ORCID Profile
0000-0001-6313-3298
Current Organisation
University of Tasmania
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Plant Cell and Molecular Biology | Plant Biology | Plant Developmental and Reproductive Biology | Plant Physiology | Medicinal and Biomolecular Chemistry | Biochemistry and Cell Biology not elsewhere classified | Biologically Active Molecules
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Chemical Sciences | Horticultural Crops not elsewhere classified | Plant Production and Plant Primary Products not elsewhere classified | Expanding Knowledge in the Biological Sciences | Grain Legumes |
Related Links
Publications
Isolation and Characterization of 1 β-Acetoxypolygodial fromTasmannia lanceolata
Publisher: Wiley
Date: 09-09-2014
Nuances in Fundamental Suzuki-Miyaura Cross-Couplings Employing [Pd(PPh3 )4 ]: Poor Reactivity of Aryl Iodides at Lower Temperatures
Publisher: American Chemical Society (ACS)
Date: 23-05-2018
Discovery of Periodinane Oxy-Assisted (POA) Oxidation Mechanism in the IBX-Controlled Oxidative Dearomatization of Pyrroles Mediated by Acetic Acid
Publisher: American Chemical Society (ACS)
Date: 26-09-2022
Abstract: The 2-iodoxybenzoic acid (IBX)-controlled oxidative dearomatization of pyrroles occurs very slowly (or not all) in many organic solvents, including DMSO in which IBX is soluble. Interestingly, although IBX is only partially soluble in acetic acid, this solvent mediates the pyrrole oxidative dearomatization. With the aid of density functional theory (DFT) calculations, we have discovered a new mode of reactivity, termed the periodinane oxy-assisted (POA) oxidation mechanism, which explains this observation.
(RS)-2-(3,4-Methylenedioxyphenyl)-5-phenyl-3,6-dihydro-2H-pyran
Publisher: International Union of Crystallography (IUCr)
Date: 26-01-2007
Novel Short-Chain Quinones to Treat Vision Loss in a Rat Model of Diabetic Retinopathy
Publisher: MDPI AG
Date: 20-01-2021
DOI: 10.3390/IJMS22031016
Abstract: Diabetic retinopathy (DR), one of the leading causes of blindness, is mainly diagnosed based on the vascular pathology of the disease. Current treatment options largely focus on this aspect with mostly insufficient therapeutic long-term efficacy. Mounting evidence implicates mitochondrial dysfunction and oxidative stress in the central etiology of DR. Consequently, drug candidates that aim at normalizing mitochondrial function could be an attractive therapeutic approach. This study compared the mitoprotective compounds, idebenone and elamipretide, side-by-side against two novel short-chain quinones (SCQs) in a rat model of DR. The model effectively mimicked type 2 diabetes over 21 weeks. During this period, visual acuity was monitored by measuring optokinetic response (OKR). Vision loss occurred 5–8 weeks after the onset of hyperglycemia. After 10 weeks of hyperglycemia, visual function was reduced by 65%. From this point, the right eyes of the animals were topically treated once daily with the test compounds. The left, untreated eye served as an internal control. Only three weeks of topical treatment significantly restored vision from 35% to 58–80%, while visual acuity of the non-treated eyes continued to deteriorate. Interestingly, the two novel SCQs restored visual acuity better than idebenone or elamipretide. This was also reflected by protection of retinal pathology against oxidative damage, retinal ganglion cell loss, reactive gliosis, vascular leakage, and retinal thinning. Overall, mitoprotective and, in particular, SCQ-based compounds have the potential to be developed into effective and fast-acting drug candidates against DR.
A comparison of some pyrolysis reactions of benzotriazoles, benzisoxazolones and benzisothiazolones
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/B004825I
Photolysis of phenyldisic acids: Evidence for unique product formation from discrete tautomers
Publisher: Royal Society of Chemistry (RSC)
Date: 1994
DOI: 10.1039/C39940001805
Seven-membered rings
Publisher: Elsevier
Date: 2014
Strategies for the synthesis of Stemona alkaloids: an update
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2NP00058J
Abstract: The Stemona alkaloids represent a large and structurally- erse family of natural products. A selection of case studies are presented to showcase the key strategies and progress in the synthesis of these natural products since 2009.
Palladium-catalysed cross-coupling and related reactions involving pyrroles
Publisher: Wiley
Date: 26-06-2006
Abstract: The Pd 0 ‐catalysed cross‐coupling of intact pyrroles with various reaction partners is reviewed. Coverage includes the Buchwald–Hartwig, carbonylation, Heck, Kumada, Negishi, Sonogashira, Stille, Suzuki–Miyaura, Tsuji–Trost, and (Pd 0 ‐catalysed) Ullmann reactions. Some emphasis is given to the application of such processes in the synthesis of pyrrole‐containing natural products. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
How a Bismuth(III) Catalyst Achieves Greatest Activation of Organic Lewis Bases in a Catalytic Reaction: Insights from DFT Calculations
Publisher: Wiley
Date: 25-11-2021
Arbutin Derivatives Isolated from Ancient Proteaceae: Potential Phytochemical Markers Present in Bellendena, Cenarrhenes, and Persoonia Genera
Publisher: American Chemical Society (ACS)
Date: 05-2018
DOI: 10.1021/ACS.JNATPROD.7B01038
Abstract: Extensive phytochemical studies of the paleoendemic Tasmanian Proteaceae species Bellendena montana, Cenarrhenes nitida, and Persoonia gunnii were conducted employing pressurized hot water extraction. As part of these studies, six novel glycosides were isolated, including rare ex les of glycoside-containing natural products featuring tiglic acid esters. These polar molecules may represent potential phytochemical markers in ancient Proteaceae.
