ORCID Profile
0000-0001-7288-3939
Current Organisation
The University of Auckland
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Publisher: Georg Thieme Verlag KG
Date: 07-12-2010
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0MD00301H
Abstract: Mycobacterium tuberculosis isocitrate lyases (ICLs) form a covalent adduct with itaconate through their catalytic cysteine residue. These results reveal atomic details of itaconate inhibition and provide insights into the catalytic mechanism of ICLs.
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/CH12393
Abstract: A series of pyranonaphthoquinone derivatives possessing structural features present in both natural products annulin B and exiguamine A have been shown to exhibit low micromolar inhibition of indoleamine 2,3-dioxygenase-1 (IDO-1). These inhibitors retain activity against the enzyme in a cellular context with an approximate one-log loss of dose potency against IDO-1 in cells. One particular analogue, triazole 8 shows good inhibition of IDO-1 along with little loss of cell viability at low drug concentrations. These results have extended the naphthoquinone series of novel IDO-1 inhibitors based on lead compounds from nature.
Publisher: Elsevier BV
Date: 09-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B708811F
Abstract: A review of the isolation, biological activity and synthesis of pyranonaphthoquinones and closely related compounds is provided.
Publisher: Springer Science and Business Media LLC
Date: 29-07-2016
DOI: 10.1007/S00216-016-9749-8
Abstract: Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen, capable of surviving in a broad range of natural environments and quickly acquiring resistance. It is associated with hospital-acquired infections, particularly in patients with compromised immunity, and is the primary cause of morbidity and mortality in cystic fibrosis (CF) patients. P. aeruginosa is also of nosocomial importance on dairy farms and veterinary hospitals, where it is a key morbidity factor in bovine mastitis. P. aeruginosa uses a cell-cell communication system consisting of signalling molecules to coordinate bacterial secondary metabolites, biofilm formation, and virulence. Simple and sensitive methods for the detection of biomolecules as indicators of P. aeruginosa infection would be of great clinical importance. Here, we report the synthesis of the P. aeruginosa natural product, barakacin, which was recently isolated from the bovine ruminal strain ZIO. A simple and sensitive electrochemical method was used for barakacin detection using a boron-doped diamond (BDD) and glassy carbon (GC) electrodes, based on cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The influence of electrolyte pH on the peak potential and peak currents was also investigated. At pH 2.0, the peak current was linearly dependent on barakacin concentration (in the range used, 1-10 μM), with correlation coefficients greater than 0.98 on both electrodes. The detection limit (S/N = 3) on the BDD electrode was 100-fold lower than that obtained on the GC electrode. The optimized method using the BDD electrode was extended to bovine (cow feces) and human (sputum of a CF patient) s les. Spiked barakacin was easily detected in these matrices at a limit of 0.5 and 0.05 μM, respectively. Graphical abstract Electrochemical detection of barakacin.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5GC02837J
Abstract: A suite of structurally erse N-heterocycles have been prepared from pyrrole and dimethyl itaconate, two compounds attainable from biomass.
Publisher: American Chemical Society (ACS)
Date: 27-09-2010
DOI: 10.1021/JO1016585
Abstract: A microwave-assisted chemoenzymatic resolution has been used to install the C3 stereocenter of the reported structure of the fungal metabolite herbaric acid in high enantiomeric excess. The synthesis and stereochemical assignment was accomplished using a completely regioselective anti-Markovnikov addition of water to vinylphthalide 3, achieved using a heteroatom-directed Wacker oxidation that proceeds with retention of stereochemistry. These results establish that so-called "reverse" Wacker oxidations are a viable alternative to hydroboration/oxidation procedures.
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B911514P
Publisher: Elsevier BV
Date: 11-2007
Publisher: Elsevier BV
Date: 2007
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0MD00241K
Publisher: Elsevier BV
Date: 04-2008
Publisher: Springer Science and Business Media LLC
Date: 11-10-2019
DOI: 10.1038/S41467-019-12614-7
Abstract: Isocitrate lyase is important for lipid utilisation by Mycobacterium tuberculosis but its ICL2 isoform is poorly understood. Here we report that binding of the lipid metabolites acetyl-CoA or propionyl-CoA to ICL2 induces a striking structural rearrangement, substantially increasing isocitrate lyase and methylisocitrate lyase activities. Thus, ICL2 plays a pivotal role regulating carbon flux between the tricarboxylic acid (TCA) cycle, glyoxylate shunt and methylcitrate cycle at high lipid concentrations, a mechanism essential for bacterial growth and virulence.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7MD00456G
Abstract: The enzymes isocitrate lyase (ICL) isoforms 1 and 2 are essential for Mycobacterium tuberculosis survival within macrophages during latent tuberculosis (TB). Herein we report the development of a combined NMR spectroscopy and thermal shift assay for the screening and evaluation of ICL inhibitors.
