Andrew J Clark

Andrew J Clark
The University of Warwick · Department of Chemistry

PhD

About

131
Publications
5,695
Reads
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2,371
Citations
Introduction
Copper mediated radical reactions in organic synthesis. Renewable materials using nitrile oxides. Asymmetric synthesis using atropisomeric enamides
Additional affiliations
October 2020 - October 2020
The University of Warwick
Position
  • Deputy Pro-Vice Chancellor (Education Policy)
May 2017 - present
The University of Warwick
Position
  • Professor (Full)
October 1993 - present
The University of Warwick
Description
  • Associate professor in synthesis Director of undergraduate studies
Education
October 1986 - January 2000
King's College London
Field of study
  • Chemistry
October 1983 - July 1986
King's College London
Field of study
  • Chemistry

Publications

Publications (131)
Article
Full-text available
Ligands bearing soft donors including N- and S- have found applications in selective metal recovery due to the ability to preferentially bind soft acceptors like Ag⁺. Herein, N-(2-((4-vinylbenzyl)thio)ethyl)acetamide (L) bearing potential Ag⁺-selective N- and S-donors was prepared in a 76% yield under mild conditions. Reaction of L with silver perc...
Article
Magnetic nanoparticles embody a valuable suite of technologies for the selective recovery of metals from the aqueous phase owing to their high surface area, the ease of recovery using an externally applied magnetic field and their ability to be custom designed. Ligands bearing sulfur (S-) and nitrogen (N-) donors are suited for such functionalizati...
Article
Solvent or liquid–liquid extraction represents a highly valuable technique for the selective recovery of metals from the aqueous phase due to the ease of operation and short turnaround times. Ligands bearing soft donor atoms including nitrogen and sulfur are ideal candidates for selective silver recovery due to their preference for silver binding....
Article
Full-text available
Surface functionalized magnetic nanoparticles represent a potentially highly valuable new suite of technologies for the selective recovery of metals from the aqueous phase, due to their ability to be manipulated and then recovered using an externally applied magnetic field. Ionic liquids are ideal candidates for such surface functionalization for a...
Preprint
Ligands bearing S - and N - donors are an important class of extractants with demonstrated efficiency and selectivity for Ag<sup>+</sup> extraction over metals with similar chemistries. However, the synthesis of some of these ligands can be complicated and low yielding. Here, we report the synthesis of a novel ligand - N -(2-((4-vinylbenzyl)thio)et...
Preprint
a>Surface functionalized magnetic nanoparticles represent a potentially highly valuable tool for the selective recovery of metals from the aqueous phase, due to their ability to be manipulated and then recovered using an externally applied magnetic field. Ionic liquids are ideal candidates for such surface functionalization for a range of reasons,...
Preprint
Unsubstituted and gem-diethyl substituted malonamide derivatives, bearing benzylthio arms were prepared in moderate to high yields at room temperature. It was observed that electronics effects at the 4-aryl position in the malonamide derivatives had a significant effect on the selectivity, but little effect on silver(I) extraction efficiency measur...
Article
BACKGROUND: Development of circular economy requires significant advances in the technologies for valorisation of waste, as waste becomes new feedstock. Food waste is a particularly important feedstock, containing large variation of complex chemical functionality. Although most food waste sources are complex mixtures, waste from food processing, no...
Article
Full-text available
The aim of this study was to investigate the application of grapeseed oil, a waste product from the wine industry, as a renewable feedstock to make polyesters and to compare the properties of these materials with those derived from soybean and rapeseed oils. All three oils were epoxidized to give renewable epoxy monomers containing between 3.8 and...
Article
Full-text available
BACKGROUND Development of circular economy requires significant advances in the technologies for valorisation of waste, as waste becomes new feedstock. Food waste is a particularly important feedstock, containing large variation of complex chemical functionality. Although most food waste sources are complex mixtures, waste from food processing, no...
Article
Drug reprofiling is emerging as an effective paradigm for discovery of cancer treatments. Herein, an antipsychotic drug is immobilised using the Magic Tag® chemical genomics tool and screened against a T7 bacteriophage displayed library of polypeptides from Drosophila melanogaster, as a whole genome model, to uncover an interaction with a section o...
Article
Generally, pyrrolidinones are obtained as products whereas in case of substrate (VI) azetidinones are obtained.