Structural Revision of Parvistemoamide: Informing Biosynthetic Proposals of Stemona Alkaloids
Publisher: American Chemical Society (ACS)
Date: 28-07-2022
DOI: 10.1021/ACS.ORGLETT.2C02254
Abstract: The natural product parvistemoamide was isolated in 1991 and has ostensibly eluded synthesis. Its distinctive assigned structure represents the first and only
Exploring Cyclization Strategies to Access Stemona Alkaloids: Subtle Effects Influencing Reactivity in Intramolecular Michael Additions
Publisher: American Chemical Society (ACS)
Date: 22-10-2021
DOI: 10.1021/ACS.ORGLETT.1C03205
Abstract: This report investigates the fundamental basis for rather surprising patterns of reactivity in Brønsted acid-mediated cyclizations of pyrrole substrates bearing pendant Michael acceptors that were identified during syntheses of
Seven-membered rings
Publisher: Elsevier
Date: 2013
Synthesis of Pyrrolidine- and γ-Lactam-Containing Natural Products and Related Compounds from Pyrrole Scaffolds
Publisher: Wiley
Date: 03-12-2022
Abstract: Polycyclic alkaloid natural products featuring pyrrolidine and pyrrolidinone motifs remain enduring targets of total synthesis endeavors. Pyrrole and its derivatives have been exploited to access many such frameworks, including alkaloids belonging to the Aspidosperma , Stemona , and batzelladine families. In this article, a selection of exemplars that highlight the utility of pyrrole‐based approaches to facilitate total syntheses of pyrrolidine‐ and pyrrolidinone‐containing alkaloids and related molecules are showcased.
Unified total syntheses of (±)-sessilifoliamides B, C, and D
Publisher: American Chemical Society (ACS)
Date: 13-04-2021
Levoglucosan and levoglucosenone as bio-based platforms for polymer synthesis
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3PY01019H
The Chemistry of 5-Oxodihydroisoxazoles. XI. The Photolysis of 3-Hydroxy-4-phenylisoxazol-5(2H)-ones (Phenyldisic Acids)
Publisher: CSIRO Publishing
Date: 1995
DOI: 10.1071/CH9950217
Abstract: 3-Hydroxy-2-methyl-4-phenylisoxazol-5(2H)-one, 3-hydroxy-2,4-diphenylisoxazol-5(2H)-one and phenyldisic acid have been photolysed at 254 nm in hydroxylic solvents. By comparison of the respective products with those obtained from 3-methoxy-4-phenylisoxazol- 5(2H)-one, 5-methoxy-4-phenylisoxazol-3(2H)-one and 5(3)-hydroxy-2,2-dimethyl-3(5)-oxo-4-phenyldihydroisoxazolium hydroxide, it is apparent that the disic acids photolyse independently from the 3-hydroxy 5-one, the 5-hydroxy 3-one and the zwitterion tautomers. Novel photochemical pathways for these processes are suggested.
Reassessing the role of N-hydroxytryptamine in auxin Biosynthesis
Publisher: Oxford University Press (OUP)
Date: 25-10-2010
Abstract: The tryptamine pathway is one of five proposed pathways for the biosynthesis of indole-3-acetic acid (IAA), the primary auxin in plants. The enzymes AtYUC1 (Arabidopsis thaliana), FZY (Solanum lycopersicum), and ZmYUC (Zea mays) are reported to catalyze the conversion of tryptamine to N-hydroxytryptamine, putatively a rate-limiting step of the tryptamine pathway for IAA biosynthesis. This conclusion was based on in vitro assays followed by mass spectrometry or HPLC analyses. However, there are major inconsistencies between the mass spectra reported for the reaction products. Here, we present mass spectral data for authentic N-hydroxytryptamine, 5-hydroxytryptamine (serotonin), and tryptamine to demonstrate that at least some of the published mass spectral data for the YUC in vitro product are not consistent with N-hydroxytryptamine. We also show that tryptamine is not metabolized to IAA in pea (Pisum sativum) seeds, even though a PsYUC-like gene is strongly expressed in these organs. Combining these findings, we propose that at present there is insufficient evidence to consider N-hydroxytryptamine an intermediate for IAA biosynthesis.
Seven-membered rings
Publisher: Elsevier
Date: 2011
The Chemistry of 5-Oxodihydroisoxazoles. XI. The Photolysis of 3-Hydroxy-4-phenylisoxazol-5(2H)-ones (Phenyldisic Acids)
Publisher: CSIRO Publishing
Date: 1995
DOI: 10.1071/CH9950217
Abstract: 3-Hydroxy-2-methyl-4-phenylisoxazol-5(2H)-one, 3-hydroxy-2,4-diphenylisoxazol-5(2H)-one and phenyldisic acid have been photolysed at 254 nm in hydroxylic solvents. By comparison of the respective products with those obtained from 3-methoxy-4-phenylisoxazol- 5(2H)-one, 5-methoxy-4-phenylisoxazol-3(2H)-one and 5(3)-hydroxy-2,2-dimethyl-3(5)-oxo-4-phenyldihydroisoxazolium hydroxide, it is apparent that the disic acids photolyse independently from the 3-hydroxy 5-one, the 5-hydroxy 3-one and the zwitterion tautomers. Novel photochemical pathways for these processes are suggested.
Practical isolation of polygodial from Tasmannia lanceolata: a viable scaffold for synthesis
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5OB01573A
Abstract: Polygodial, was efficiently extracted and isolated in gram-scale quantities (3.3% w/w) from Tasmannia lanceolata (Tasmanian native pepper) using a pressurised hot water extraction (PHWE) technique that utilises an unmodified household espresso machine.
Nucleophilic acyl substitution of acyl diimides
Publisher: American Chemical Society (ACS)
Date: 16-06-2009
DOI: 10.1021/JO900923M
Abstract: The nucleophilic acyl substitution of the acyl diimide intermediate formed by the oxidation of isoniazid was found to involve two methanol molecules in a six-membered cyclic transition state. Calculations were performed in the gas phase at the B3LYP/6-311+G(d,p)//B3LYP/6-31G(d) level of theory and solvation effects were included both explicitly and implicitly by using CPCM. The effect of electron withdrawing and donating groups on the aryl ring was also explored. The results obtained are in good agreement with experimental observations for the oxidation of isoniazid.