Publisher: Elsevier BV
Date: 08-2012
DOI: 10.1016/J.BMCL.2012.06.015
Abstract: With over a 100 different serotypes, the human rhinovirus (HRV) is the major aetiological agent for the common cold, for which only symptomatic treatment is available. HRV maturation and replication is entirely dependent on the activity of a virally encoded 3C protease that represents an attractive target for the development of therapeutics to treat the common cold. Although a variety of small molecules and peptidomimetics have been found to inhibit HRV 3C protease, no universally compatible assay exists to reliably quantify the activity of the enzyme in vitro. Herein we report the development of a universal and robust solid phase peptide assay that utilizes the full HRV-14 3C protease recognition sequence and the release of 5(6)-carboxyfluorescein to sensitively quantify protease activity. This novel assay overcomes several limitations of existing assays allowing for the simple and efficient analysis of HRV-14 3C protease activity facilitating both high-throughput screening and the accurate kinetic study of HRV-14 3C protease inhibitors.
Publisher: Georg Thieme Verlag KG
Date: 04-04-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B916041H
Abstract: Although known for over a quarter of a century, the oxidative radical cyclisation route to spiroketals has found limited use in natural product synthesis in comparison to classical approaches. Its successful application in this field of research forms the subject of this perspective.
Publisher: Elsevier BV
Date: 07-2007
Publisher: American Chemical Society (ACS)
Date: 23-07-2014
DOI: 10.1021/JO501344C
Abstract: A full account of our efforts toward an asymmetric synthesis of crisamicin A are presented. The key steps include a Hauser-Kraus annulation of a cyanophthalide with a chiral enone-lactone, a stereoselective cyclization-reduction to install the pyran unit, and a Suzuki homocoupling to forge the key biaryl bond. This work has culminated in the asymmetric synthesis of a dimer bearing the complete carbon skeleton of the dimeric pyranonaphthoquinone natural product crisamicin A.
Publisher: Georg Thieme Verlag KG
Date: 13-05-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3OB41951G
Abstract: The Human Rhinovirus (HRV) is the major aetiological agent for the common cold, for which only symptomatic treatment is available. HRV maturation and replication is entirely dependent on the activity of a virally encoded 3C protease that represents an attractive target for the development of therapeutics to treat the common cold. Herein we report the synthesis and biological evaluation of the 2-methylene analogue of the HRV 3C protease inhibitor (-)-thysanone (1) namely 2-carbathysanone (2), in an attempt to decipher the structural features in the natural product that are responsible for the 3C protease activity. 2-Carbathysanone (2) (and related analogues (±)-cis-23, (±)-cis-30, (±)-31) did not inhibit HRV 3C protease, indicating that the lactol functionality present in (-)-thysanone (1) is a critical structural feature required for inhibition.
Publisher: American Chemical Society (ACS)
Date: 16-06-2017
DOI: 10.1021/ACS.ORGLETT.7B01371
Abstract: The total synthesis of both enantiomers of pestalospirane B, 2, has been achieved using a bioinspired tandem dimerization-spiroketalization reaction. Electronic circular dichroism (ECD) and X-ray analysis were used to revise the absolute stereochemistry of the natural product pestalospirane B from 3S, 3'S, 12R, 12'R to its enantiomer 3R, 3'R, 12S, 12'S.
Publisher: Elsevier BV
Date: 04-2008
Publisher: Wiley
Date: 07-11-2013
Publisher: International Union of Crystallography (IUCr)
Date: 29-03-2008
Publisher: American Chemical Society (ACS)
Date: 09-10-2012
DOI: 10.1021/OL3025956
Abstract: The total syntheses of the initially reported and revised structures of the neuroprotective agent palmyrolide A are reported. The key macrocyclization step was achieved using a sequential ring closing metathesis/olefin isomerization reaction. The synthetic work described herein serves to confirm the recent structural revision of this unusual natural product.
Publisher: Elsevier BV
Date: 05-2008
Publisher: Georg Thieme Verlag KG
Date: 24-02-2009
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/CH13035
Abstract: Twenty nine novel spiroketal derivatives related to the rubromycins were evaluated for their anti-telomerase activity using the real-time quantitative telomeric repeat lification protocol assay. The parent compound γ-rubromycin exhibited the highest potency against human telomerase activity within the series. Modification of the spiroketal motif by the introduction of heteroatoms and substituents at different positions produced analogues with varying bioactivity. Variation at the isocoumarin subunit of the title compound resulted in weaker activity, indicative of its importance in telomerase inhibition.
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.EJMECH.2014.09.063
Abstract: 9-Deoxy analogues of the HRV 3C protease inhibitor (-)-thysanone display better inhibitory properties than the natural product, inferring the C9-OH hinders binding to the enzyme.
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B905077A
Abstract: Studies towards the biomimetic synthesis of cardinalin 3 are described. Despite the successful enantioselective synthesis of the monomeric pyranonaphthoquinone ventiloquinone L, it subsequently failed to undergo a proposed biomimetic homodimerisation to cardinalin 3 using a range of oxidants. However, treatment of a related naphthopyran with cerium ammonium nitrate (CAN) facilitated a tandem biaryl bond formation-oxidative demethylation sequence furnishing a dimeric pyranonaphthoquinone that had exclusively dimerised at C6. The nature of this unusual sequence is discussed and the product subsequently converted to the C6 regioisomer of cardinalin 3.
