Publications by authors named "Jonathan Burton"

The sealutomicins are a family of anthraquinone antibiotics featuring an enediyne (sealutomicin A) or Bergman-cyclized aromatic ring (sealutomicins B-D). Herein we report the development of an enantioselective organocatalytic method for the synthesis of dihydroquinolines and the use of the developed method in the total synthesis of sealutomicin C which features a transannular cyclization of an aryllithium onto a γ-lactone as a second key step.

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Eukaryotes produce a large number of cytochrome P450s that mediate the synthesis and degradation of diverse endogenous and exogenous metabolites. Yet, most of these P450s are uncharacterized and global tools to study these challenging, membrane-resident enzymes remain to be exploited. Here, we applied activity profiling of plant, mouse and fungal P450s with chemical probes that become reactive when oxidized by P450 enzymes.

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Glutathione transferases (GSTs) represent a large and diverse enzyme family involved in the detoxification of small molecules by glutathione conjugation in crops, weeds and model plants. In this study, we introduce an easy and quick assay for photoaffinity labeling of GSTs to study GSTs globally in various plant species. The small-molecule probe contains glutathione, a photoreactive group and a minitag for coupling to reporter tags via click chemistry.

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Dried blood spot (DBS) sample collection has been suggested as a less invasive, cheaper and more convenient alternative to venepuncture, which requires trained personnel, making it a potentially viable approach for self-collection of blood on a large scale. We examine whether participants in a longitudinal survey were willing to provide a DBS sample in different interview settings, and how resulting cardiovascular risk biomarkers compared with those from venous blood to calculate clinical risk. Participants of the Understanding Society Innovation Panel, a representative sample of UK households, were randomly assigned to three modes of interview.

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Background: While medical studies generally provide health feedback to participants, in observational studies this is not always the case due to logistical and financial difficulties, or concerns about changing observed behaviours. However, evidence suggests that lack of feedback may deter participants from providing biological samples. This paper investigates the effect of offering feedback of blood results on participation in biomeasure sample collection.

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The control of tetrahedral carbon stereocentres remains a focus of modern synthetic chemistry and is enabled by their configurational stability. By contrast, trisubstituted nitrogen, phosphorus and sulfur compounds undergo pyramidal inversion, a fundamental and well-recognized stereochemical phenomenon that is widely exploited. However, the stereochemistry of oxonium ions-compounds bearing three substituents on a positively charged oxygen atom-is poorly developed and there are few applications of oxonium ions in synthesis beyond their existence as reactive intermediates.

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The (/)-ocellenynes are C dibrominated natural products whose structures have been subject to several reassignments on the basis of extensive NMR analysis, biosynthetic postulates, and DFT calculations. Herein, we report the synthesis of both ()- and ()-ocellenyne, which, in combination with single crystal X-ray diffraction studies, allows their absolute configuration to be established and defines the configuration of the -12,13-dibromide as being (, ) in keeping with their proposed biogenesis from the (6, 7)-laurediols.

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Background: Non-invasive human biospecimens, including stool, urine, and hair, are important in understanding the relationship between diet and changes in human physiologic processes that affect chronic disease outcomes. However, biospecimen collection can be difficult when collecting samples for research studies that occur away from a centralized location. We describe the protocol and feasibility in collecting stool, urine, and hair biospecimens from parents and their children at a remote location as a part of a summer community garden-based intervention.

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Laurefurenynes C-F are four natural products isolated from species whose structures were originally determined on the basis of extensive nuclear magnetic resonance experiments. On the basis of a proposed biogenesis, involving a tricyclic oxonium ion as a key intermediate, we have reassigned the structures of these four natural products and synthesized the four reassigned structures using a biomimetic approach demonstrating that they are the actual structures of the natural products. In addition, we have developed a synthesis of the enantiomers of the natural products laurencin and deacetyllaurencin from the enantiomer of ()-laurefucin using an unusual retrobiomimetic strategy.

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Reactive intermediates frequently play significant roles in the biosynthesis of numerous classes of natural products although the direct observation of these biosynthetically relevant species is rare. We present here direct evidence for the existence of complex, thermally unstable, tricyclic oxonium ions that have been postulated as key reactive intermediates in the biosynthesis of numerous halogenated natural products from species. Evidence for their existence comes from full characterization of these oxonium ions by low-temperature NMR spectroscopy supported by density functional theory (DFT) calculations, coupled with the direct generation of 10 natural products on exposure of the oxonium ions to various nucleophiles.

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Though they are rare in nature, anthropogenic 1,3,5-triazines have been used in herbicides as chemically stable scaffolds. Here, we show that small 1,3,5-triazines selectively target ascorbate peroxidases (APXs) in Arabidopsis (), tomato (), rice (), maize (), liverwort (), and other plant species. The alkyne-tagged 2-chloro-4-methyl-1,3,5-triazine probe KSC-3 selectively binds APX enzymes, both in crude extracts and in living cells.

