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Ramström, Olof
Publications (10 of 30) Show all publications
Xie, S., Zhou, J., Chen, X., Kong, N., Fan, Y., Hammer, G., . . . Yan, M. (2019). A versatile catalyst-free perfluoroaryl azide-aldehyde-amine conjugation reaction. MATERIALS CHEMISTRY FRONTIERS, 3(2), 251-256
Open this publication in new window or tab >>A versatile catalyst-free perfluoroaryl azide-aldehyde-amine conjugation reaction
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2019 (English)In: MATERIALS CHEMISTRY FRONTIERS, ISSN 2052-1537, Vol. 3, no 2, p. 251-256Article in journal (Refereed) Published
Abstract [en]

In a tri-component reaction, an electrophilically-activated perfluoroaryl azide, an enolizable aldehyde and an amine react readily at room temperature without any catalysts in solvents including aqueous conditions to yield a stable amidine conjugate. The versatility of this reaction is demonstrated in the conjugation of an amino acid without prior protection of the carboxyl group, and in the synthesis of antibiotic-nanoparticle conjugates.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2019
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-244534 (URN)10.1039/c8qm00516h (DOI)000457644400009 ()2-s2.0-85060918688 (Scopus ID)
Note

QC 20190403

Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2019-06-25Bibliographically approved
Zhang, Y., Xie, S., Yan, M. & Ramström, O. (2019). Enzyme- and ruthenium-catalyzed dynamic kinetic resolution involving cascade alkoxycarbonylations for asymmetric synthesis of 5-Substituted N-Aryloxazolidinones. Molecular Catalysis, 470, 138-144
Open this publication in new window or tab >>Enzyme- and ruthenium-catalyzed dynamic kinetic resolution involving cascade alkoxycarbonylations for asymmetric synthesis of 5-Substituted N-Aryloxazolidinones
2019 (English)In: Molecular Catalysis, ISSN 2468-8231, Vol. 470, p. 138-144Article in journal (Refereed) Published
Abstract [en]

AAsymmetric synthesis of N-aryloxazolidinones via dynamic kinetic resolution was developed. A ruthenium-based catalyst was used in the racemization of beta-anilino alcohols, while Candida antarctica lipase B (CAL-B) was applied for two selective alkoxycarbonylations operating in cascade. Various N-aryloxazolidinone derivatives were obtained in high yields and good enantiopurities.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Asymmetric synthesis, Candida Antarctica lipase B, Cascade alkoxycarbonylation, Dynamic kinetic resolution, Oxazolidinone, Candida, Isomers, Ruthenium, Yeast, Alkoxycarbonylation, Oxazolidinones, Kinetics
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-252525 (URN)10.1016/j.mcat.2019.03.020 (DOI)000469906600017 ()2-s2.0-85063965626 (Scopus ID)
Note

QC 20190613

Available from: 2019-06-13 Created: 2019-06-13 Last updated: 2019-06-25Bibliographically approved
Xie, S., Manuguri, S., Ramström, O. & Yan, M. (2019). Impact of Hydrogen Bonding on the Fluorescence of N-Amidinated Fluoroquinolone. Chemistry - An Asian Journal, 14(6), 910-916
Open this publication in new window or tab >>Impact of Hydrogen Bonding on the Fluorescence of N-Amidinated Fluoroquinolone
2019 (English)In: Chemistry - An Asian Journal, ISSN 1861-4728, E-ISSN 1861-471X, Vol. 14, no 6, p. 910-916Article in journal (Refereed) Published
Abstract [en]

