| 1. |
- Alam, Rauful, et al.
(author)
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Stereoselective intermolecular allylic C-H trifluoroacetoxylation of functionalized alkenes
- 2012
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In: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 134:21, s. 8778-8781
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Journal article (peer-reviewed)abstract
- Pd-catalyzed allylic C-H trifluoroacetoxylation of substituted alkenes was performed using PhI(OCOCF3)(2) as the oxidant and acyloxy source. Trifluoroacetoxylation of monosubstituted cyclopentenes and cyclohexenes proceeds with excellent regio- and diastereoselectivity. Studies with one of the possible (eta(3)-allyl)Pd(II) intermediates suggest that the reaction proceeds via stereoselective formation of Pd(IV) intermediates and subsequent stereo- and regioselective reductive elimination of the product.
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| 2. |
- Cumpstey, Ian, et al.
(author)
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Amine-linked diglycosides : Synthesis facilitated by the enhanced reactivity of allylic electrophiles, and glycosidase inhibition assays
- 2011
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In: Beilstein Journal of Organic Chemistry. - : Beilstein Institut. - 2195-951X .- 1860-5397. ; 7, s. 1-9
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Journal article (peer-reviewed)abstract
- Diglycose derivatives, consisting of two monosaccharides linked at non-anomeric positions by a bridging nitrogen atom, have been synthesised. Conversion of one of the precursor monosaccharide coupling components into an unsaturated derivative enhances its electrophilicity at the allylic position, facilitating coupling reactions. Mitsunobu coupling between nosylamides and 2,3-unsaturated-4-alcohols gave the 4-amino-pseudodisaccharides with inversion of configuration as single regio- and diastereoisomers. A palladium-catalysed coupling between an amine and a 2,3-unsaturated 4-trichloroacetimidate gave a 2-amino-pseudodisaccharide as the major product, along with other minor products. Derivatisation of the C=C double bond in pseudodisaccharides allowed the formation of Man(N4-6)Glc and Man(N4-6)Man diglycosides. The amine-linked diglycosides were found to show weak glycosidase inhibitory activity.
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| 3. |
- Cumpstey, Ian, et al.
(author)
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N-linked neodisaccharides: Synthesis facilitated by the enhanced reactivity of allylic electrophiles, and glycosidase inhibitory activity
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Other publication (other academic/artistic)abstract
- Neodisaccharides consisting of two monosaccharides linked by a bridging nitrogen atom have been synthesised. Converting one of the monosaccharide coupling components into an unsaturated derivative enhances its electrophilicity at the allylic position, facilitating coupling reactions. Mitsunobu coupling between nosylamides and 2,3-unsaturated 4-alcohols gave the 4-amino pseudodisaccharides with inversion of configuration as single regio- and diastereoisomers. A palladium catalysed coupling between an amine and a 2,3-unsaturated 4-trichloroacetimidate gave a 2-amino pseudodisaccharide as the major product along with other minor products. Derivatisation of the C=C double bond in pseudodisaccharides allowed the formation of Man(N4–6)Glc and Man(N4–6)Man neodisaccharides. The inhibitory activity of some N-linked neodisaccharides against the enzyme α-Glucosidase II is reported.
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| 4. |
- Lukinavicius, Grazvydas, et al.
(author)
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SiR-Hoechst is a far-red DNA stain for live-cell nanoscopy
- 2015
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 6
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Journal article (peer-reviewed)abstract
- Cell-permeable DNA stains are popular markers in live-cell imaging. Currently used DNA stains for live-cell imaging are either toxic, require illumination with blue light or are not compatible with super-resolution microscopy, thereby limiting their utility. Here we describe a far-red DNA stain, SiR-Hoechst, which displays minimal toxicity, is applicable in different cell types and tissues, and is compatible with super-resolution microscopy. The combination of these properties makes this probe a powerful tool for live-cell imaging.
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| 5. |
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| 6. |
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| 7. |
- Pershagen, Elias, et al.
