Abstract [en]

    We present a theoretical extension of the previously published bicarbonate hydrogenation to formate and formic acid dehydrogenation catalysed by Fe-II complexes bearing the linear tetraphosphine ligand tetraphos-1. The hydrogenation reaction was found to proceed at the singlet surface with two competing pathways: A)H-2 association to the Fe-H species followed by deprotonation to give a Fe(H)(2) intermediate, which then reacts with CO2 to give formate. B)CO2 insertion into the Fe-H bond, followed by H-2 association and subsequent deprotonation. B was found to be slightly preferred with an activation energy of 22.8kcalmol(-1), compared to 25.3 for A. Further we have reassigned the Fe-H complex, as a Fe(H)(H-2), which undergoes extremely rapid hydrogen exchange.

  • 43.
    Marsavelski, Aleksandra
    et al.
    Rudjer Boskovic Inst, Div Organ Chem & Biochem, Computat Organ Chem & Biochem Grp, Bijenicka Cesta 54, Zagreb 10000, Croatia.;Univ Zagreb, Fac Sci, Dept Chem, Horvatovac 102a, Zagreb 10000, Croatia.;Uppsala Univ, Dept Cell & Mol Biol, BMC Box 596, S-75124 Uppsala, Sweden..
    Petrovic, Dusan
    Uppsala Univ, Dept Cell & Mol Biol, BMC Box 596, S-75124 Uppsala, Sweden..
    Bauer, Paul
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biophysics. KTH, Centres, Science for Life Laboratory, SciLifeLab. Uppsala Univ, Dept Cell & Mol Biol, BMC Box 596, S-75124 Uppsala, Sweden.
    Vianello, Robert
    Rudjer Boskovic Inst, Div Organ Chem & Biochem, Computat Organ Chem & Biochem Grp, Bijenicka Cesta 54, Zagreb 10000, Croatia..
    Kamerlin, Shina Caroline Lynn
    Uppsala Univ, Dept Cell & Mol Biol, BMC Box 596, S-75124 Uppsala, Sweden..
    Empirical Valence Bond Simulations Suggest a Direct Hydride Transfer Mechanism for Human Diamine Oxidase2018In: ACS OMEGA, ISSN 2470-1343, Vol. 3, no 4, p. 3665-3674Article in journal (Refereed)
    Abstract [en]

    Diamine oxidase (DAO) is an enzyme involved in the regulation of cell proliferation and the immune response. This enzyme performs oxidative deamination in the catabolism of biogenic amines, including, among others, histamine, putrescine, spermidine, and spermine. The mechanistic details underlying the reductive half-reaction of the DAO-catalyzed oxidative deamination which leads to the reduced enzyme cofactor and the aldehyde product are, however, still under debate. The catalytic mechanism was proposed to involve a prototropic shift from the substrateSchiff base to the product-Schiff base, which includes the ratelimiting cleavage of the C alpha-H bond by the conserved catalytic aspartate. Our detailed mechanistic study, performed using a combined quantum chemical cluster approach with empirical valence bond simulations, suggests that the rate-limiting cleavage of the C alpha-H bond involves direct hydride transfer to the topaquinone cofactor. a mechanism that does not involve the formation of a Schiff base. Additional investigation of the D373E and D373N variants supported the hypothesis that the conserved catalytic aspartate is indeed essential for the reaction; however, it does not appear to serve as the catalytic base, as previously suggested. Rather, the electrostatic contributions of the most significant residues (including D373), together with the proximity of the Cu2+ cation to the reaction site, lower the activation barrier to drive the chemical reaction.

  • 44. Masoud, Taheri
    et al.
    Mehran, Ghiaci
    Shchukarev, Andrey
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    A comparison between two Pd‐Ni catalysts supported on two different supports toward Suzuki‐Miyaura coupling reaction2018In: Applied organometallic chemistry, ISSN 0268-2605, E-ISSN 1099-0739, Vol. 32, no 5Article in journal (Refereed)
    Abstract [en]

    When a single metal fails to promote an efficient Suzuki?Miyaura coupling reaction at ambient temperature, the synergistic cooperation of two distinct metals might improve the reaction. To examine the synergistic effect of palladium and nickel for catalyzing Suzuki coupling reaction, g?C3N4 supported metal nanoparticles of PdO, NiO and Pd?PdO?NiO were prepared, characterized and their catalytic activities evaluated over different aryl halides at room temperature and 78 °C. The morphological characterization of Pd?PdO?NiO/g?C3N4 demonstrated that the bimetallic particles were uniformly dispersed over the g?C3N4 layers with diameters ranging from 3.5?7.7 nm. XPS analysis showed that nanoparticles of Pd?PdO?NiO consisted of Pd(II), Pd(0) and Ni(II) sites. The experiments performed on the catalytic activity of Pd?PdO?NiO/g?C3N4 showed that the prepared catalyst demonstrated an efficient activity without using toxic solvents.

