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232 results on '"Iggo, Jonathan A."'

10. Thiazolide Prodrug Esters and Derived Peptides: Synthesis and Activity

Author

Stachulski, Andrew V., primary, Rossignol, Jean-Francois, additional, Pate, Sophie, additional, Taujanskas, Joshua, additional, Iggo, Jonathan A., additional, Aerts, Rudi, additional, Pascal, Etienne, additional, Piacentini, Sara, additional, La Frazia, Simone, additional, Santoro, M. Gabriella, additional, van Vooren, Lieven, additional, Sintubin, Liesje, additional, Cooper, Mark, additional, Swift, Karl, additional, and O’Neill, Paul M., additional

Published
2023
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14. Modular synthesis of bicyclic twisted amides and anilines.

Author

Hindle, Alexandra, Baj, Krzysztof, Iggo, Jonathan A., Cox, Daniel J., Pask, Christopher M., Nelson, Adam, and Marsden, Stephen P.

Subjects
ANILINE, HYDROAMINATION, RING formation (Chemistry), AMIDES, AMINATION, NITROGEN
Abstract

Bridged amides and anilines display interesting properties owing to perturbation of conjugation of the nitrogen lone-pair with the adjacent π-system. A convergent approach to diazabicyclic scaffolds which contain either twisted amides or anilines is described, based on the photocatalysed hydroamination of cyclic enecarbamates and subsequent cyclisation. The modular nature of the synthesis allows for variation of the degree of 'twist' and hence the properties of the amides and anilines. [ABSTRACT FROM AUTHOR]

Published
2023
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19. Synthesis and Structures of 1,1′,2-Tribromoferrocene, 1,1′,2,2′-Tetrabromoferrocene, 1,1′,2,2′-Tetrabromoruthenocene: Expanding the Range of Precursors for the Metallocene Chemist’s Toolkit

Author

Butler, Ian R., primary, Beaumont, Michael, additional, Bruce, Michael I., additional, Zaitseva, Natalia N., additional, Iggo, Jonathan A., additional, Robertson, Craig, additional, Horton, Peter N., additional, and Coles, Simon J., additional

Published
2021
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24. Efficient pKaDetermination in a Nonaqueous Solvent Using Chemical Shift Imaging

Author

Schenck, George, Baj, Krzysztof, Iggo, Jonathan A., and Wallace, Matthew

Abstract

pKais an important property of a molecule which impacts many fields, such as drug design, catalysis, reactivity, and environmental toxicity. It is often necessary to measure pKain nonaqueous media due to the poor solubility of an analyte in water, for example, many compounds of pharmaceutical interest. Although NMR methods to measure pKain water are well established, determining pKain organic solvents is laborious and problematic. We present an efficient one-shot method to determine the pKaof an analyte in an organic solvent in a single measurement. Diffusion of an acid into a basic solution of the analyte and a set of pH indicators establishes a pH gradient in the NMR tube. The chemical shift of a pH sensitive resonance of the analyte and the pH of the solution are then determined simultaneously as a function of position along the pH gradient by recording a chemical shift image of the NMR tube. The pKaof the analyte is then determined using the Henderson–Hasselbalch equation. The method can be implemented in any laboratory with a gradient equipped NMR high-field spectrometer and is demonstrated for a range of pharmaceutical compounds and inorganic phosphazene bases.

Published
2022
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29. Probing the surface chemistry of self-assembled peptide hydrogels using solution-state NMR spectroscopy

Author

Wallace, Matthew, Iggo, Jonathan A., and Adams, Dave J.

Abstract

The surface chemistry of self-assembled hydrogel fibres – their charge, hydrophobicity and ion-binding dynamics – is recognised to play an important role in determining how the gels develop as well as their suitability for different applications. However, to date there are no established methodologies for the study of this surface chemistry. Here, we demonstrate how solution-state NMR spectroscopy can be employed to measure the surface chemical properties of the fibres in a range of hydrogels formed from N-functionalised dipeptides, an effective and versatile class of gelator that has attracted much attention. By studying the interactions with the gel fibres of a diverse range of probe molecules and ions, we can simultaneously study a number of surface chemical properties of the NMR invisible fibres in an essentially non-invasive manner. Our results yield fresh insights into the materials. Most notably, gel fibres assembled using different tiggering methods bear differing amounts of negative charge as a result of a partial deprotonation of the carboxylic acid groups of the gelators. We also demonstrate how chemical shift imaging (CSI) techniques can be applied to follow the formation of hydrogels along chemical gradients. We apply CSI to study the binding of Ca2+ and subsequent gelation of peptide assemblies at alkaline pH. Using metal ion-binding molecules as probes, we are able to detect the presence of bound Ca2+ ions on the surface of the gel fibres. We briefly explore how knowledge of the surface chemical properties of hydrogels could be used to inform their practical application in fields such as drug delivery and environmental remediation.

Published
2017

30. Hydrogen-bonding-promoted oxidative addition and regioselective arylation of olefins with aryl chlorides

Author

Jiwu Ruan, Iggo, Jonathan A., Berry, Neil G., and Jianliang Xiao

Subjects
Olefins -- Structure, Olefins -- Chemical properties, Arylation -- Analysis, Ethylene glycol -- Chemical properties, Hydrogen bonding -- Analysis, Oxidation-reduction reaction -- Analysis, Palladium -- Chemical properties, Chemistry
Abstract

The first, general and highly efficient catalyst system is developed that has allowed a wide range of activated and unactivated aryl chlorides to couple regioselectively with olefins. Ethylene glycol has played a double role in the arylation, which has facilitated oxidative addition and has promoted the subsequent dissociation of chloride from Pd(II) to produce a cationic Pd(II)-olefin species.

Published
2010

31. Direct acylation of aryl bromides with aldehydes by palladium catalysis

Author

Jiwu Ruan, Saidi, Ourida, Iggo, Jonathan A., and Jianliang Xiao

Subjects
Aldehydes -- Chemical properties, Aldehydes -- Structure, Palladium -- Chemical properties, Palladium -- Structure, Aromatic amines -- Chemical properties, Aromatic amines -- Structure, Acylation -- Analysis, Chemistry
Abstract

An efficient protocol is developed for the direct acylation of aryl bromides with various aldehydes, thus obtaining alkyl aryl ketones in good yields. The reaction has involved cocatalysis of palladium and amine.

Published
2008

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