(author)
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Designing reactivity-based responsive lanthanide probes for multicolor detection in biological systems
- 2014
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In: Coordination chemistry reviews. - : Elsevier BV. - 0010-8545 .- 1873-3840. ; 273, s. 30-46
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Research review (peer-reviewed)abstract
- Strategies for the design and synthesis of responsive luminescent probes based on lanthanide complexes are surveyed. The sensitive detection of analytes ranging from ions to small molecules to large biomolecules such as enzymes in complex biological milieu drives the quest for even more selective probes with improved photophysical properties and broad availability for non-specialists. Here, reactivity-based probes, i.e. those in which the sensing event is accompanied by the breaking of a covalent bond are reviewed, with an emphasis on the strategies that could be generalized to the detection of additional analytes. Syntheses providing advanced cyclen-based ligands with minimum effort, as well as those that enable post-complexation modification of lanthanide-bound structures are presented. (C) 2013 Elsevier B.V. All rights reserved.
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| 8. |
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| 9. |
- Pershagen, Elias
(author)
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Development and Multicolor Imaging Applications of Lanthanide-Based Luminescent Probes
- 2014
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Doctoral thesis (other academic/artistic)abstract
- The study of biological analytes in their native environment is a major challenge for biochemistry and molecular biology. Luminesce spectroscopy is well suited for this task due to its non-invasiveness, high spatial and temporal resolution, and high signal to noise ratio. This thesis describes the development and applications of Ln-based luminescent probes for detecting small molecules and enzymes. Specifically the probes presented are based on coumarin sensitizers coupled to a DO3A chelated LnIII center. The 1st generation of these probes employ 7-OH coumarins, caged at the 7-O position (Chapter 2). By use of p-pinacolatoboron benzyl or p-methoxybenzyl cages, this design allowed the construction of ratiometric EuIII-based probes capable of detecting the reactive oxygen species H2O2, NO and ONOO−.The second and third part of the thesis describes a further improvement of the design (Chapters 3 and 4). By employing caged coumarin precursors EuIII and TbIII-based probes were developed for a variety of different analytes (F−, Pd0, H2O2, β-galactosidase, β-glucosidase, α-mannosidase and phosphatase). Most of these probes displayed excellent turn-on responses when treated with their respective analytes. Furthermore they could be used for detecting multiple analytes simultaneously (Chapter 4). By use of one Eu-based and another Tb-based probe, the simultaneous detection of two analytes was possible. This could further be extended to simultaneous three analyte detection by the additional employment of an organic coumarin-based probe.The last part of the thesis (Chapter 5) describes protocols for the rapid and efficient access to triazole-linked lanthanide-antenna complexes by use of the copper-catalyzed azide-alkyne cycloaddition reaction. For robust substrates, microwave heating at 100 °C enabled rapid (15-60 min) access to various lanthanide complexes, which could be isolated via simple precipitation. Using these conditions pure bi- and tri-homometallic lanthanide complexes could be prepared. A second protocol, for substrates carrying sensitive functionalities was also developed. The application of catalytic amounts of CuOAc, BimPy2 ligand, and a large excess of NaAsc afforded a variety of lanthanide complexes, among them caged responsive probes, in moderate to good yields.
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| 10. |
- Pershagen, Elias, et al.
(author)
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Europium-based turn-on bioconjugatable luminescent probe for detecting H2O2 in live cells.
- 2011
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In: Abstracts of Papers, 242<sup>nd</sup> ACS National Meeting & Exposition, Denver, CO, United States, August 28-September 1, 2011.
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Conference paper (other academic/artistic)abstract
- A Europium-based turn-on bioconjugatable luminescent probe for detecting hydrogen peroxide in live cells is presented. The probe relies on a chemoselective boronate-to-phenol switch in response to hydrogen peroxide, resulting in an enhanced lanthanide sensitization. Excitation can be performed by visible light. Bioconjugation is achived by Cu(I) catalyzed azide-alkyne cycloaddn.
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