  • 45.
    Mobarak, Hani
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis and analysis of carbohydrates related to bacterial polysaccharides2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The outer surface of bacteria is composed of around 75% carbohydrates, which are vital for the bacteria to survive and communicate with the host biological system. The thesis discusses different properties of carbohydrates that are essential for understanding the bacterial behavior in biological systems. The first three chapters give an overview of carbohydrates.

    The fourth chapter discusses the synthesis of four amide-substituted 3,6-dideoxy-α-D-galactopyranosides, namely, methyl α-3,6-dideoxy-3-formamido-, acetamido-, (R)-3-hydroxybutyramido-, and (4-hydroxybutyramido)-D-galactopyranoside. These sugars were found as components of some bacterial O-antigens; the study is a step toward the synthesis of oligosaccharides that contain them. The fifth chapter describes the exchange kinetics of the formyl and acetyl derivatives that were synthesized. Both of them have two conformational states for the amide side-chain. 13C-NMR saturation transfer experiments are utilized for these measurements to reveal more about their properties in solution.

    In chaptr six, NMR and conformational analysis of oligosaccharides related to the O-antigen of Yersinia enterocolitica O:3 bacteria were carried out to obtain more information regarding their 3D structure.

    Chapter seven is focusing on the development of CASPER, a program for rapid assignment of 1H- and 13C-NMR chemical shifts of bacterial lipopolysaccharides, by adding more sugars into its database and testing it for naturally occurring LPS as well as extending the scope for synthetic carbohydrates, which is planned to be developed further in the future.

  • 46.
    Moriou, Céline
    et al.
    CNRS, Inst Chim Subst Nat, Gif Sur Yvette, France.
    Da Silva, Adilson D.
    Univ Fed Juiz de Fora, Dept Quim, ICE, BR-Juiz De Fora, MG, Brazil.
    Vianelli Prado, Marcos Joel
    Univ Fed Juiz de Fora, Dept Quim, ICE, BR-Juiz De Fora, MG, Brazil.
    Denhez, Clément
    Univ Reims, Inst Chim Mol Reims, CNRS, UMR 7312,UFR Pharm, 51 Rue Cognacq Jay, Reims, France; Univ Reims, Multiscale Mol Modelling Platform, UFR Sci Exactes & Nat, Reims, France.
    Plashkevych, Oleksandr
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular Biology.
    Chattopadhyaya, Jyoti
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular Biology.
    Guillaume, Dominique
    Univ Reims, Inst Chim Mol Reims, CNRS, UMR 7312,UFR Pharm, 51 Rue Cognacq Jay, Reims, France.
    Clivio, Pascale
    Univ Reims, Inst Chim Mol Reims, CNRS, UMR 7312, UFR Pharm, 51 Rue Cognacq Jay, Reims, France.
    C2 '-F Stereoconfiguration As a Puckering Switch for Base Stacking at the Dinucleotide Level2018In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 83, no 4, p. 2473-2478Article in journal (Refereed)
    Abstract [en]

    Fluorine configuration at C2′ of the bis(2′-fluorothymidine) dinucleotide is demonstrated to drive intramolecular base stacking. 2′-β F-Configuration drastically reduces stacking compared to the 2′-α series. Hence, base stacking emerges as being tunable by the C2′-F stereoconfiguration through dramatic puckering variations scrutinized by NMR and natural bond orbital analysis. Accordingly, 2′-β F-isomer photoreactivity is significantly reduced compared to that of the 2′-α F-isomer.

  • 47.
    Olsén, Peter
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Oschmann, Michael
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Johnston, Eric V.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of highly functional carbamates through ring-opening of cyclic carbonates with unprotected alpha-amino acids in water2018In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 20, no 2, p. 469-475Article in journal (Refereed)
    Abstract [en]

    The present work shows that it is possible to ring-open cyclic carbonates with unprotected amino acids in water. Fine tuning of the reaction parameters made it possible to suppress the degree of hydrolysis in relation to aminolysis. This enabled the synthesis of functionally dense carbamates containing alkenes, carboxylic acids, alcohols and thiols after short reaction times at room temperature. When Glycine was used as the nucleophile in the ring-opening with four different five membered cyclic carbonates, containing a plethora of functional groups, the corresponding carbamates could be obtained in excellent yields (> 90%) without the need for any further purification. Furthermore, the orthogonality of the transformation was explored through ring-opening of divinylenecarbonate with unprotected amino acids equipped with nucleophilic side chains, such as serine and cysteine. In these cases the reaction selectively produced the desired carbamate, in 70 and 50% yield respectively. The synthetic design provides an inexpensive and scalable protocol towards highly functionalized building blocks that are envisioned to find applications in both the small and macromolecular arena.

