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Articles 1 - 9 of 9
Full-Text Articles in Social and Behavioral Sciences
Concise Synthesis Of (-)-Steviamine And Analogues And Their Glycosidase Inhibitory Activities, Nadechanok Jiangseubchatveera, Marc E. Bouillon, Boonsom Liawruangrath, Saisunee Liawruangrath, Robert J. Nash, Stephen G. Pyne
Concise Synthesis Of (-)-Steviamine And Analogues And Their Glycosidase Inhibitory Activities, Nadechanok Jiangseubchatveera, Marc E. Bouillon, Boonsom Liawruangrath, Saisunee Liawruangrath, Robert J. Nash, Stephen G. Pyne
Faculty of Science, Medicine and Health - Papers: part A
A concise synthesis of (−)-steviamine is reported along with the synthesis of its analogues 10-nor-steviamine, 10-nor-ent-steviamine and 5-epi-ent-steviamine. These compounds were tested against twelve glycosidases (at 143 μg mL−1 concentrations) and were found to have in general poor inhibitory activity against most enzymes. The 10-nor analogues however, showed 50–54% inhibition of α-L-rhamnosidase from Penicillium decumbens while one of these, 10-nor-steviamine, showed 51% inhibition of N-acetyl-β-D-glucosaminidase (from Jack bean) at the same concentration (760 μM).
Synthesis, Characterization, And Photophysics Of Oxadiazole- And Diphenylaniline-Substituted Re(I) And Cu(I) Complexes, Raphael Horvath, Michael G. Fraser, Scott A. Cameron, Allan G. Blackman, Pawel Wagner, David L. Officer, Keith C. Gordon
Synthesis, Characterization, And Photophysics Of Oxadiazole- And Diphenylaniline-Substituted Re(I) And Cu(I) Complexes, Raphael Horvath, Michael G. Fraser, Scott A. Cameron, Allan G. Blackman, Pawel Wagner, David L. Officer, Keith C. Gordon
Faculty of Science, Medicine and Health - Papers: part A
Transition-metal complexes of the types [Re(CO)3Cl(NN)], [Re(CO)3py(NN)]+, and [Cu(PPh3)2(NN)]+, where NN = 4,4′-bis(5-phenyl-1,3,4-oxadiazol-2-yl)-2,2′-bipyridine (OX) and 4,4′-bis(N,N-diphenyl-4-[ethen-1-yl]-aniline)-2,2′-bipyridine (DPA), have been synthesized and characterized. Crystal structures for [Re(CO)3Cl(DPA)] and [Cu(PPh3)2(OX)]BF4 are presented. The crystal structure of the rhenium complex shows a trans arrangement of the ethylene groups, in agreement with density functional theory calculations. The structure of the copper complex displays the planar aromatic nature of the bpy–oxadiazole ligand. Density functional theory modeling of the complexes was supported by comparison of calculated and experimental normalized Raman spectra; the mean absolute deviations of the complexes were <10 cm–1. The Franck–Condon state was investigated using UV–vis and resonance Raman spectroscopic as well as density functional theory computational techniques. It was shown that the lowest energy absorption peaks are metal to ligand charge transfer and ligand-centered charge transfer for the oxadiazole- and diphenylaniline-substituted bipyridine ligands, respectively. The lowest energy excited states were characterized using transient emission and absorption spectroscopic techniques in conjunction with density functional theory calculations. These showed that the DPA complexes had ligand-centered nonemissive “dark” states with lifetimes ranging from 300 to 2000 ns.
Concise Synthesis Of Α-Substituted 2-Benzofuranmethamines And Other 2-Subsituted Benzofurans Via Α-Substituted 2-Benzofuranmethyl Carbocation Intermediates, Nikhom Wongsa, Ubonta Sommart, Thunwadee Ritthiwigrom, Arife Yazici, Somdej Kanokmedhakul, Kwanjai Kanokmedhakul, Anthony C. Willis, Stephen G. Pyne
Concise Synthesis Of Α-Substituted 2-Benzofuranmethamines And Other 2-Subsituted Benzofurans Via Α-Substituted 2-Benzofuranmethyl Carbocation Intermediates, Nikhom Wongsa, Ubonta Sommart, Thunwadee Ritthiwigrom, Arife Yazici, Somdej Kanokmedhakul, Kwanjai Kanokmedhakul, Anthony C. Willis, Stephen G. Pyne
Faculty of Science, Medicine and Health - Papers: part A
Propargyl amines 4, where R3 is aryl, undergo 5-exo-dig cyclization reactions under relatively mild conditions (AgNO3, DMF, 60 °C, 1 h) to give 3-amino-2,3-dihydro-2-arylmethylidenebenzofurans 5 (R3 = aryl). In contrast, substrates where R3 is alkyl undergo competing 6-endo-dig and 5-exo-dig cyclization processes. The hydroxymethyl substrate 4 (R3 = CH2OH), however, was smoothly converted to its corresponding 5-exo-dig cyclization product 5, likely due to the assistance of the primary hydroxyl group in the 5-exo-dig cyclization process by silver cation coordination. Under more enforcing conditions (AgNO3, DMF, 100 °C, 18 h), the initially formed products 5 undergo a 1,3-allylic rearrangement to their …
The Boronic Acid Mannich Reaction In Alkaloid Synthesis, Stephen G. Pyne, Andrew S. Davis, Thunwadee Ritthiwigrom, Christopher W. G Au, Kongdech Savaspun, Matthew Wotherspoon
The Boronic Acid Mannich Reaction In Alkaloid Synthesis, Stephen G. Pyne, Andrew S. Davis, Thunwadee Ritthiwigrom, Christopher W. G Au, Kongdech Savaspun, Matthew Wotherspoon
Faculty of Science, Medicine and Health - Papers: part A
Our work on the application of the boronic acid Mannich reaction to the synthesis of pyrrolizidine alkaloids is described.