The fluorescence properties of AIE-active N-amidinated fluoroquinolones, efficiently obtained by a perfluoroaryl azide-aldehyde-amine reaction, have been studied. The fluorophores were discovered to elicit a highly sensitive fluorescence quenching response towards guest molecules with hydrogen-bond-donating ability. This effect was evaluated in a range of protic/aprotic solvents with different H-bonding capabilities, and also in aqueous media. The influence of acid/base was furthermore addressed. The hydrogen-bonding interactions were studied by IR, NMR, UV/Vis and time-resolved fluorescence decay, revealing their roles in quenching of the fluorescence emission. Due to the pronounced quenching property of water, the N-amidinated fluoroquinolones could be utilized as fluorescent probes for quantifying trace amount of water in organic solvents.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2019
Keywords
aggregation-induced emission, fluorescence quenching, fluoroquinolones, hydrogen bonds, water sensors
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-248338 (URN)10.1002/asia.201801916 (DOI)000461836500032 ()30762939 (PubMedID)2-s2.0-85062327816 (Scopus ID)
Note

QC 20190408

Available from: 2019-04-08 Created: 2019-04-08 Last updated: 2019-04-08Bibliographically approved
Ren, Y., Hu, L. & Ramström, O. (2019). Multienzymatic cascade synthesis of an enantiopure (2R,5R)-1,3-oxathiolane anti-HIV agent precursor. Molecular Catalysis, 468, 52-56
Open this publication in new window or tab >>Multienzymatic cascade synthesis of an enantiopure (2R,5R)-1,3-oxathiolane anti-HIV agent precursor
2019 (English)In: Molecular Catalysis, ISSN 2468-8231, Vol. 468, p. 52-56Article in journal (Refereed) Published
Abstract [en]

An enantiopure (2R,5R)-1,3-oxathiolane was obtained using a multienzymatic cascade protocol. By employing a combination of surfactant-treated subtilisin Carlsberg and Candida antarctica lipase B, the absolute configuration of the resulting 1,3-oxathiolane ring was efficiently controlled, resulting in an excellent enantiomeric excess (>99%). This enantiopure 1,3-oxathiolane derivative is a key precursor to anti-HIV agents, such as lamivudine, through subsequent N-glycosylation.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
1, 3-Oxathiolane, Candida antarctica lipase B, Enzyme, HIV, Subtilisin Carlsberg
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-246434 (URN)10.1016/j.mcat.2019.02.013 (DOI)000463293300007 ()2-s2.0-85061747406 (Scopus ID)
Note

QC 20190329

Available from: 2019-03-29 Created: 2019-03-29 Last updated: 2019-04-29Bibliographically approved
Abellan-Flos, M., Timmer, B. J. J., Altun, S., Aastrup, T., Vincent, S. P. & Ramström, O. (2019). QCM sensing of multivalent interactions between lectins and well-defined glycosylated nanoplatforms. Biosensors & bioelectronics, 139, Article ID 111328.
Open this publication in new window or tab >>QCM sensing of multivalent interactions between lectins and well-defined glycosylated nanoplatforms
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2019 (English)In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 139, article id 111328Article in journal (Refereed) Published
Abstract [en]

Quartz crystal microbalance (QCM) methodology has been adopted to unravel important factors contributing to the "cluster glycoside effect" observed in carbohydrate-lectin interactions. Well-defined, glycosylated nanostructures of precise sizes, geometries and functionalization patterns were designed and synthesized, and applied to analysis of the interaction kinetics and thermodynamics with immobilized lectins. The nanostructures were based on Borromean rings, dodecaamine cages, and fullerenes, each of which carrying a defined number of carbohydrate ligands at precise locations. The synthesis of the Borromeates and dodecaamine cages was easily adjustable due to the modular assembly of the structures, resulting in variations in presentation mode. The binding properties of the glycosylated nanoplatforms were evaluated using flow-through QCM technology, as well as hemagglutination inhibition assays, and compared with dodecaglycosylated fullerenes and a monovalent reference. With the QCM setup, the association and dissociation rate constants and the associated equilibrium constants of the interactions could be estimated, and the results used to delineate the multivalency effects of the lectin-nanostructure interactions.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
QCM, Carbohydrates, Lectins, Multivalency, Nanoplatforms
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-255296 (URN)10.1016/j.bios.2019.111328 (DOI)000472696000013 ()31136921 (PubMedID)2-s2.0-85066129421 (Scopus ID)
Note