Article
The barrier to rotation around the N-alkenyl bond of thirty-eight N-alkenyl-N-alkyl acetamide derivatives was measured (activation free energy rotation varied between <8.0 to 31.0 kcal mol-1). The most important factor in controlling the rate of rotation was the level of alkene substitution, followed by the size of the nitrogen substituent and fina...
Article
Copper mediated cyclization of activated 1-substituted enamides occurs via a 5-endo radical-polar crossover process. Trichloroacetyl derivatives can undergo further reactions post cyclization (elimination of HCl or dimerization potentially via copper carbenoid intermediates). Reaction of α-halo trienamides derived from β-ionone furnish either β- or...
Article
Efficient 5-exo-trig atom-transfer radical cyclisation of 13 unsaturated α-halogeno amides mediated by Cu0 (copper wire) with tripyridylmethanimine ligand (TPMA; 1 mol-%) in a mixed solvent of EtOAc/EtOH (3:1) is reported (89-98%), with recycling of the copper wire. A substantial improvement in conversion and selectivity was obtained when Na2CO3 (5...
Article
Atom transfer radical cyclization (ATRC) is a powerful technique to prepare functionalized 4–10 membered ring systems using transition metal catalysts. In this review recent advances in the use of copper complexes are described. In particular the effect of different ligands on reactivity, selectivity and product outcome are illustrated with applica...
Article
Several organic soluble N-based ligands and their copper complexes were firstly investigated as catalysts to depolymerise organosolv lignin in the organic solvent, dimethylformamide (DMF) and an ionic liquid (1-ethyl-3-methylimidazolium xylenesulfonate, [emim][ABS]). The results of screening depolymerisation reactions in DMF and [emim][ABS] showed...
Article
The N-arylsulfonyl group, which is the best and most useful cyclization auxiliary for the transition-metal-catalyzed atom transfer radical cyclization (ATRC) of N-allyl-α-polychloroamides, can be effectively removed from the target γ-lactams by using H2SO4–HOAc, without impairing the halogen functions. The reaction involves H+ attack on the aromati...
Article
Composites offer high strength and stiffness at a lower density compared to other structural materials, therefore are of growing use to a variety of lightweight structures in order to reduce emissions and improve performance. However, traditional composites have the highest embodied carbon content of all engineering materials with limited methods o...
Article
Full-text available
The Lewis acid ring-opening of epoxidized vegetable oils (EVO's) in the presence of tetrahydrofuran (THF) gives rise to polyether polyol co-polymers p(THF-stat-EVO). The effect of Lewis acid, vegetable oil substrate (epoxidised methyloleate EMO, epoxidised cocoa butter ECB, and epoxidised palm oil EPO) and conditions (concentration, temperature and...
Article
A principle of biorefining is extended to medicinal plants with the view of developing a more sustainable business model for biomass producers and extractors. This is demonstrated for Artemisia annua L. currently cultivated or harvested in the wild for extraction of a single compound, artemisinin, comprising on average 1 wt% dry weight of the plant...
Article
Magic Tag® immobilisation of bioactive molecules coupled with bacteriophage display, followed by an ELISA assay, provides a protocol that can probe interactions of drugs with putative products of alternative initiation of translation as exemplified by the binding of immobilised flecainide to protein products of genes linked to sudden cardiac death.
Article
The cyclisation of N-allyl-N-substituted-α-polychloroamides is efficiently obtained through a copper-catalysed activators regenerated by electron transfer–atom transfer radical cyclisation process, with a metal load of only 0.5 mol%. The redox catalyst is introduced in its inactive form as copper(II) chloride/[nitrogen ligand] complex, and continuo...
Article
The 4-exo and 5-exo-trig atom-transfer cyclizations of 1, 8a-e, 9, 12, and 13 can be mediated with as little as 0.05 mol % of Cu(TPMA)SO(4)·5H(2)O in the presence of 2.5 mol % of borohydride salts in 10 min at room temperature in air. This formal "activators generated by electron transfer" (AGET) procedure utilizes a cheap and oxidatively stable co...
Article
This work aims to recover lignocellulosic waste in an environmentally friendly process, as an alternative to the energy-intensive technologies: steam explosion, subcritical and/or supercritical water treatment, decomposition through pyrolisis, etc. The study assesses the optimum of potentially valuable compounds from straw degraded by the fungus Pl...
Article
A Dynamic Nuclear Polarisation (DNP) enhanced solid-state Magic Angle Spinning (MAS) NMR spectrometer operating at 6.7 T is described and demonstrated. The 187 GHz TE(13) fundamental mode of the FU CW VII gyrotron is used as the microwave source for this magnetic field strength and 284 MHz (1)H DNP-NMR. The spectrometer is designed for use with mic...