Binuclear manganese complexes as catalysts in the selective and efficient oxidation of sulfides to sulfones
Publisher: Elsevier BV
Date: 09-1998
Towards high capacity latex-coated porous polymer monoliths as ion-exchange stationary phases
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B511398A
Abstract: The preparation of high capacity agglomerated monolithic ion-exchangers for capillary ion chromatography is described. Post-modification of reactive monoliths was investigated as an alternative to co-polymerisation of a suitable functional monomer with an overarching goal of increasing ion-exchange capacity. Direct sulfonation of poly styrene-co- inyl benzene monoliths using concentrated sulfuric acid or chlorosulfonic acid was unsuccessful even for monoliths containing as low as 8% crosslinker. In contrast, chemical transformation of reactive monoliths containing glycidyl methacrylate was used to increase the ion-exchange capacity by up to more than thirty-fold with ion exchange capacities of 14-29 microequiv g(-1) achieved. Three different reactions were considered, including reaction with 4-hydroxybenenesulfonic acid under basic conditions reaction with thiobenzoic acid followed by transformation to a reactive thiol and the subsequent oxidation to the sulfonic acid and direct sulfonation with sodium sulfite. Of these, the reaction with sodium sulfite resulted in the most significant increase in the capacity and the best separation performance. In the isocratic mode separation efficiencies of over 13,500 plates m(-1) were observed (for iodate). The separation of seven inorganic anions was also demonstrated using a hydroxide gradient.
Knorr-Rabe partial reduction of pyrroles: Application to the synthesis of indolizidine alkaloids
Publisher: Beilstein Institut
Date: 15-01-2008
Palladium-mediated organic synthesis using porous polymer monolith formed in situ as a continuous catalyst support structure for application in microfluidic devices
Publisher: Elsevier BV
Date: 02-2009
Chapter 7: Seven-membered rings
Publisher: Elsevier
Date: 2009
Oxidation of Phenylhydrazones with Benzeneseleninic Anhydride: A New Mechanistically Interesting Observation
Publisher: Springer Science and Business Media LLC
Date: 13-01-1998
Evidence for a higher oxidation state of manganese in the reaction of dinuclear manganese complexes with oxidants. Comparison with iron based gif chemistry
Publisher: Elsevier BV
Date: 04-1998
Polygodial and Ophiobolin A Analogues for Covalent Crosslinking of Anticancer Targets
Publisher: MDPI AG
Date: 19-10-2021
Abstract: In a search of small molecules active against apoptosis-resistant cancer cells, including glioma, melanoma, and non-small cell lung cancer, we previously prepared α,β- and γ,δ-unsaturated ester analogues of polygodial and ophiobolin A, compounds capable of pyrrolylation of primary amines and demonstrating double-digit micromolar antiproliferative potencies in cancer cells. In the current work, we synthesized dimeric and trimeric variants of such compounds in an effort to discover compounds that could crosslink biological primary amine containing targets. We showed that such compounds retain the pyrrolylation ability and possess enhanced single-digit micromolar potencies toward apoptosis-resistant cancer cells. Target identification studies of these interesting compounds are underway.
Synthesis and phytotoxicity of structural analogues of thaxtomin natural products
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/CH10006
Abstract: Structural analogues of the phytotoxic thaxtomin natural products have been synthesized by building upon a piperazinedione core and from l-phenylalanine. The compounds were evaluated for their phytotoxic activity against Arabidopsis thaliana seedlings and some of the key features for activity have been identified.
Capstone Laboratory Experiment Investigating Key Features of Palladium-Catalyzed Suzuki-Miyaura Cross-Coupling Reactions
Publisher: American Chemical Society (ACS)
Date: 14-09-2018
Hydrogen/deuterium exchange on aromatic rings during atmospheric pressure chemical ionization mass spectrometry
Publisher: Wiley
Date: 09-03-2010
DOI: 10.1002/RCM.4488
Abstract: It has been demonstrated that substituted indoles fully labelled with deuterium on the aromatic ring can undergo substantial exchange back to partial and even fully protonated forms during atmospheric pressure chemical ionisation (APCI) liquid chromatography/mass spectrometry (LC/MS). The degree of this exchange was strongly dependent on the absolute quantity of analyte, the APCI desolvation temperature, the nature of the mobile phase, the mobile phase flow rate and the instrument used. Hydrogen/deuterium (H/D) exchange on several other aromatic ring systems during APCI LC/MS was either undetectable (nitrobenzene, aniline) or extremely small (acetanilide) compared to the effect observed for substituted indoles. This observation has major implications for quantitative assays using deuterium-labelled internal standards and for the detection of deuterium-labelled products from isotopically labelled feeding experiments where there is a risk of back exchange to the protonated form during the analysis.