QC 20190730

Available from: 2019-07-30 Created: 2019-07-30 Last updated: 2019-07-30Bibliographically approved
Ren, Y., Svensson, P. H. & Ramström, O. (2018). A Multicontrolled Enamine Configurational Switch Undergoing Dynamic Constitutional Exchange. Angewandte Chemie International Edition, 57(21), 6256-6260
Open this publication in new window or tab >>A Multicontrolled Enamine Configurational Switch Undergoing Dynamic Constitutional Exchange
2018 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 57, no 21, p. 6256-6260Article in journal (Refereed) Published
Abstract [en]

A multiresponsive enamine-based molecular switch is presented, in which forward/backward configurational rotation around the C=C bond could be precisely controlled by the addition of an acid/base or metal ions. Fluorescence turn-on/off effects and large Stokes shifts were observed while regulating the switching process with Cu-II. The enamine functionality furthermore enabled double dynamic regimes, in which configurational switching could operate in conjunction with constitutional enamine exchange of the rotor part. This behavior was used to construct a prototypical dynamic covalent switch system through enamine exchange with primary amines. The dynamic exchange process could be readily turned on/off by regulating the switch status with pH.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2018
Keywords
dynamic exchange, enamines, fluorescence, E/Z isomerization, molecular switches
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-230434 (URN)10.1002/anie.201802994 (DOI)000432710100049 ()29601656 (PubMedID)2-s2.0-85046299449 (Scopus ID)
Note

QC 20180615

Available from: 2018-06-15 Created: 2018-06-15 Last updated: 2018-10-30Bibliographically approved
REN, Y., Xie, S., Grape, E., Inge, A. K. & Ramström, O. (2018). Multistimuli-Responsive Enaminitrile Molecular Switches DisplayingH+‑Induced Aggregate Emission, Metal Ion-Induced Turn-OnFluorescence, and Organogelation Properties. Journal of the American Chemical Society, 140(42), 13640-13643
Open this publication in new window or tab >>Multistimuli-Responsive Enaminitrile Molecular Switches DisplayingH+‑Induced Aggregate Emission, Metal Ion-Induced Turn-OnFluorescence, and Organogelation Properties
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2018 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 140, no 42, p. 13640-13643Article in journal (Refereed) Published
Abstract [en]

Multistimuli-responsive enaminitrile-based configurational switches displaying aggregation-induced emission (AIE), fluorescence turn-on effects, and supergelation properties are presented. The E-isomers dominated (>97%) in neutral/basic solution, and the structures underwent precisely controlled switching around the enamine C═C bond upon addition of acid/base. Specific fluorescence output was observed in response to different external input in the solution and solid states. In response to H+, configurational switching resulted in complete formation of the nonemissive Z-H+-isomers in solution, however displaying deep-blue to blue fluorescence (ΦF up to 0.41) in the solid state. In response to CuII in the solution state, the E-isomers exhibited intense, turn-on, blue-green fluorescence, which could be turned off by addition of competitive coordination. The acid/base-activated switching, together with the induced AIE-effects, further enabled the accomplishment of a responsive superorganogelator. In nonpolar solvents, a blue-fluorescent supramolecular gel was formed upon addition of acid to the E-isomer suspension. The gelation could be reversed by addition of base, and the overall, reversible process could be repeated at least five cycles.

National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-237425 (URN)10.1021/jacs.8b09843 (DOI)000448755200025 (PubMedID)2-s2.0-85055124605 (Scopus ID)
Note

QC 20181030

Available from: 2018-10-26 Created: 2018-10-26 Last updated: 2018-11-16Bibliographically approved
Schaufelberger, F., Timmer, B. J. J. & Ramström, O. (2018). Resolving a Reactive Organometallic Intermediate from Dynamic Directing Group Systems by Selective C-H Activation. Chemistry - A European Journal, 24(1), 101-104
Open this publication in new window or tab >>Resolving a Reactive Organometallic Intermediate from Dynamic Directing Group Systems by Selective C-H Activation
2018 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, no 1, p. 101-104Article in journal (Refereed) Published
Abstract [en]