  • 48. Orebom, Alexander
    et al.
    Verendel, J. Johan
    Samec, Joseph S. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry. RenFuel AB, Sweden.
    High Yields of Bio Oils from Hydrothermal Processing of Thin Black Liquor without the Use of Catalysts or Capping Agents2018In: ACS omega, ISSN 2470-1343, Vol. 3, no 6, p. 6757-6763Article in journal (Refereed)
    Abstract [en]

    Black liquor (BL) from the kraft pulping process has been treated at elevated temperatures (380 degrees C) in a batch reactor to give high yields of a bio oil comprising monomeric phenolic compounds that were soluble in organic solvents and mineral oil and a water fraction with inorganic salts. The metal content in the product was < 20 ppm after a simple extraction step. A correlation between concentration, temperature, and reaction time with respect to yield of desired product was found. At optimal reaction conditions (treating BL with 16 wt % dry substance at 380 degrees C for 20 min), the yield of extractable organics was around 80% of the original lignin with less than 7% of char. The product was analyzed by gel permeable chromatography, mass spectroscopy, nuclear magnetic resonance, elemental analysis, and inductively coupled plasma. It was found that a large fraction composed of mainly cresols, xylenols, and mesitols. This process provides a pathway to convert a major waste stream from a pulp mill into a refinery feed for fuel or chemical production, whereas at the same time the inorganic chemicals are recovered and can be returned back to the pulp mill.

  • 49.
    Pathi Pati, Stalin Reddy
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Development of new Catalytic Methods for the Selective Synthesis of Heterocycles2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the field of organic chemistry, the development of new catalytic methods for the synthesis of complex molecules from simple precursors is a top priority. The main focus of this thesis concerns the diastereoselective synthesis of heterocyclic compounds using main group elements as Lewis acid catalysts.

    The first part of this thesis deals with an annulation reaction of nitrones with oxiranes, aziridines, and thiiranes using Al(III) or In(III) catalysts. From this protocol, 1,4,2-dioxazinanes, 1,2,4-oxadiazinanes, and 1,4,2-oxathiazinanes were obtained in moderate to high yields with excellent diastereoselectivity. The transformation was found to be stereospecific and proceed via an SN2-mechanism.

    The second and third parts concern the development of In(III)-catalyzed annulation of carbonyl compounds, amines, and alkynyl enones. InBr3 was found to be an efficient catalyst for the activation of alkynyl enones in a multicomponent reaction with aldehydes and amines. The method affords cyclopenta[c]furans in high yields and in good to excellent diastereomeric ratios. Bicyclo[3.n.1]alkenone derivatives were formed via a double Michael addition reaction of cyclic ketones, amines, and alkynyl enones, in the presence of InCl3. The utility of these protocols was also demonstrated by sequential transformations.

    In the fourth part, AgOTf and CuI were found to be efficient catalysts for the activation of pyridine-substituted enynes towards enamines, providing indolizine derivatives in high yield and good diastereomeric ratios.

    In the last part of the thesis, 1,2-aminoarylation of γ,δ-unsaturated oxime esters with arylboronic acids using Ni catalysis is discussed. The protocol demonstrates the potential of Ni-catalysts for the generation of iminyl radicals to furnish functionalized pyrroline derivatives. The utility of this protocol was exemplified by transforming the pyrroline products to the corresponding pyrrole and pyrrolidine derivatives. 

  • 50.
    Pathipati, Stalin R.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    van der Werf, Angela
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selander, Nicklas
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Diastereoselective Synthesis of Polycyclic Indolizines with 2-(2-Enynyl)pyridines and Enamines2018In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 20, no 12, p. 3691-3694Article in journal (Refereed)
    Abstract [en]

    A diastereoselective metal-catalyzed reaction of 2-(2-enynyl)pyridines and cyclic enamines is reported. The method provides access to a variety of substituted indolizine derivatives by variation of the enyne component and the reaction conditions. Performing the reaction using a preformed enamine led to the formation of polycyclic indolizines. With in situ generated enamines, ketone-containing indolizine derivatives were obtained. An asymmetric reaction of 2-(2-enynyl)pyridines and enamines generated from an aldehyde and a catalytic amount of amine is presented.

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