Chapter 7: Seven-Membered Rings
Publisher: Elsevier
Date: 2009
Development and Applications of Water-based Extraction Methods in Natural Products Isolation Chemistry
Publisher: Wiley
Date: 02-07-2020
Asperuloside Enhances Taste Perception and Prevents Weight Gain in High-Fat Fed Mice
Publisher: Frontiers Media SA
Date: 13-04-2021
DOI: 10.3389/FENDO.2021.615446
Abstract: Asperuloside is an iridoid glycoside found in many medicinal plants that has produced promising anti-obesity results in animal models. In previous studies, three months of asperuloside administration reduced food intake, body weight, and adipose masses in rats consuming a high fat diet (HFD). However, the mechanisms by which asperuloside exerts its anti-obesity properties were not clarified. Here, we investigated homeostatic and nutrient-sensing mechanisms regulating food intake in mice consuming HFD. We confirmed the anti-obesity properties of asperuloside and, importantly, we identified some mechanisms that could be responsible for its therapeutic effect. Asperuloside reduced body weight and food intake in mice consuming HFD by 10.5 and 12.8% respectively, with no effect on mice eating a standard chow diet. Fasting glucose and plasma insulin were also significantly reduced. Mechanistically, asperuloside significantly reduced hypothalamic mRNA ghrelin, leptin, and pro-opiomelanocortin in mice consuming HFD. The expression of fat lingual receptors (CD36, FFAR1-4), CB1R and sweet lingual receptors (TAS1R2-3) was increased almost 2-fold by the administration of asperuloside. Our findings suggest that asperuloside might exert its therapeutic effects by altering nutrient-sensing receptors in the oral cavity as well as hypothalamic receptors involved in food intake when mice are exposed to obesogenic diets. This signaling pathway is known to influence the subtle hypothalamic equilibrium between energy homeostasis and reward-induced overeating responses. The present pre-clinical study demonstrated that targeting the gustatory system through asperuloside administration could represent a promising and effective new anti-obesity strategy.
Activity of natural and synthetic polygodial derivatives against Trypanosoma cruzi amastigotes, trypomastigotes and epimastigotes
Publisher: Informa UK Limited
Date: 28-04-2021
Distinct Drimane Chemotypes in Tasmanian Mountain Pepper (Tasmannia lanceolata): Differences in the Profiles of Pungent Leaf Phytochemicals Associated with Altitudinal Cline
Publisher: American Chemical Society (ACS)
Date: 18-12-2020
Abstract: This study assesses whether the distinct altitudinal cline in leaf morphology (decreased leaf width and length with increased altitude) in Tasmanian mountain pepper (
Comparative In Vitro Toxicology of Novel Cytoprotective Short-Chain Naphthoquinones
Publisher: MDPI AG
Date: 07-08-2020
DOI: 10.3390/PH13080184
Abstract: Short-chain quinones (SCQs) have been identified as potential drug candidates against mitochondrial dysfunction, which largely depends on the reversible redox characteristics of the active quinone core. We recently identified 11 naphthoquinone derivatives, 1–11, from a library of SCQs that demonstrated enhanced cytoprotection and improved metabolic stability compared to the clinically used benzoquinone idebenone. Since the toxicity properties of our promising SCQs were unknown, this study developed multiplex methods and generated detailed toxicity profiles from 11 endpoint measurements using the human hepatocarcinoma cell line HepG2. Overall, the toxicity profiles were largely comparable across different assays, with simple standard assays showing increased sensitivity compared to commercial toxicity assays. Within the 11 naphthoquinones tested, the L-phenylalanine derivative 4 consistently demonstrated the lowest toxicity across all assays. The results of this study not only provide useful information about the toxicity features of SCQs but will also enable the progression of the most promising drug candidates towards their clinical use.
Distinctive Arbutin‐Containing Markers: Chemotaxonomic Significance and Insights Into the Evolution of Proteaceae Phytochemistry
Publisher: Wiley
Date: 13-10-2023
Development of a novel fluorescent tag O-2-[aminoethyl]fluorescein for the electrophoretic separation of oligosaccharides
Publisher: Elsevier BV
Date: 03-2010
DOI: 10.1016/J.ACA.2010.01.011
Abstract: This study describes the development of a novel fluorescent tag, O-2-[aminoethyl]fluorescein, for the separation of sugars by capillary electrophoresis with fluorescence detection using an argon ion laser. The tag was synthesised using three consecutive steps namely: esterification, alkylation and hydrolysis, specifically designed to offer a flexible way in which to make an assortment of fluorescent tags from cheap and readily available starting reagents (typically less than $1 per g of fluorescent tag). Via this flexible synthetic pathway, O-2-[aminoethyl]fluorescein was designed and synthesised with a spacer group to lower steric effects between the fluorescein backbone and the reducing end of the carbohydrate which were anticipated to improve the reactivity of the tag. The newly synthesised tag, O-2-[aminoethyl]fluorescein was evaluated against structurally similar commercial fluorescent motifs namely fluorescent 5-aminomethylfluorescein and non-fluorescent 5-aminofluorescein. Kinetic studies indicated that O-2-[aminoethyl]fluorescein showed similar labeling efficiencies as 5-aminomethylfluorescein, but were achieved in only 30 min, supporting the notion of improved reactivity of the spacer group. The sensitivity of O-2-[aminoethyl]fluorescein was evaluated using maltoheptaose with a detection limit of 1 nM obtained, which was slightly higher than that of 0.3 nM obtained with 5-aminomethylfluorescein, and was due to its lower quantum yield (0.24) when conjugated to the sugar. The separation performance of the tag was also benchmarked with the two commercial reagents using a range of corn syrup oligosaccharides, from 4 to 10 glucose units, typically found in rice starch. Separations were performed using an electrolyte containing 100 mM boric acid, tris at pH 8.65 as background electrolyte, 30 kV applied voltage, 50 microm I.D. x 40 cm (30 cm effective length) capillary. The novel tag showed better resolution of small oligosaccharides, G3 and G4, than the other two reagents, but slightly worse resolution for the longer oligosaccharides, most likely due to the monovalent charge state of the O-2-[aminoethyl]fluorescein compared to the alent charge of the other two tags.
UV initiated formation of polymer monoliths in glass and polymer microreactors
Publisher: Elsevier BV
Date: 07-2011
Natural products isolation studies of the paleoendemic plant species Nothofagus gunnii and Nothofagus cunninghamii
Publisher: Elsevier BV
Date: 2022
DOI: 10.1016/J.FITOTE.2021.105088
Abstract: The first natural product isolation studies of Nothofagus gunnii (Hook.f.) Oerst and Nothofagus cunninghamii (Hook.f.) Oerst have been undertaken. A previously unreported stilbene derivative, pinosylvin monoacetate, was isolated from the leaves of N. gunnii, in addition to 14 known compounds including the flavonoids galangin, pinobanksin, catechin and quercetin sesquiterpenoids such as, ilicol and (+)-β-costol acetate 2,4-dihydroxy-6-methoxychalcone and pinosylvin. Four known flavonoid natural products, catechin, quercetin, ayanin, and avicularin were isolated from the leaves of N. cunninghamii. This study reveals that N. gunnii is a rich source of flavonoid, chalcone and stilbene compounds, while primarily hydroxyflavonoid compounds are found in N. cunninghamii. The isolated phytochemicals are consistent with the evolutionary relationships suggested to exist among Nothofagus species.
