lnu.sePublications
Change search
Link to record
Permanent link

Direct link
BETA
Ramström, Olof
Publications (7 of 7) Show all publications
Xie, S., Zhou, J., Chen, X., Kong, N., Fan, Y., Zhang, Y., . . . 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
Show others...
2019 (English)In: Materials Chemistry Frontiers, E-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 Society of Chemistry, 2019
National Category
Materials Chemistry
Research subject
Natural Science, Chemistry; Chemistry, Organic Chemistry
Identifiers
urn:nbn:se:lnu:diva-80778 (URN)10.1039/c8qm00516h (DOI)000457644400009 ()2-s2.0-85060918688 (Scopus ID)
Available from: 2019-02-22 Created: 2019-02-22 Last updated: 2019-08-29Bibliographically approved
Zhang, Y., Zhang, Y. & Ramström, O. (2019). Dynamic covalent kinetic resolution. Catalysis reviews. Science and engineering
Open this publication in new window or tab >>Dynamic covalent kinetic resolution
2019 (English)In: Catalysis reviews. Science and engineering, ISSN 0161-4940, E-ISSN 1520-5703Article in journal (Refereed) Epub ahead of print
Abstract [en]

Implemented with the highly efficient concept of Dynamic Kinetic Resolution (DKR), dynamic covalent chemistry can be a useful strategy for the synthesis of enantioenriched compounds. This gives rise to dynamic covalent kinetic resolution (DCKR), a subset of DKR that over the last decades has emerged as increasingly fruitful, with many applications in asymmetric synthesis and catalysis. All DKR protocols are composed of two important parts: substrate racemization and asymmetric transformation, which can lead to yields of >50% with good enantiomeric excesses (ee) of the products. In DCKR systems, by utilizing reversible covalent reactions as the racemization strategy, the substrate enantiomers can be easily interconverted without the presence of any racemase or transition metal catalyst. Enzymes or other chiral catalysts can then be adopted for the resolution step, leading to products with high enantiopurities. This tutorial review focuses on the development of DCKR systems, based on different reversible reactions, and their applications in asymmetric synthesis.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2019
Keywords
Dynamic kinetic resolution, dynamic covalent chemistry, asymmetric synthesis, organocatalysis, enzymatic catalysis
National Category
Chemical Sciences
Research subject
Natural Science, Chemistry
Identifiers
urn:nbn:se:lnu:diva-89312 (URN)10.1080/01614940.2019.1664031 (DOI)000486173200001 ()
Available from: 2019-09-26 Created: 2019-09-26 Last updated: 2019-09-26
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 2468-8274, Vol. 470, p. 138-144Article in journal (Refereed) Published
Abstract [en]

Asymmetric synthesis of N-aryloxazolidinones via dynamic kinetic resolution was developed. A ruthenium-based catalyst was used in the racemization of β-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. © 2019 Elsevier B.V.

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
Biochemistry and Molecular Biology
Research subject
Chemistry, Biochemistry
Identifiers
urn:nbn:se:lnu:diva-82851 (URN)10.1016/j.mcat.2019.03.020 (DOI)000469906600017 ()2-s2.0-85063965626 (Scopus ID)
Available from: 2019-05-23 Created: 2019-05-23 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 Fluoroquinolones. 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 Fluoroquinolones
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-Blackwell, 2019
Keywords
aggregation-induced emission, fluorescence quenching, fluoroquinolones, hydrogen bonds, water sensors
National Category
Chemical Sciences
Research subject
Natural Science, Chemistry
Identifiers
urn:nbn:se:lnu:diva-81699 (URN)10.1002/asia.201801916 (DOI)000461836500032 ()30762939 (PubMedID)2-s2.0-85062327816 (Scopus ID)
Available from: 2019-04-05 Created: 2019-04-05 Last updated: 2019-08-29Bibliographically 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 2468-8274, 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
Enzyme, Subtilisin Carlsberg, Candida antarctica lipase B, HIV, 1, 3-Oxathiolane
National Category
Biochemistry and Molecular Biology
Research subject
Chemistry, Biochemistry
Identifiers
urn:nbn:se:lnu:diva-82034 (URN)10.1016/j.mcat.2019.02.013 (DOI)000463293300007 ()2-s2.0-85061747406 (Scopus ID)
Available from: 2019-04-23 Created: 2019-04-23 Last updated: 2019-08-29Bibliographically 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
Show others...
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
Biochemistry and Molecular Biology
Research subject
Natural Science, Chemistry
Identifiers
urn:nbn:se:lnu:diva-86911 (URN)10.1016/j.bios.2019.111328 (DOI)000472696000013 ()31136921 (PubMedID)2-s2.0-85066129421 (Scopus ID)
Available from: 2019-07-18 Created: 2019-07-18 Last updated: 2019-08-29Bibliographically approved
Ren, Y., Xie, S., Grape, E. S., Inge, A. K. & Ramström, O. (2018). Multistimuli-Responsive Enaminitrile Molecular Switches Displaying H+-Induced Aggregate Emission, Metal Ion-Induced Turn-On Fluorescence, 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 Displaying H+-Induced Aggregate Emission, Metal Ion-Induced Turn-On Fluorescence, and Organogelation Properties
Show others...
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 super gelation 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 (Phi(F) up to 0.41) in the solid state. In response to Cu-II 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.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Biochemistry and Molecular Biology
Research subject
Chemistry, Biochemistry
Identifiers
urn:nbn:se:lnu:diva-78839 (URN)10.1021/jacs.8b09843 (DOI)000448755200025 ()30351138 (PubMedID)2-s2.0-85055124605 (Scopus ID)
Available from: 2018-11-15 Created: 2018-11-15 Last updated: 2019-08-29Bibliographically approved
Organisations

Search in DiVA

Show all publications