Article
Barriers to rotation of the N-alkenyl bond in a series of N-cycloalkenyl-N-benzyl acetamide derivatives have been measured in different solvents by variable-temperature NMR experiments. The barriers range from 9.7 to 14.2 kcal/mol, depending on substituents on the acetamide acyl group. Polar solvents such as chloroform and methanol increase the bar...
Article
Full-text available
We demonstrate the expected preference of an immobilised oligosaccharide Man(9)(GlcNAc)(2) upon a 96-well photochemical array, for its known receptor, the cell-surface lectin Dendritic Cell-Specific ICAM3 Grabbing Nonintegrin (DC-SIGN) when compared to immobilised competing monosaccharides.
Article
Using an electrospinning technique, polymer materials have been spun using electrostatic potential to create a fiber mat. To develop the electrospinning opportunities available for practical applications, it is important that a full understanding of process parameters is achieved. These fundamental principles will form the initial framework of futu...
Article
The cyclisation of aryl radicals derived by treatment of aryl halides (1a), (1b), (4), (7a), (7b), and (10)with tri-n-butyltin hydride has been investigated.
Article
Reaction of N-butyl-N-(2-bromo-2-methylpropionyl)-arylsulfonamides with CuBr/tripyridylamine leads to amidyl radicals via 1,4-aryl migration with concomitant loss of SO(2), which can further undergo cyclisation to oxindoles or reduction to amides with the ratio dependent upon the temperature and solvent utilised.
Article
Reaction of N-alkyl-N-arylsulfonyl-2-halo-propionamides with pentamethyldiethylenetriamine and either CuBr or CuCl leads to 2-aryl propionamides via initial radical generation, 1,4-aryl migration with loss of SO2 and reduction of the intermediate amidyl radical in 40–99% yields.
Article
Reaction of N-alkyl-N-(trichloroacetyl)arylsulfonamides with CuCl/amines leads to N-alkyl-N-(dichloroacetyl)-arylsulfonamides via reduction or N-alkyl-aryldichloroacetamides via 1,4-aryl migration with loss of SO2. The ratio of reduction to aryl migration is dependent upon the temperature and the ligand utilised. Along with amide bond hydrolysis th...
Article
Barriers to rotation of the N-alkenyl bond in a series of N-cycloalkenyl-N-benzyl alpha-haloacetamide derivatives have been measured by variable-temperature NMR experiments. The barriers range from 10 to 18 kcal/mol, depending on ring size and on substituents on the cycloalkene and the amide. The observed trends aid in the design of substituent com...
Article
Polyurethanes (PUs), produced by cross-linking with a di-isocyanate hydroxylated vegetable oils (rapeseed and sunflower), have been examined from the viewpoints of their thermal degradation and their materials properties, and how both of these aspects are influenced both by the addition of TiO2 filler and by UV irradiation. The thermal decompositio...
Article
UV-induced photodegradation has been studied of films of polyurethanes synthesised from (renewable) vegetable materials, namely rapeseed and sunflower oils. The techniques utilised were principally IR and UV-visible spectroscopy. UV(B)-photolysis of the cured films gave rise to IR bands in the carbonyl region at ca 1706 cm⁻¹ and a UV band at 310 nm...
Article
We have shown that it is possible to mediate a range of 5-exo trig and 5-exo dig atom transfer radical cyclisations of bromoacetamides using 0.1–1mol% CuBr or CuBr2 in conjunction with 0.1–1mol% tri(pyridin-2-ylmethyl)amine and 10mol% AIBN. This equates to a 30–300-fold reduction in the amount of catalyst previously reported for these reactions and...
Article
The use of plant oils as industrial feedstocks can often be hampered by their lack of optimization towards a particular process, as well as their development being risky; growing suitable volumes of crops to test can take up to five years. To circumvent this, we aimed to discover a method that would mimic plant oil profiles in the laboratory, and s...
Article
The cover picture shows a view from the X-ray crystallographic structure of activating transcription factor, ATF4, showing its molecular surface in a coiled-coil dimer with C/EBPβ, depicted in red. The interaction of the sequence highlighted in green with salbutamol is uncovered by S. R. Ladwa et al. on p. 742 ff. using the magic tag® chemical geno...