Annulation of pyrrole: Application to the synthesis of indolizidine alkaloids
Publisher: Elsevier BV
Date: 08-2005
The regioselective synthesis of aryl pyrroles
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B604692D
Abstract: Pyrrole is a unique aromatic molecule as it can readily undergo substitution at all five positions but obtaining the desired regioisomer can prove difficult to control. We now report our results on the regioselective arylation of pyrrole, utilizing selective halogenation and the Suzuki-Miyaura reaction to prepare C4-, C5- and C3-aryl derivatives. We have applied this methodology to the synthesis of lamellarin O dimethyl ether, an intermediate in the synthesis of lukinol A.
Triplet lifetimes, solvent, and intramolecular capture of isoxazolones
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/CH03140
Abstract: The first step in the photochemical decarboxylation of isoxazolones is the formation of the triplet state of the isoxazolone. We present evidence for the first time from flash laser photolysis of the lifetime of such species, and ex les of their capture by solvent and by intramolecular cycloaddition.
Study of a new reaction: Trapping of peroxyl radicals by TEMPO
Publisher: Elsevier BV
Date: 10-1998
Mechanistic investigation of the oxidation of hydrazides: Implications for the activation of the TB drug isoniazid
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2OB26419F
Abstract: Aryl hydrazides are oxidised to acyl radicals through a mechanism involving diimide intermediates that are prone to nucleophilic acyl substitution. This oxidation occurs regardless of the oxidant involved, however there is no evidence that the acyl radical formed undergoes further oxidation to the corresponding acylium ion, even in the presence of strong oxidants. This study may provide insight into the mechanism of isoniazid resistance in Mycobacterium tuberculosis.
Pressurized Hot Water Extraction and Capillary Electrophoresis for Green and Fast Analysis of Useful Metabolites in Plants
Publisher: MDPI AG
Date: 26-06-2019
DOI: 10.3390/MOLECULES24132349
Abstract: The search for useful compounds from plants is an important research area. Traditional screening that involves isolation and identification/quantitation is tedious, time consuming, and generates a significant amount of chemical waste. Here, we present a simple, fast, and green strategy to assess ≥0.1% wt/wt quantities of useful compounds in plants/spices using pressurized hot water extraction using a household espresso machine followed by chemical analysis using capillary electrophoresis. Three demonstrations with polygodial, cinnamaldehyde, coumarin, and shikimic acid as target metabolites are shown. Direct analysis of extracts was by the developed micellar electrokinetic chromatography and capillary zone electrophoresis methods. The approach, which can be implemented in less developed countries, can process many s les within a day, much faster than traditional techniques that would normally take at least a day. Finally, 0.8–1.1% wt/wt levels of shikimic acid were found in Tasmanian-pepperberry and Tasmanian-fuschia leaves via the approach.
Acyl radical addition to pyridine: multiorbital interactions
Publisher: Elsevier BV
Date: 09-2009
Cow dung biomass smoke exposure increases adherence of respiratory pathogen nontypeable Haemophilus infuenzae to human bronchial epithelial cells
Publisher: Springer Science and Business Media LLC
Date: 09-03-2020
The synthesis of oxazoles by thermolysis or photolysis of 2-acylisoxazol-5-ones
Publisher: Elsevier BV
Date: 1996
The selective functionalization of saturated hydrocarbons. Part 42. Further studies in selective phenylselenation
Publisher: Elsevier BV
Date: 02-1998
Methyl 4-chloro-3,5-di-p-tolyl-1H-pyrrole-2-carboxylate dichloromethane hemisolvate
Publisher: International Union of Crystallography (IUCr)
Date: 08-12-2007
The influence of chiral auxiliaries and catalysts on the selectivity of intramolecular conjugate additions of pyrrole to N-tethered Michael acceptors
Publisher: Royal Society of Chemistry (RSC)
Date: 2004
DOI: 10.1039/B312552A
Abstract: A series of pyrroles incorporating N-tethered acrylates and related groups has been prepared and examined for their capacity to undergo intramolecular Michael addition reactions to form, in a diastereo- or enantio-selective fashion, the corresponding 8-substituted tetrahydroindolizidine or homologues thereof.
Macroporous monolith supports for continuous flow capillary microreactors
Publisher: Elsevier BV
Date: 12-2006
A total synthesis of the styryllactone (+)-goniodiol from naphthalene
Publisher: CSIRO Publishing
Date: 2003
DOI: 10.1071/CH02242
Abstract: The cytotoxic natural product (+)-goniodiol (1) has been prepared in twelve steps from the enantiomerically pure cis-dihydrocatechol (2), which is readily obtained by microbial oxidation of naphthalene. Elaboration of compound (2) involves an initial oxidative cleavage to dialdehyde (7) followed by reduction to give diol (12). Conversion of compound (12) into acetal (17) required, inter alia, selective oxidation of the benzylic alcohol moiety followed by a metal-catalyzed decarbonylation of the resulting aldehyde. Allylation of compound (17) with allyltributylstannane in the presence of lithium perchlorate gave a ca. 2.7 : 1 mixture of alcohols (18) and (19), each of which was converted into the corresponding acrylate under standard conditions. Subjection of these ester derivatives to a ring-closing metathesis (RCM) reaction with Grubbs' first-generation catalyst gave the anticipated lactones (22) and (23). Acid-catalyzed removal of the acetonide protecting group within compound (22) then afforded (+)-goniodiol (1), while analogous deprotection of congener (23) afforded 6-epi-(+)-goniodiol (24).