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Despite numerous advances in spectroscopic methods through the latter part of the 20th century, the unequivocal structure determination of natural products can remain challenging, and inevitably, incorrect structures appear in the literature. Computational methods that allow the accurate prediction of NMR chemical shifts have emerged as a powerful addition to the toolbox of methods available for the structure determination of small organic molecules. Herein, we report the structure determination of a small, stereochemically rich natural product from Laurencia majuscula using the powerful combination of computational methods and total synthesis, along with the structure confirmation of notoryne, using the same approach.

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The inthomycins are a family of structurally and biologically rich natural products isolated from Streptomyces species. Herein the implementation of a modular synthetic route is reported that has enabled the enantioselective synthesis of all three inthomycins. Key steps include Suzuki and Sonogashira cross-couplings and an enantioselective Kiyooka aldol reaction.

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Salinosporamide A is a β-lactone proteasome inhibitor currently in clinical trials for the treatment of multiple-myeloma. Herein we report a short synthesis of this small, highly functionalized, biologically important natural product that uses an oxidative radical cyclization as a key step and allows for the preparation of gram quantities of advanced synthetic intermediates.

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AimThis service aimed to improve patient access to treatment for urinary tract infections (UTI), impetigo and exacerbation of chronic obstructive pulmonary disease (COPD) and relieve pressure on general practice and out of hours services. BACKGROUND: In 2016, a service (Pharmacy First) was introduced in Forth Valley for the management of UTI, impetigo and exacerbation of COPD using patient group directions in community pharmacies. Trained pharmacists supplied a limited range of prescription medicines.

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Purpose: To explore the perceived and potential roles of pharmacists in the care of young people aged 10-24 years with chronic illness, through the exemplar of juvenile arthritis, from the perspectives of UK community and hospital pharmacists, health service commissioners, rheumatology health professionals, and lay advocates.

Methods: A sequential mixed methods study design comprises the following: focus groups with community and hospital pharmacists; telephone interviews with pharmacy and rheumatology stakeholders and commissioners; and multidisciplinary group discussions to prioritize roles generated by the first two qualitative phases.

Results: The high priority roles for pharmacists, identified by pharmacists and rheumatology staff, were developing generic health care skills among young people; transferring information effectively across care interfaces; building trusting relationships with young people; helping young people to find credible online health information; and the need to develop specialist expertise.

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A short synthesis of the biologically active sesquiterpene natural product (+)-aphanamol I in both racemic and enantiopure forms is reported. Key steps include: a catalytic enantioselective conjugate addition, an oxidative radical cyclization, and a ring-expanding Claisen rearrangement.

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We have recently developed methodology based on oxidative radical reactions for the synthesis of [3.3.0]-bicyclic lactones containing both cyclopentanes and γ-lactams along with application of this methodology to the synthesis of natural products and complex molecular architectures.

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Background: A number of cohort studies and longitudinal household panel studies in Great Britain have asked for consent to link survey data to administrative health data. We explore commonalities and differences in the process of collecting consent, achieved consent rates and biases in consent with respect to socio-demographic, socio-economic and health characteristics. We hypothesise that British cohort studies which are rooted within the health sciences achieve higher consent rates than the UK household longitudinal studies which are rooted within the social sciences.

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A collection of novel, pharmaceutically relevant cubane-containing molecules has been prepared from the commercially available cubane-1,4-dimethylester. A range of synthetic methods have been applied to prepare these cubane building blocks with one or two functional handles to allow easy incorporation into existing medicinal chemistry programs.

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A mild, diastereoselective synthesis of fused lactone-pyrrolidinones using an oxidative radical cyclization is reported. The methodology is demonstrated in a formal synthesis of (-)-salinosporamide A.

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The originally assigned stereostructures of laurefurenynes A and B have been reassigned on the basis of DFT calculations of NMR chemical shifts, synthesis of model compounds and total synthesis of laurefurenyne B, demonstrating the power of this combined approach for stereostructure elucidation/confirmation.

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Elatenyne is a small dibrominated natural product first isolated from Laurencia elata. The structure of elatenyne was originally assigned as a pyrano[3,2-b]pyran on the basis of NMR methods. Total synthesis of the originally proposed pyrano[3,2-b]pyran structure of elatenyne led to the gross structure of the natural product being reassigned as a 2,2'-bifuranyl.

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Manganese(III) acetate mediated oxidative radical cyclizations have been used to synthesize a range of densely functionalized and sterically congested cyclopentane-lactones. A number of the resulting lactones contain vicinal all-carbon quaternary stereocenters adjacent to a tertiary benzylic stereocenter and are formed with high levels of stereocontrol.

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The cyclisation of alkynyl amido- and amino-malonates in the presence of manganese(III) acetate gives exo-alkylidene pyrrolidinones and pyrrolidines with a preference for the (Z)-alkene product isomer.

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