Article
Full-text available
A composite material consisting of hydroxide-modified hemp fibres and euphorbia resin was produced. The composites were tested in tension, short-beam interlaminar shear stress and in impact. There was an increase in the tensile strength and modulus for resins with high-hydroxyl-group based composites. Similar results were obtained for interlaminar...
Article
Full-text available
We show that the use of multiple photochemistries is necessary to ensure diverse immobilisation of small molecules for binding of polypeptides using phage display and antibody libraries.
Article
Reaction of 2-substituted dienamides with catalytic amounts of copper halide/tripyridylamine (TPA) furnishes either 5-exo or 6-endo products with the outcome dependent upon the radical initiating unit. Reaction of 3-substituted dienamides produces beta-lactams via a 4-exo cyclization with termination of the reaction occurring via either halogen ato...
Article
Metadata is a valuable resource that, among other things, helps manage multiple changes to documents being produced by multiple authors collaborating together. These hidden properties are also of particular importance to forensic investigators who may well seek evidence linking individuals with knowledge of events or particular facts. But are we in...
Article
We prepare a biotinylated conjugate of the ubiquitous plant hormone (S)-(+)-abscisic acid via an acyl hydrazone linkage at the C4' position and demonstrate in vivo cleavage of the otherwise stable acyl hydrazone linkage using LC-MS2. As part of a wider chemical genomic study, biological activity of the conjugate was assessed using standard epiderma...
Article
Short and high-yielding syntheses of enantiomerically pure (S)-(+) and (R)-(-)-abscisic acid are described. The syntheses proceed through key intermediates that preferentially recrystallise as single diastereoisomers for each enantiomer. This route allows the preparation of either enantiomer of abscisic acid in ca. 30% overall yield, and as demonst...
Article
Novel surfaces derivatized with tertiary amine oxides have been prepared and tested for their ability to resist nonspecific protein adsorption. The oxidation of tertiary amines supported on triazine units was carried out using mCPBA to give a format allowing conjugation of biologically active ligands alongside them. Adsorption to these surfaces was...
Article
A practical and divergent synthesis of supported [1,3,5]-triazine dendritic molecules on Wang resin, PEGA resin, SynPhase™ Lanterns, and silica gel is described. The alkylamine linkers used allow derivatization with functionality for both synthetic (e.g., supported reagent and scavenger activity) and chemical biology applications. The use of suppor...
Article
A range of solid supported pyridinemethanimine 9-11 and polyamine 12-15 ligands have been prepared on silica, polystyrene, and JandaJel supports. The CuCl and CuBr complexes of these supported ligands have been used to assess both the effect of the ligand type and the nature of the support upon a representative range of copper-mediated atom transfe...
Chapter
IntroductionRearrangementsIntramolecular AdditionFragmentation, Recombination, and HomolysisAtom Abstraction ReactionsAddition ReactionsHomolytic SubstitutionReactivity EffectsStereoselectivity in Radical ReactionsRedox ReactionsRadical IonsPeroxides, Peroxyl, and Hydroxyl RadicalsBiological ChemistryReferences
Chapter
IntroductionRearrangementsIntramolecular AdditionFragmentation, Recombination, and HomolysisAtom Abstraction ReactionsAddition ReactionsHomolytic SubstitutionReactivity EffectsStereoselectivity in Radical ReactionsRedox ReactionsRadical IonsPeroxides, Peroxyl, and Hydroxyl RadicalsReactions of Biological Systems and Biologically Important Molecules...
Article
Treatment of malonyl derived O-acyl hydroxamic acid derivatives 10a–h with the phosphazene super base P-2-t-Bu 7 gives 2,3-dihydro-4-isoxazole carboxylic ester derivatives 11a–h. The rate and yield of the reaction is dependent upon the O-acyl substituent.
Article
[reaction: see text] Ceric ammonium nitrate mediates the oxidative 5-endo radical-polar crossover reactions of beta-enamide esters to give 5,5-C,O-disubstituted-gamma-lactams. Trapping of the intermediate cations leads to 5-hydroxy- or 5-alkoxy-gamma-lactams depending upon the reaction conditions. The methodology was used to synthesize the basic he...
Chapter
IntroductionRearrangementsIntramolecular AdditionFragmentation, Recombination, and HomolysisAtom Abstraction ReactionsHalogenationAddition ReactionsHomolytic SubstitutionReactivity EffectsStereoselectivity in Radical ReactionsRedox ReactionsRadical IonsPeroxides, Peroxyl, and Hydroxyl RadicalsReferences