Methods for the synthesis of annulated pyrroles: Via cyclisation strategies
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7OB03144K
Abstract: In this report, we review the methods that have been employed to synthesise annulated pyrroles.
Three or Four Heteroatoms Including at Least One Arsenic or Antimony
Publisher: Elsevier
Date: 2022
Total synthesis of (±)-rhazinal, an alkaloidal spindle toxin from Kopsia teoi
Publisher: Royal Society of Chemistry (RSC)
Date: 19-12-2003
DOI: 10.1039/B209992F
Abstract: The title alkaloid 1 and its B-nor-congener 3, both of which display potent and unusual anti-mitotic properties, have been synthesized in racemic form and characterised by single-crystal X-ray analysis.
Employing pressurized hot water extraction (Phwe) to explore natural products chemistry in the undergraduate laboratory
Publisher: MyJove Corporation
Date: 07-11-2018
DOI: 10.3791/58195
Abstract: A recently developed pressurized hot water extraction (PHWE) method which utilizes an unmodified household espresso machine to facilitate natural products research has also found applications as an effective teaching tool. Specifically, this technique has been used to introduce second- and third-year undergraduates to aspects of natural products chemistry in the laboratory. In this report, two experiments are presented: the PHWE of eugenol and acetyleugenol from cloves and the PHWE of seselin and (+)-epoxysuberosin from the endemic Australian plant species Correa reflexa. By employing PHWE in these experiments, the crude clove extract, enriched in eugenol and acetyleugenol, was obtained in 4-9% w/w from cloves by second-year undergraduates and seselin and (+)-epoxysuberosin were isolated in yields of up to 1.1% w/w and 0.9% w/w from C. reflexa by third-year students. The former exercise was developed as a replacement for the traditional steam distillation experiment providing an introduction to extraction and separation techniques, while the latter activity featured guided-inquiry teaching methods in an effort to simulate natural products bioprospecting. This primarily derives from the rapid nature of this PHWE technique relative to traditional extraction methods that are often incompatible with the time constraints associated with undergraduate laboratory experiments. This rapid and practical PHWE method can be used to efficiently isolate various classes of organic molecules from a range of plant species. The complementary nature of this technique relative to more traditional methods has also been demonstrated previously.
Separation of the primary and secondary kinetic isotope effects at a reactive center using starting material reactivities. Application to the FeCl3-catalyzed oxidation of C-H bonds with tert-butyl hydroperoxide
Publisher: Elsevier BV
Date: 05-1999
Radical scavenging activity and metabolomic profiling study of ylang-ylang essential oils based on high-performance thin-layer chromatography and multivariate statistical analysis
Publisher: Elsevier BV
Date: 08-2021
Acyl radical addition to benzene and related systems - A computational study
Publisher: Elsevier BV
Date: 09-2010
Progress in the Development of Platelet-Activating Factor Receptor (PAFr) Antagonists and Applications in the Treatment of Inflammatory Diseases
Publisher: Wiley
Date: 16-08-2018
Abstract: Platelet-activating factor (PAF) and its receptor (PAFr) have been implicated in a wide range of diseases and disorders that originate from the activation of inflammatory pathways. Although the exact structure of the binding site on the PAFr remains unknown, the PAFr is a well-established therapeutic target, and an array of structurally erse PAFr antagonists have been identified. These include compounds that are structurally similar to the natural PAF ligand, synthetic heterocycles, complex polycyclic natural products, and various metal complexes. This review provides an update on more than 20 years of progress in this area. The development and synthesis of new PAFr antagonists, structure-activity relationship studies, the biological activity of these molecules, and their therapeutic potential are discussed.
Furanosesquiterpenes and Related Natural Products from Myoporum Species: Isolation and Semisynthesis
Publisher: American Chemical Society (ACS)
Date: 06-2023
Analysis of the enol-keto tautomers of indole-3-pyruvic acid
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/CH14343
Abstract: Indole-3-pyruvic acid (IPyA) is an important naturally occurring biosynthetic intermediate whose quantitation by standard analytic techniques can be complicated as it can exist as either the keto or enol tautomer. Here, we present a detailed analysis of the tautomerism of IPyA and provide further evidence that the two tautomers of IPyA may be readily separated by ultra high-performance liquid chromatography and that the relative proportions of each form may be controlled using temperature and pH.
Microfluidic devices for flow-through supported palladium catalysis on porous organic monolith
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/CH08160
Abstract: Flow-through microreactors are described, constructed of fused silica capillaries with an internal diameter of 100 μm and glass microchips with a channel dimension of 150 μm and involving the in situ UV-initiated synthesis of a poly(glycidyl methacrylate-co-ethylene dimethacrylate) porous polymer monolith. The monolith is a continuous material covalently bonded to the capillary or chip walls, with good flow-through properties. Epoxide ring-opening through amine attack by 5-amino-1,10-phenanthroline and coordination to dichloropalladium(ii) allows use of the microreactors for Suzuki–Miyaura catalysis. The long-term stability and reliability of the robust chip microreactor is demonstrated by operation for 96 h, exhibiting undiminished reactivity, and very low leaching of palladium.
