| 1. |
- Agudo, I., et al.
(författare)
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Panning for gold, but finding helium: Discovery of the ultra-stripped supernova SN 2019wxt from gravitational-wave follow-up observations
- 2023
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 675
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Tidskriftsartikel (refereegranskat)abstract
- We present the results from multi-wavelength observations of a transient discovered during an intensive follow-up campaign of S191213g, a gravitational wave (GW) event reported by the LIGO-Virgo Collaboration as a possible binary neutron star merger in a low latency search. This search yielded SN 2019wxt, a young transient in a galaxy whose sky position (in the 80% GW contour) and distance (∼150 Mpc) were plausibly compatible with the localisation uncertainty of the GW event. Initially, the transienta's tightly constrained age, its relatively faint peak magnitude (Mi ∼ -16.7 mag), and the r-band decline rate of ∼1 mag per 5 days appeared suggestive of a compact binary merger. However, SN 2019wxt spectroscopically resembled a type Ib supernova, and analysis of the optical-near-infrared evolution rapidly led to the conclusion that while it could not be associated with S191213g, it nevertheless represented an extreme outcome of stellar evolution. By modelling the light curve, we estimated an ejecta mass of only ∼0.1 M·, with 56Ni comprising ∼20% of this. We were broadly able to reproduce its spectral evolution with a composition dominated by helium and oxygen, with trace amounts of calcium. We considered various progenitor channels that could give rise to the observed properties of SN 2019wxt and concluded that an ultra-stripped origin in a binary system is the most likely explanation. Disentangling genuine electromagnetic counterparts to GW events from transients such as SN 2019wxt soon after discovery is challenging: in a bid to characterise this level of contamination, we estimated the rate of events with a volumetric rate density comparable to that of SN 2019wxt and found that around one such event per week can occur within the typical GW localisation area of O4 alerts out to a luminosity distance of 500 Mpc, beyond which it would become fainter than the typical depth of current electromagnetic follow-up campaigns.
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| 2. |
- Phillips, S. D., et al.
(författare)
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Exploring the role of phosphorus substituents on the enantioselectivity of Ru-catalysed ketone hydrogenation using tridentate phosphine-diamine ligands
- 2011
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Ingår i: Catalysis Science and Technology. - : Royal Society of Chemistry (RSC). - 2044-4753 .- 2044-4761. ; 1:8, s. 1336-1339
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Tidskriftsartikel (refereegranskat)abstract
- Methods to produce a range of new phosphine-diamine ligands from phosphino-aldehydes have been developed and a hypothesis that larger P-substituents would increase the enantioselectivity towards the (S) isomer in Ru-catalysed ketone hydrogenation of acetophenone has been examined; the successful validation of this hypothesis is further evidence that the mechanism of these catalysts involves a secondary amine assisted reduction.
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| 3. |
- Lundin, Anna, et al.
(författare)
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Targeting Membrane-Bound Viral RNA Synthesis Reveals Potent Inhibition of Diverse Coronaviruses Including the Middle East Respiratory Syndrome Virus
- 2014
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Ingår i: Plos Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 10:5
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Tidskriftsartikel (refereegranskat)abstract
- Coronaviruses raise serious concerns as emerging zoonotic viruses without specific antiviral drugs available. Here we screened a collection of 16671 diverse compounds for anti-human coronavirus 229E activity and identified an inhibitor, designated K22, that specifically targets membrane-bound coronaviral RNA synthesis. K22 exerts most potent antiviral activity after virus entry during an early step of the viral life cycle. Specifically, the formation of double membrane vesicles (DMVs), a hallmark of coronavirus replication, was greatly impaired upon K22 treatment accompanied by near-complete inhibition of viral RNA synthesis. K22-resistant viruses contained substitutions in non-structural protein 6 (nsp6), a membrane-spanning integral component of the viral replication complex implicated in DMV formation, corroborating that K22 targets membrane bound viral RNA synthesis. Besides K22 resistance, the nsp6 mutants induced a reduced number of DMVs, displayed decreased specific infectivity, while RNA synthesis was not affected. Importantly, K22 inhibits a broad range of coronaviruses, including Middle East respiratory syndrome coronavirus (MERS-CoV), and efficient inhibition was achieved in primary human epithelia cultures representing the entry port of human coronavirus infection. Collectively, this study proposes an evolutionary conserved step in the life cycle of positive-stranded RNA viruses, the recruitment of cellular membranes for viral replication, as vulnerable and, most importantly, druggable target for antiviral intervention. We expect this mode of action to serve as a paradigm for the development of potent antiviral drugs to combat many animal and human virus infections.
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| 4. |
- Ten Broeke, M., et al.
(författare)
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Tricarbonyliron(0) complexes of bio-derived η4 cyclohexadiene ligands: An approach to analogues of oseltamivir
- 2015
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Ingår i: Journal of Organometallic Chemistry. - : Elsevier BV. - 0022-328X. ; 799-800, s. 19-29
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Tidskriftsartikel (refereegranskat)abstract
- We have prepared novel [η4] and [η5]+ tricarbonyliron complexes from an unusual enantiopure cyclohexadiene ligand that possesses a quaternary stereocentre; this in turn is prepared through biotransformation of an aromatic ring. The cyclohexadiene ligand initially possessed two hydroxyl groups, both of which could be substituted with other functionality by means of an overall [η4] → [η5]+ → [η4] → [η5]+ → [η4] sequence. From six novel tricarbonyliron complexes which have been prepared, three have been characterised by x-ray crystallography. The reaction sequence we describe is potentially of relevance to the synthesis of analogues of the anti-influenza drug oseltamivir. In addition, the failure of an attempted addition of a bulky nitrogen nucleophile to an [η5]+ complex sheds light on the limits of reactivity for such additions. Thus, two bulky nucleophiles which are each known to add successfully to unencumbered [η5]+ complexes seemingly cannot be added sequentially to adjacent positions on the cyclohexadiene ligand.