Catalyst discovery from systems of potential precursors is a challenging endeavor. Herein, a new strategy applying dynamic chemistry to the identification of catalyst precursors from C-H activation of imines is proposed and evaluated. Using hydroacylation of imines as a model reaction, the selection of an organometallic reactive intermediate from a dynamic imine system, involving many potential directing group/metal entities, is demonstrated. The identity of the amplified reaction intermediate with the best directing group could be resolved in situ by ESI-MS, and coupling of the procedure to an iterative deconvolution protocol generated a system with high screening efficiency.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2018
Keywords
catalysis, C-H activation, directing group, dynamic chemistry, systems chemistry
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-221349 (URN)10.1002/chem.201705273 (DOI)000419046600016 ()29149517 (PubMedID)2-s2.0-85039907333 (Scopus ID)
Funder
Swedish Research CouncilEU, FP7, Seventh Framework Programme, 289033
Note

QC 20180117

Available from: 2018-01-17 Created: 2018-01-17 Last updated: 2018-01-17Bibliographically approved
Timmer, B., Schaufelberger, F., Hammarberg, D., Franzen, J., Ramström, O. & Dinér, P. (2018). Simple and Effective Integration of Green Chemistry and Sustainability Education into an Existing Organic Chemistry Course. Journal of Chemical Education, 95(8), 1301-1306
Open this publication in new window or tab >>Simple and Effective Integration of Green Chemistry and Sustainability Education into an Existing Organic Chemistry Course
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2018 (English)In: Journal of Chemical Education, ISSN 0021-9584, E-ISSN 1938-1328, Vol. 95, no 8, p. 1301-1306Article in journal (Refereed) Published
Abstract [en]

Green chemistry and sustainable development have become increasingly important topics for the education of future chemists. The cross-disciplinary nature of green chemistry and sustainable development often means these subjects are taught in conjunction with other subjects, such as organic chemistry and chemical engineering. Herein, a straightforward and efficient approach for vertical integration of green chemistry concepts within existing undergraduate organic chemistry courses is shown. The gradual self-evaluation, "greenification", and reassessment of an organic chemistry course at KTH Royal Institute of Technology from 2013 to 2017 is described, with particular focus on the laboratory course and a novel green chemistry project designed to promote sustainability thinking and reasoning. The laboratory project, which can also be conducted as an independent organic chemistry laboratory exercise, required students to critically evaluate variations of the same Pechmann condensation experiment according to the twelve principles of green chemistry. The course evaluation shows that, after the modifications, students feel more comfortable with the topics "green chemistry" and "sustainability" and consider these topics more important for their future careers. Furthermore, the ability of students to discuss and critically evaluate green chemistry parameters improved considerably as determined from the laboratory project reports.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
Second-Year Undergraduate, Organic Chemistry, Problem Solving/Decision Making, Testing/Assessment, Green Chemistry, Reactions
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-240202 (URN)10.1021/acs.jchemed.7b00720 (DOI)000442961800008 ()2-s2.0-85051517648 (Scopus ID)
Note

QC 20181217

Available from: 2018-12-17 Created: 2018-12-17 Last updated: 2018-12-17Bibliographically approved
Kravchenko, O., Timmer, B., Biedermann, M., Inge, K. & Ramström, O. (2018). Stable CAAC-based complexes in dynamic olefin metathesis. Paper presented at 256th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nanoscience, Nanotechnology and Beyond, AUG 19-23, 2018, Boston, MA. Abstract of Papers of the American Chemical Society, 256
Open this publication in new window or tab >>Stable CAAC-based complexes in dynamic olefin metathesis
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2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-238561 (URN)000447600002209 ()
Conference
256th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nanoscience, Nanotechnology and Beyond, AUG 19-23, 2018, Boston, MA
Note

QC 20181105

Available from: 2018-11-05 Created: 2018-11-05 Last updated: 2018-11-05Bibliographically approved
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