Characterization of Wear Mechanisms of Silicon Carbide Materials
Publisher: Trans Tech Publications Ltd
Date: 27-10-2010
A mild, one-pot method for the conversion of carboxylic acids into the corresponding Weinreb amides
Publisher: Informa UK Limited
Date: 2001
Identification, Synthesis and Field Testing of (3Z,6Z,9Z)-3,6,9-Henicosatriene, a Second Bioactive Component of the Sex Pheromone of the Autumn Gum Moth, Mnesampela privata
Publisher: Springer Science and Business Media LLC
Date: 12-2009
DOI: 10.1007/S10886-009-9717-2
Abstract: The sex pheromone of Mnes ela privata, an endemic pest of Eucalyptus plantations in Australia, was previously identified as a single bioactive compound, (3Z,6Z,9Z)-3,6,9-nonadecatriene (C19 triene). Initial field testing of lures containing 1 mg, 5 mg or 10 mg of C19 triene (>98% purity) caught no or very few male M. privata. (3Z,6Z,9Z)-3,6,9-Henicosatriene (C21 triene) was identified as an additional minor pheromone component in abdominal tip extracts of M. privata females from Tasmania. Levels of both compounds extracted from in idual females varied greatly, but the ratio was relatively constant at 33:1 C19:C21 trienes. Electroantennograms (EAG) of synthetic C21 triene with male M. privata gave positive but consistently lower responses than elicited by the C19 triene. Field tests showed that the addition of 1-6% C21 triene to 1 mg C19 triene significantly increased trap catch and the detection of M. privata in plantations. Traps baited with a 16:1 ratio caught significantly more moths than those baited with a ratio approximating that of females.
Seven-Membered Rings
Publisher: Elsevier
Date: 2012
A new and high yielding synthesis of unstable pyrroles via a modified Clauson-Kaas reaction
Publisher: Elsevier BV
Date: 2006
Short-Chain Naphthoquinone Protects Against Both Acute and Spontaneous Chronic Murine Colitis by Alleviating Inflammatory Responses
Publisher: Frontiers Media SA
Date: 23-08-2021
DOI: 10.3389/FPHAR.2021.709973
Abstract: Ulcerative colitis (UC) is characterised by chronic, relapsing, idiopathic, and multifactorial colon inflammation. Recent evidence suggests that mitochondrial dysfunction plays a critical role in the onset and recurrence of this disease. Previous reports highlighted the potential of short-chain quinones (SCQs) for the treatment of mitochondrial dysfunction due to their reversible redox characteristics. We hypothesised that a recently described potent mitoprotective SCQ (UTA77) could ameliorate UC symptoms and pathology. In a dextran sodium sulphate- (DSS-) induced acute colitis model in C57BL/6J mice, UTA77 substantially improved DSS-induced body weight loss, disease activity index (DAI), colon length, and histopathology. UTA77 administration also significantly increased the expression of tight junction (TJ) proteins occludin and zona-occludin 1 (ZO-1), which preserved intestinal barrier integrity. Similar responses were observed in the spontaneous Winnie model of chronic colitis, where UTA77 significantly improved DAI, colon length, and histopathology. Furthermore, UTA77 potently suppressed elevated levels of proinflammatory cytokines and chemokines in colonic explants of both DSS-treated and Winnie mice. These results strongly suggest that UTA77 or its derivatives could be a promising novel therapeutic approach for the treatment of human UC.
A mechanistic study on the oxidation of hydrazides: Application to the tuberculosis drug isoniazid
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B719570B
Abstract: Herein we report radical trapping experiments that support the formation of an acyl radical as the active species from the oxidation of isoniazid these data provide insight into the mechanism of hydrazide oxidation.
Metabolic Stability of New Mito-Protective Short-Chain Naphthoquinones
Publisher: MDPI AG
Date: 12-02-2020
DOI: 10.3390/PH13020029
Abstract: Short-chain quinones (SCQs) have been identified as potential drug candidates against mitochondrial dysfunction, which is largely dependent on their reversible redox characteristics of the active quinone core. We recently synthesized a SCQ library of 148 naphthoquinone derivatives and identified 16 compounds with enhanced cytoprotection compared to the clinically used benzoquinone idebenone. One of the major drawbacks of idebenone is its high metabolic conversion in the liver, which significantly restricts its therapeutic activity. Therefore, this study assessed the metabolic stability of the 16 identified naphthoquinone derivatives 1–16 using hepatocarcinoma cells in combination with an optimized reverse-phase liquid chromatography (RP-LC) method. Most of the derivatives showed significantly better stability than idebenone over 6 hours (p 0.001). By extending the side-chain of SCQs, increased stability for some compounds was observed. Metabolic conversion from the derivative 3 to 5 and reduced idebenone metabolism in the presence of 5 were also observed. These results highlight the therapeutic potential of naphthoquinone-based SCQs and provide essential insights for future drug design, prodrug therapy and polytherapy, respectively.
Amide linked redox-active naphthoquinones for the treatment of mitochondrial dysfunction
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8MD00582F
Abstract: Naphthoquinones have been investigated as potential therapeutic molecules for neurodegenerative disorders, which is largely based on their anti-oxidative potential.
Border between natural product and drug: Comparison of the related benzoquinones idebenone and coenzyme Q10
Publisher: Elsevier BV
Date: 04-2015
Novel polygodial analogs P3 and P27: Efficacious therapeutic agents disrupting mitochondrial function in oral squamous cell carcinoma
Publisher: Spandidos Publications
Date: 05-10-2018
Computational Investigation into the Mechanistic Features of Bromide-Catalyzed Alcohol Oxidation by PhIO in Water
Publisher: American Chemical Society (ACS)
Date: 27-01-2021
Convergent synthesis and preliminary biological evaluation of (±)-B-norrhazinal
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/B001731K
ent-Labdane Diterpenoids from Dodonaea viscosa
Publisher: American Chemical Society (ACS)
Date: 08-12-2016
DOI: 10.1021/ACS.JNATPROD.6B00858
Abstract: Seven new and two known ent-labdane diterpenoids have been isolated from a single plant specimen of Dodonaea viscosa ssp. spatulata, found in Tasmania, Australia. Prior to this study, only seven different labdane diterpenoids had been isolated from D. viscosa. The structures of the natural products were assigned via 1D and 2D NMR spectroscopy and other standard spectroscopic methods. The absolute configuration of three ent-labdane diterpenoids was determined by single-crystal X-ray crystallography of synthetic derivatives. Significantly, the results of this study suggest that the absolute configuration of some known labdane diterpenoids may have been misassigned.