Publisher: Elsevier BV
Date: 07-2017
DOI: 10.1016/J.DRUDIS.2017.04.012
Abstract: Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis that can remain dormant for many years before becoming active. One way to control and eliminate TB is the identification and treatment of latent TB, preventing infected in iduals from developing active TB and thus eliminating the subsequent spread of the disease. Isocitrate lyase (ICL) is involved in the mycobacterial glyoxylate and methylisocitrate cycles. ICL is important for the growth and survival of M. tuberculosis during latent infection. ICL is not present in humans and is therefore a potential therapeutic target for the development of anti-TB agents. Here, we explore the evidence linking ICL to persistent survival of M. tuberculosis. The structure, mechanism and inhibition of the enzyme is also discussed.
Publisher: Georg Thieme Verlag KG
Date: 09-2007
Publisher: Georg Thieme Verlag KG
Date: 02-07-2008
Publisher: Georg Thieme Verlag KG
Date: 08-06-2009
Publisher: Elsevier BV
Date: 10-2009
DOI: 10.1016/J.BMC.2009.08.064
Abstract: A series of pyranonaphthoquinone derivatives related to the known topoisomerase II inhibitor eleutherin 1 have been shown to act as specific topoisomerase II catalytic inhibitors, with several analogues displaying greater potency than the natural product itself. Amongst the compounds tested were the natural products ventiloquinone L 4 and thysanone 8 with a erse range of topoisomerase II inhibition properties being observed. Interestingly, the natural products are generally weaker inhibitors than their synthetic counterparts, emphasising that subtle changes in the basic molecular structure of a natural product led to significant changes in the inhibition profile. It has also been demonstrated for the first time that analogues related to nanaomycin A and cardinalin-type dimeric pyranonaphthoquinones exhibit potent topoisomerase II inhibitory properties. With respect to structural features, it appears that the nature of the substituents at C1 on the pyran ring and oxygenated substituents on the aryl ring are critical for anti-topoII activity. Importantly, the topoisomerase II inhibition strength does not correlate well with the measured cytotoxicity against yeast, indicating that other molecular features in the pyranonaphthoquinone family must be considered for the design and use of this structural class as highly specific topoisomerase II inhibitors.
Publisher: Georg Thieme Verlag KG
Date: 04-2008
Publisher: Georg Thieme Verlag KG
Date: 04-01-2010
Publisher: American Chemical Society (ACS)
Date: 27-11-2012
DOI: 10.1021/OL302536J
Abstract: A synthetic approach to the tetracyclic core of berkelic acid is reported using gold(I)-catalyzed intramolecular hydroarylation and oxidative radical cyclizations to effect the key ring-forming steps. The carboxylic acid was introduced via a late-stage palladium-catalyzed carbonylation to afford the core tetracycle with the correct relative stereochemistry for the natural product.
Publisher: Wiley
Date: 07-05-2018
Publisher: American Chemical Society (ACS)
Date: 16-08-2019
Abstract: The integrastatins, epicoccolide A and epicoccongirone A, are natural products containing a unique [6.6.6.6]-tetracyclic core framework that exhibit a broad spectrum of biological activities. A synthesis of the common core of epicoccolide A and epicocconigrone A has been achieved using an umpolung alkylation-lactonization to assemble an isochromanone from which the bridged 1,3-dioxane was readily assembled. A different strategy was required to access the core on the integrastatins an initial aryllithium addition to an aldehyde, followed by oxidation and treatment of the masked dihydroxyketone with acid gave the desired core structure.
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B813605J
Abstract: The enantioselective synthesis of a dimeric pyranonaphthoquinone closely related to the cardinalins is described. Whilst attempts to effect a double Hauser-Kraus annulation of enone 5 were unsuccessful using both bis-phthalide 4 and bis-sulfone 21, a single annulation of cyanophthalide 28 with enone 5 furnished functionalised naphthalene 31. Suzuki-Miyaura homocoupling of the aryl triflate 29 derived from 31 effected a late-stage construction of the biaryl bond and facilitated access to the biaryl 3. Double stereoselective lactol reduction installed the 1,3-cis stereochemistry of the pyran rings and a final double oxidative demethylation step furnished model dimer 1, completing the enantioselective synthesis of a dimeric pyranonaphthoquinone bearing the core structure of cardinalin 3.
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1OB05595J
Abstract: The enantioselective syntheses of deoxydihydrokalafungin (5), cis-deoxydihydrokalafungin (6) and deoxykalafungin (7) are reported. The strategy was based on 4 key reactions: (1) CBS reduction of prochiral ketone 10 to introduce chirality at C-1, (2) radical allylation of quinone 9a, (3) cross-metathesis of dimethoxynaphthalene 13 with methyl acrylate, and (4) intramolecular oxa-Michael addition of alcohol 8 to form the core naphthopyran ring system. This novel approach delivers naphthopyrans possessing the natural trans-stereochemistry observed in the pyranonaphthoquinone family of antibiotics.
Publisher: Georg Thieme Verlag KG
Date: 28-11-2011
Publisher: Elsevier BV
Date: 06-2010
Publisher: Georg Thieme Verlag KG
Date: 10-01-2014
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Jonathan Sperry.