Climatic Records Over The Past 30 Ka From Temperate Australia - A Synthesis From The Oz-Intimate Workgroup, L Petherick, H Bostock, T J. Cohen, K Fitzsimmons, J Tibby, M -S Fletcher, P Moss, J Reeves, S Mooney, T Barrows, J Kemp, J Jansen, G Nanson, A Dosseto
Climatic Records Over The Past 30 Ka From Temperate Australia - A Synthesis From The Oz-Intimate Workgroup, L Petherick, H Bostock, T J. Cohen, K Fitzsimmons, J Tibby, M -S Fletcher, P Moss, J Reeves, S Mooney, T Barrows, J Kemp, J Jansen, G Nanson, A Dosseto
Faculty of Science, Medicine and Health - Papers: part A
Temperate Australia sits between the heat engine of the tropics and the cold Southern Ocean, encompassing a range of rainfall regimes and falling under the influence of different climatic drivers. Despite this heterogeneity, broad-scale trends in climatic and environmental change are evident over the past 30 ka. During the early glacial period (∼30–22 ka) and the Last Glacial Maximum (∼22–18 ka), climate was relatively cool across the entire temperate zone and there was an expansion of grasslands and increased fluvial activity in regionally important Murray–Darling Basin. The temperate region at this time appears to be dominated by expanded sea ice …
Sequential 1,4- And 1,2-Addition Reactions To Α,Β-Unsaturated N-Acyliminium Ions: A New Strategy For The Synthesis Of Spiro And Bridged Heterocycles, Arife Yazici, Stephen G. Pyne
Sequential 1,4- And 1,2-Addition Reactions To Α,Β-Unsaturated N-Acyliminium Ions: A New Strategy For The Synthesis Of Spiro And Bridged Heterocycles, Arife Yazici, Stephen G. Pyne
Faculty of Science, Medicine and Health - Papers: part A
Novel bicyclic and tetracyclic spirocycles and tricyclic bridged heterocyclic systems can be readily prepared from sequential 1,4- and 1,2-addition reactions of latent bis-nucleophiles to α,β-unsaturated N-acyliminium ions.
Synthesis Of Cephalosporin-3′-Diazeniumdiolates: Biofilm Dispersing No-Donor Prodrugs Activated By Β-Lactamase, Nageshwar Rao Yepuri, Nicolas Barraud, Nasim Shah Mohammadi, Bharat G. Kardak, Staffan Kjelleberg, Scott A. Rice, Michael J. Kelso
Synthesis Of Cephalosporin-3′-Diazeniumdiolates: Biofilm Dispersing No-Donor Prodrugs Activated By Β-Lactamase, Nageshwar Rao Yepuri, Nicolas Barraud, Nasim Shah Mohammadi, Bharat G. Kardak, Staffan Kjelleberg, Scott A. Rice, Michael J. Kelso
Faculty of Science, Medicine and Health - Papers: part A
Use of biofilm dispersing NO-donor compounds in combination with antibiotics has emerged as a promising new strategy for treating drug-resistant bacterial biofilm infections. This paper details the synthesis and preliminary evaluation of six cephalosporin-3′-diazeniumdiolates as biofilm-targeted NO-donor prodrugs. Each of the compounds is shown to selectively release NO following reaction with the bacteria-specific enzyme β-lactamase and to trigger dispersion of Pseudomonas aeruginosa biofilms in vitro.
Synthesis And Inhibitory Activities At Mglurs Of 3-Alkylated And N-Alkylated Cyclopentyl-Glutamate Analogues, Alison T. Ung, Stephen G. Pyne, Francois Bischoff, Anne S. J Lesage, Brian W. Skelton, Allan H. White
Synthesis And Inhibitory Activities At Mglurs Of 3-Alkylated And N-Alkylated Cyclopentyl-Glutamate Analogues, Alison T. Ung, Stephen G. Pyne, Francois Bischoff, Anne S. J Lesage, Brian W. Skelton, Allan H. White
Faculty of Science, Medicine and Health - Papers: part A
The conformationally restricted glutamate analogues, 3-alkyl-1-amino-2-cyclopentene-1,3-dicarboxylates and N-alkylated analogues have been prepared in a regioselective and diastereoselective manner. From the biological studies of the 3-alkylated analogues, compound 13b was found to be the most potent antagonist (IC50 7.7 μM) at mGluR2. Amongst the N-alkylated analogues, compound 20 was found to be a partial agonist (EC50 9.5 μM) and as well as an antagonist (IC50 47 μM) at mGluR2.
Stereoselective Synthesis Of Α-Methylenecyclopentenones Via A Diels-Alder/Retro-Diels-Alder Protocol, Weerachai Phutdhawong, Gedsirin Eksinitkun, Stephen G. Pyne, Anthony C. Willis, Waya S. Phutdhawong
Stereoselective Synthesis Of Α-Methylenecyclopentenones Via A Diels-Alder/Retro-Diels-Alder Protocol, Weerachai Phutdhawong, Gedsirin Eksinitkun, Stephen G. Pyne, Anthony C. Willis, Waya S. Phutdhawong
Faculty of Science, Medicine and Health - Papers: part A
A new procedure for the stereoselective synthesis of cross-conjugated dienones is reported. This method makes use of the Diels–Alder adduct of anthracene and dimethyl fumarate, a precursor to a spirocyclopent-2-enone anthracene adduct as the key intermediate. The addition of propyllithium or octyllithium to the key intermediate followed by a retro-Diels–Alder reaction furnished α-methylenecyclopentenones bearing a γ-propyl or γ-octyl side chain, respectively, in moderate yields and as single geometric isomers.