| 1. |
- Bharate, Jaideep B., et al.
(author)
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K2S2O8-mediated coupling of 6-amino-7-aminomethyl-thiazolino-pyridones with aldehydes to construct amyloid affecting pyrimidine-fused thiazolino-2-pyridones
- 2021
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In: Organic and biomolecular chemistry. - : The Royal Society of Chemistry. - 1477-0520 .- 1477-0539. ; 19:44, s. 9758-9772
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Journal article (peer-reviewed)abstract
- We herein present the synthesis of diversely functionalized pyrimidine fused thiazolino-2-pyridones via K2S2O8-mediated oxidative coupling of 6-amino-7-(aminomethyl)-thiazolino-2-pyridones with aldehydes. The developed protocol is mild, has wide substrate scope, and does not require transition metal catalyst or base. Some of the synthesized compounds have an ability to inhibit the formation of Amyloid-β fibrils associated with Alzheimer's disease, while others bind to mature amyloid-β and α-synuclein fibrils.
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| 2. |
- Dhillon, Prakriti, et al.
(author)
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Diyne-steered switchable regioselectivity in cobalt(ii)-catalysed C(sp(2))-H activation of amides with unsymmetrical 1,3-diynes
- 2023
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In: Organic and biomolecular chemistry. - : Royal Society of Chemistry. - 1477-0520 .- 1477-0539. ; 21:9, s. 1942-1951
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Journal article (peer-reviewed)abstract
- The regiochemical outcome of a cobalt(ii) catalysed C-H activation reaction of aminoquinoline benzamides with unsymmetrical 1,3-diynes under relatively mild reaction conditions can be steered through the choice of diyne. The choice of diyne provides access to either 3- or 4-hydroxyalkyl isoquinolinones, paving the way for the synthesis of more highly elaborate isoquinolines.
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| 3. |
- D'Imperio, Nicolas, et al.
(author)
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E,Z-Selectivity in the reductive cross-coupling of two benzaldehydes to stilbenes under substrate control
- 2020
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In: Organic & Biomolecular chemistry. - : Royal Society of Chemistry (RSC). - 1477-0520 .- 1477-0539. ; 18, s. 6171-6179
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Journal article (peer-reviewed)abstract
- Unsymmetrical E- and Z-stilbenes can be synthesized from two differently substituted benzaldehydes in a MesP(TMS)Li-promoted reductive coupling sequence. Depending on the order of addition of the two coupling partners, the same olefin can be produced in either E- or Z-enriched form under identical reaction conditions. A systematic study of the correlation between the stereochemical outcome of the reaction and the substitution pattern at the two aldehydes is presented. The results can be used as guidelines to predict the product stereochemistry.
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| 4. |
- Hansen, Nicolai S.B., et al.
(author)
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Development and mechanistic investigation of the dehydrogenation of alcohols with an iron(iii) salen catalyst
- 2023
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In: Organic and biomolecular chemistry. - : Royal Society of Chemistry (RSC). - 1477-0520 .- 1477-0539. ; 21:23, s. 4794-4800
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Journal article (peer-reviewed)abstract
- The iron(iii) salen complex (R,R)-N,N′-bis(salicylidene)-1,2-cyclohexanediamineiron(iii) chloride has been developed as a catalyst for the acceptorless dehydrogenation of alcohols. The complex catalyzes the direct synthesis of imines in good yields from different primary alcohols and amines with the liberation of hydrogen gas. The mechanism has been investigated experimentally with labelled substrates and theoretically with density functional theory calculations. In contrast to the corresponding manganese(iii) salen-catalyzed dehydrogenation, it has not been possible to identify a homogeneous catalytic pathway with the iron complex. Instead, poisoning experiments with trimethylphosphine and mercury indicated that the catalytically active species are heterogeneous small iron particles.
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| 5. |
- Hartmann, Rafael W., et al.
(author)
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The Wittig Bioconjugation of Maleimide Derived, Water Soluble Phosphonium Ylides to Aldehyde-Tagged Proteins
- 2021
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In: Organic and biomolecular chemistry. - : Royal Society of Chemistry. - 1477-0520 .- 1477-0539. ; 19:47, s. 10417-10423
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Journal article (peer-reviewed)abstract
- Herein we disclose the transformation of maleimides into water-soluble tris(2-carboxyethyl)phosphonium ylides and their subsequent application in the bioconjugation of protein- and peptide-linked aldehydes. The new entry into Wittig bioconjugate chemistry proceeds under mild conditions and relies on highly water soluble reagents, which are likely already part of most biochemists’ inventory.
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| 6. |
- Hartmann, R. W., et al.
(author)
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The Wittig bioconjugation of maleimide derived, water soluble phosphonium ylides to aldehyde-tagged proteins
- 2021
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In: Organic and biomolecular chemistry. - : Royal Society of Chemistry (RSC). - 1477-0520 .- 1477-0539. ; 19:47, s. 10417-10423
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Journal article (peer-reviewed)abstract
- Herein we disclose the transformation of maleimides into water-soluble tris(2-carboxyethyl)phosphonium ylides and their subsequent application in the bioconjugation of protein- and peptide-linked aldehydes. The new entry into Wittig bioconjugate chemistry proceeds under mild conditions and relies on highly water soluble reagents, which are likely already part of most biochemists' inventory.