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| 5. |
- Bromfield, Karen M., 1976, et al.
(författare)
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An iron carbonyl approach to the influenza neuraminidase inhibitor oseltamivir
- 2007
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1364-548X .- 1359-7345. ; :30, s. 3183-3185
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Tidskriftsartikel (refereegranskat)abstract
- A novel synthetic route towards oseltamivir, an influenza neuraminidase inhibitor, has been achieved employing a cationic iron carbonyl complex, providing an alternate pathway with the potential to access diverse analogues.
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| 6. |
- Bromfield, Karen M., 1976, et al.
(författare)
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Synthetic applications of cationic iron and cobalt carbonyl complexes
- 2009
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Ingår i: Dalton Transactions. - 1477-9226 .- 1477-9234. ; :26, s. 5051-5061
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Tidskriftsartikel (refereegranskat)abstract
- Metal carbonyl stabilized cationic species react with a wide range of nucleophiles under mild conditions, and have thus found many synthetic applications. In this Perspective, we describe the utility of iron carbonyl dienyl cations in solution and solid phase parallel synthesis, and in the development of a new synthetic route towards oseltamivir phosphate (Tamiflu). We also discuss the solid phase version of the Nicholas reaction, employing cobalt carbonyl stabilized propargylic cations, and giving access to substituted alkynes.
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| 7. |
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| 8. |
- Johansson, M. J., et al.
(författare)
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Modular asymmetric synthesis of P-chirogenic beta-amino phosphine boranes
- 2008
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Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 73:12, s. 4458-4463
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Tidskriftsartikel (refereegranskat)abstract
- (Chemical Equation Presented) A short concise route to β- aminophosphine boranes is presented via the desymmetrization of prochiral phosphine boranes, forming P-chirogenic aldehydes that are rapidly transformed to the target compounds employing reductive amination under microwave irradiation. This sequence provides a modular route to P-chirogenic P,N ligands, and in addition, the intermediate aldehydes are versatile P-chiral building blocks for ligand design in general. An alternative pathway via the corresponding α-carboxyphosphines is also described. The ligands were subsequently evalutated in the asymmetric conjugate addition of diethylzinc to trans-β-nitrostyrene. © 2008 American Chemical Society.
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| 9. |
- Ljungdahl, Natalie, 1976, et al.
(författare)
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Solid phase organometallic chemistry
- 2007
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Ingår i: Combinatorial Chemistry on Solid Supports. ; 278, s. 89-134
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Tidskriftsartikel (refereegranskat)abstract
- This review covers recent results in the area of solid phase organometallic chemistry during the period 2000-2006. The focus is on carbon-carbon bond formation, but other aspects of organometallic reactions are also discussed. This includes the use of metal complexes as linkers, synthesis of biologically active compounds and complex natural product analogues, development of diversifying cleavage strategies, and testing the stability of new linkers and polymers under different reaction conditions. In many cases a direct comparison has been made between solid phase and solution phase chemistry. Thus, the advantages of performing reactions on polymer-supported substrates in terms of avoiding side reactions and facilitating product/metal separation are highlighted.
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| 10. |
- Ruda, M, et al.
(författare)
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Solid-phase synthesis of a 6-phenylquinolin-2(1H)-one library directed toward nuclear hormone receptors
- 2005
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Ingår i: Journal of combinatorial chemistry. - : American Chemical Society (ACS). - 1520-4766 .- 1520-4774. ; 7:4, s. 567-573
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Tidskriftsartikel (refereegranskat)abstract
- A library of 6-phenylquinolin-2(1H)-ones with diversity at position I and the ortho, meta, and para positions of the pendant phenyl ring has been synthesized using solid-phase parallel synthetic techniques. A key step in the synthesis of the library is a tandem alkylation cleavage in which diversity can be introduced at position 1 simultaneously to the cleavage from the resin. The yields of this step were significantly improved over what has previously been reported by addition of cesium carbonate to scavenge the acid that is formed during the reaction. Furthermore, we have shown that the solid support linkage is tolerant to Suzuki coupling and etherification reaction conditions and that selective cleavage of the linkage can take place in the presence of esters. The resulting 6-phenylquinolin-2(1H)-one library was screened against a panel of nuclear hormone receptors (androgen, estrogen alpha and beta isoforms, glucocorticoid, mineralocorticoid, and progesterone). Certain members of this library display moderate affinity for several of these receptors, and consequently, the 6-phenylquinolin-2(1H)-one core of the library may be considered a privileged structure for nuclear hormone receptors. In contrast, other members of the library display high selectivity for a particular receptor. The highest affinity ligand (9{2,1,1}) possesses an affinity of 330 nM for the androgen receptor, whereas the most selective ligand (9{2,4,1}) displays an affinity of 900 nM for the androgen receptor and a selectivity of 140-fold over the next highest affinity receptor.
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