Intraspecific Variation in the Terpene Profiles of Dodonaea viscosa
Publisher: Wiley
Date: 23-03-2023
Abstract: Natural products isolation studies were performed on Dodonaea viscosa plant in iduals s led across seven different populations, which revealed considerable intraspecific variation in the terpene profiles across D. viscosa . In total, 14 ent‐ labdane diterpenoids (seven of which are previously unreported), four ent‐ kauranes (one which is previously unreported), one rare norhopene, and two previously unreported monoterpenoid wax esters were isolated. Exceedingly few terpene wax esters have been reported in Nature and the isolation of these unusual secondary metabolites is particularly notable for this reason. In each case, the proposed structures were elucidated employing various standard one‐ and two‐dimensional NMR ( 1 H, 13 C, NOESY, COSY, HSQC, HMBC) spectroscopic techniques and complemented by IR spectroscopy, mass spectrometry, and polarimetry, where appropriate. Synthetic derivatization and X‐ray crystallographic analysis were also employed to further support or secure structural assignments.
Use of the anti-oxidant butylated hydroxytoluene in situ for the synthesis of readily oxidized compounds: Application to the synthesis of the moth pheromone (Z,Z,Z)-3,6,9-nonadecatriene
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/CH07223
Abstract: The triene (Z,Z,Z)-3,6,9-nonadecatriene was synthesized in three steps from methyl linolenate. The key to the synthesis was the use of the anti-oxidant butylated hydroxytoluene in situ to provide protection of the unstable triene from autoxidation during reaction workup. This simple modification resulted in an increase in the yield from 20 to 85% over three steps.
Methyl 4-p-tolyl-1H-pyrrole-2-carboxylate
Publisher: International Union of Crystallography (IUCr)
Date: 10-01-2007
3-(Oxazolo[4,5-b]pyridin-2-yl)anilides as a novel class of potent inhibitors for the kinetoplastid Trypanosoma brucei, the causative agent for human African trypanosomiasis
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.EJMECH.2013.05.007
Abstract: A whole organism high-throughput screen of approximately 87,000 compounds against Trypanosoma brucei brucei led to the recent discovery of several novel compound classes with low micromolar activity against this organism and without appreciable cytotoxicity to mammalian cells. Herein we report a structure-activity relationship (SAR) investigation around one of these hit classes, the 3-(oxazolo[4,5-b]pyridin-2-yl)anilides. Sharp SAR is revealed, with our most active compound (5) exhibiting an IC₅₀ of 91 nM against the human pathogenic strain T.b. rhodesiense and being more than 700 times less toxic towards the L6 mammalian cell line. Physicochemical properties are attractive for many compounds in this series. For the most potent representatives, we show that solubility and metabolic stability are key parameters to target during future optimisation.
Three or Four Heteroatoms Including at Least One Boron
Publisher: Elsevier
Date: 2022
DFT-Based Comparison between Mechanistic Aspects of Amine and Alcohol Oxidation Mediated by IBX
Publisher: American Chemical Society (ACS)
Date: 26-12-2020
Abstract: Density functional theory was utilized to investigate plausible mechanisms for amine and alcohol oxidation by an iodine(V) hypervalent reagent (IBX). In this contribution, we found that amine and alcohol oxidation both proceed by similar mechanisms. The reactions initiate from ligand exchange to give four coordinate intermediates followed by a redox process giving an iodine(III) species and oxidized substrates. Interestingly, for both the ligand-exchange and the redox steps a hypervalent twist is required for the reaction to proceed via an energetically more accessible route. The ligand-exchange process was found to be mediated by a proton-shuttling agent such as water, a second IBX, or a second substrate. While the ligand-exchange step for both amine and alcohol occurs with almost identical activation energy (particularly when water is considered as the shuttling agent), the redox step for the amine takes place with much lower activation energy than that for the alcohol. Finally, we ascertained that five coordinate amide iodine(V) complexes are unreactive toward redox reactions due to the fact that in such cases two electrons from the coordinated amide are required to occupy a 3c-4e σ* orbital which is too high in energy to be reachable.
Reassessing the role of YUCCAs in auxin biosynthesis
Publisher: Informa UK Limited
Date: 03-2011
Bioactivity Profiles of Cytoprotective Short-Chain Quinones
Publisher: MDPI AG
Date: 04-03-2021
DOI: 10.3390/MOLECULES26051382
Abstract: Short-chain quinones (SCQs) have been investigated as potential therapeutic candidates against mitochondrial dysfunction, which was largely thought to be associated with the reversible redox characteristics of their active quinone core. We recently reported a library of SCQs, some of which showed potent cytoprotective activity against the mitochondrial complex I inhibitor rotenone in the human hepatocarcinoma cell line HepG2. To better characterize the cytoprotection of SCQs at a molecular level, a bioactivity profile for 103 SCQs with different compound chemistries was generated that included metabolism related markers, redox activity, expression of cytoprotective proteins and oxidative damage. Of all the tested endpoints, a positive correlation with cytoprotection by SCQs in the presence of rotenone was only observed for the NAD(P)H:quinone oxidoreductase 1 (NQO1)-dependent reduction of SCQs, which also correlated with an acute rescue of ATP levels. The results of this study suggest an unexpected mode of action for SCQs that appears to involve a modification of NQO1-dependent signaling rather than a protective effect by the reduced quinone itself. This finding presents a new selection strategy to identify and develop the most promising compounds towards their clinical use.
Supported palladium catalysis using a heteroleptic 2-methylthiomethylpyridine-N,S-donor motif for Mizoroki-Heck and Suzuki-Miyaura coupling, including continuous organic monolith in capillary microscale flow-through mode
Publisher: Elsevier BV
Date: 09-2009
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Discovery Projects - Grant ID: DP140101709
Start Date: 2014
End Date: 12-2017
Amount: $436,000.00
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