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| 7. |
- Kaszás, Tímea, et al.
(author)
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Coupling ofN-tosylhydrazones with tetrazoles : synthesis of 2-β-d-glycopyranosylmethyl-5-substituted-2H-tetrazole type glycomimetics
- 2021
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In: Organic and Biomolecular Chemistry. - : Royal Society of Chemistry (RSC). - 1477-0520 .- 1477-0539. ; 19:3, s. 605-618
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Journal article (peer-reviewed)abstract
- Coupling reactions ofO-peracylated 2,6-anhydro-aldose tosylhydrazones (C-(β-d-glycopyranosyl)formaldehyde tosylhydrazones) with tetrazoles were studied under metal-free conditions using thermic or microwave activation in the presence of different bases. The reactions proved highly regioselective and gave the corresponding, up-to-now unknown 2-β-d-glycopyranosylmethyl-2H-tetrazoles in 7-67% yields. The method can be applied to get new types of disaccharide mimetics, 5-glycosyl-2-glycopyranosylmethyl-2H-tetrazoles, as well. Galectin binding studies withC-(β-d-galactopyranosyl)formaldehyde tosylhydrazone and 2-(β-d-galactopyranosylmethyl)-5-phenyl-2H-tetrazole revealed no significant inhibition of any of these lectins.
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| 8. |
- Kathiravan, Suppan, et al.
(author)
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Electrochemical rhodium catalysed alkyne annulation with pyrazoles through anodic oxidation - a metal oxidant/additive free methodology
- 2023
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In: Organic and biomolecular chemistry. - : Royal Society of Chemistry. - 1477-0520 .- 1477-0539. ; 21:9, s. 2024-2033
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Journal article (peer-reviewed)abstract
- Pyrazole and its derivatives are important azole heteroarenes prevalent in pharmaceutical compounds and have been used as ligands for protein binding, making them valuable targets for synthetic applications. Herein we disclose an electrochemical intermolecular C-H/N-H oxidative annulation of 2-phenylpyrazoles with alkynes using a rhodium(iii) redox regime without any external metal oxidants in a water compatible solvent system. Both symmetrical and unsymmetrical alkynes were shown to be compatible with the optimized conditions.
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| 9. |
- Long, Mark, et al.
(author)
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Synthesis of type 1 Lewis b hexasaccharide antigen structures featuring flexible incorporation ofl-[U-C-13(6)]-fucose for NMR binding studies
- 2020
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In: Organic and biomolecular chemistry. - : Royal Society of Chemistry (RSC). - 1477-0520 .- 1477-0539. ; 18:23, s. 4452-4458
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Journal article (peer-reviewed)abstract
- While(13)C-labelled proteins are common tools in NMR studies, lack of access to(13)C-labelled carbohydrate structures has restricted their use.l-Fucose is involved in a wide range of physiological and pathophysiological processes in mammalian organisms. Here,l-[U-C-13(6)]-Fuc labelled type I Lewis b (Le(b)) structures have been synthesised for use in NMR binding studies with the Blood-group Antigen Binding Adhesin (BabA), a membrane-bound protein from the bacteriumHelicobacter pylori. As part of this work, an efficient synthesis of a benzylatedl-[U-C-13(6)]-Fuc thioglycoside donor froml-[U-C-13(6)]-Gal has been developed. The design and synthesis of an orthogonally protected tetrasaccharide precursor enabled controlled introduction of one or two(13)C-labelled or non-labelled fucosyl residues prior to global deprotection. NMR analysis showed that it is straightforward to assign the anomeric centres as well as the H-5 positions to the individual fucosyl residues which are relevant for NMR binding studies.
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| 10. |
- Manso, Mads, 1991, et al.
(author)
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Establishing linear-free-energy relationships for the quadricyclane-to-norbornadiene reaction
- 2020
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In: Organic and Biomolecular Chemistry. - : Royal Society of Chemistry (RSC). - 1477-0539 .- 1477-0520. ; 18:11, s. 2113-2119
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Journal article (peer-reviewed)abstract
- The kinetics of the thermal quadricyclane-to-norbornadiene (QC-to-NBD) isomerization reaction was studied for a large selection of derivatives where the one NBD double bond contains a cyano and aryl substituent of either electron-withdrawing or -donating character. While the kinetics data did not satisfy a linear-free-energy-relationship for all the derivatives based on Hammett sigma values, we found individual linear relationships for derivatives containing either electron-withdrawing or electron-donating para substituents on the aryl group; with the most electron-witdrawing substituent in the one series and with the most electron-donating substituent in the other providing the fastest reaction (corresponding to opposite slopes of the Hammett plots). All data were well described, however, by a linear relationship when using Creary radical values; the correlation could be slightly improved by using a combination of sigma and values (used in ratio of 0.104 : 1). The results imply a combination of polar and free radical effects for the isomerization reaction of this specific class of derivatives, with the latter playing the most significant role. The NBD derivatives were prepared by Diels-Alder cycloaddition reactions between cyclopentadiene and 3-arylpropiolonitriles, and in the case of bromophenyl derivatives further cyanation and Sonogashira coupling reactions were performed.
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