The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
Henry N C Wong - One of the best experts on this subject based on the ideXlab platform.
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asymmetric synthesis of 3 3 5 5 tetrasubstituted 1 2 Dioxolanes total synthesis of epiplakinic acid f
Organic and Biomolecular Chemistry, 2014Co-Authors: Xiangyin Tian, Qiong Zhao, Henry N C WongAbstract:The first enantioselective total synthesis of epiplakinic acid F (1) was achieved through a pivotal step involving a radical-mediated asymmetric peroxidation of vinylcyclopropanes with molecular oxygen to construct highly substituted 1,2-Dioxolanes. Subsequent conversions of the chiral 1,2-Dioxolanes led to total synthesis of epiplakinic acid F (1) and the confirmation of its absolute configuration. The enantiomer of epiplakinic acid F methyl ester (2) was also prepared.
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synthetic studies toward plakortide e application of the feldman oxygenation to synthesis of highly substituted 1 2 Dioxolanes
Tetrahedron, 2007Co-Authors: Qiong Zhao, Henry N C WongAbstract:The Feldman radical oxygenation of vinylcyclopropanes is successfully applied to the synthesis of the highly substituted core of the 1,2-dioxolane natural product, plakortide E. The ratio of the desired cis-1,2-dioxolane can be enhanced by choice of cyclopropane substituents.
Yasutaka Ishii - One of the best experts on this subject based on the ideXlab platform.
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n hydroxyphthalimide catalyzed radical addition of 1 3 Dioxolanes and molecular oxygen to alkenes under ambient conditions a new route to β oxycarbonyl compounds
Chemical Communications, 2000Co-Authors: Kazutaka Hirano, Takahiro Iwahama, Satoshi Sakaguchi, Yasutaka IshiiAbstract:A novel catalytic hydroxyacylation of alkenes using 1,3-Dioxolanes and molecular oxygen has been developed, and the reaction of 2-methyl-1,3-dioxolane with methyl acrylate under dioxygen atmosphere in the presence of catalytic amounts of NHPI and Co(OAc)2 produced the corresponding adduct in 81% yield.
Patrick H. Dussault - One of the best experts on this subject based on the ideXlab platform.
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in vitro and in vivo activity of 3 alkoxy 1 2 Dioxolanes against schistosoma mansoni
Journal of Antimicrobial Chemotherapy, 2012Co-Authors: Katrin Ingram, Patrick H. Dussault, Charles E Schiaffo, Wantanee Sittiwong, Evan Benner, Jennifer KeiserAbstract:OBJECTIVES: Compounds characterized by a peroxidic skeleton are an interesting starting point for antischistosomal drug discovery. Previously a series of 3-alkoxy-1,2-Dioxolanes, which are chemically stable cyclic peroxides, demonstrated significant in vitro activity against Plasmodium falciparum. We aimed to evaluate the potential of these compounds against Schistosoma mansoni and elucidate the roles of iron and peroxidic groups in activity. METHODS: Drugs were tested against juvenile and adult stages of S. mansoni in vitro and in vivo. Selected structures were assessed in vitro against schistosomes in the presence of additional iron sources. In addition, drugs were tested in vitro and in vivo against Echinostoma caproni, a non-blood-feeding intestinal fluke. Finally, the activity of non-peroxidic analogues was evaluated. RESULTS: Three Dioxolanes displayed IC(50)s >/=20.1 muM against adult schistosomes and values as low as 4.2 muM against newly transformed schistosomula. Nonetheless, only moderate, non-significant worm burden reductions were observed after treatment of mice harbouring adult infections. Drugs lacked activity against juvenile schistosomes in vivo. Two selected Dioxolanes showed in vitro activity against E. caproni down to concentrations of 5 mg/L, but none of the compounds revealed in vivo activity. All tested non-peroxidic analogues lacked activity in vitro against both parasites. CONCLUSIONS: Selected Dioxolanes presented interesting in vitro activity, but low in vivo activities have to be overcome to identify a lead candidate. Although the inactivity of non-peroxidic analogues underlines the necessity of a peroxide functional group, incubation of adult schistosomes with additional iron sources did not alter activity, supporting an iron-independent mode of activation
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3 alkoxy 1 2 Dioxolanes synthesis and evaluation as potential antimalarial agents
ACS Medicinal Chemistry Letters, 2011Co-Authors: Charles E Schiaffo, Matthias Rottman, Sergio Wittlin, Patrick H. DussaultAbstract:A number of 3-alkoxy-1,2-Dioxolanes exhibit promising levels of antimalarial activity against Plasmodium falciparum. A new route to the 1,2-dioxolane core is reported based on tandem peroxidation/cyclization of enones.
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Lewis acid-mediated displacements of alkoxyDioxolanes: synthesis of a 1,2-dioxolane natural product.
Organic Letters, 1999Co-Authors: Patrick H. DussaultAbstract:Addition of electron-rich alkenes to the peroxycarbenium ions derived from Lewis acid-mediated ionization of 3-alkoxy-1,2-Dioxolanes provides an efficient route for the synthesis of substituted 1,2-Dioxolanes. The methodology is illustrated with a rapid synthesis of a 1,2-dioxolane natural product related to the plakinic acids.
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Reaction of 1O2 with alkoxyallylstannanes: Synthesis of 1,2-Dioxolanes and allyl hydroperoxides
Tetrahedron Letters, 1995Co-Authors: Patrick H. Dussault, U. R. ZopeAbstract:Abstract The reaction of 1 O 2 with chiral alkoxyallylstannanes provides a new route for the stereoselective synthesis of 1,2-Dioxolanes and allyl hydroperoxides. Dioxolane formation, which proceeds through ring opening of the intermediate perepoxide upon migration of the stannyl group, is shown to be favored by the presence of an electron-donating group and by steric factors suppressing the more typical H-ene reaction.
Kazutaka Hirano - One of the best experts on this subject based on the ideXlab platform.
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n hydroxyphthalimide catalyzed radical addition of 1 3 Dioxolanes and molecular oxygen to alkenes under ambient conditions a new route to β oxycarbonyl compounds
Chemical Communications, 2000Co-Authors: Kazutaka Hirano, Takahiro Iwahama, Satoshi Sakaguchi, Yasutaka IshiiAbstract:A novel catalytic hydroxyacylation of alkenes using 1,3-Dioxolanes and molecular oxygen has been developed, and the reaction of 2-methyl-1,3-dioxolane with methyl acrylate under dioxygen atmosphere in the presence of catalytic amounts of NHPI and Co(OAc)2 produced the corresponding adduct in 81% yield.
Michael P Doyle - One of the best experts on this subject based on the ideXlab platform.
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divergence of carbonyl ylide reactions as a function of diazocarbonyl compound and aldehyde substituent Dioxolanes dioxolenes and epoxides
Journal of Organic Chemistry, 2004Co-Authors: Albert E Russell, Jonathan Brekan, Luisa S Gronenberg, Michael P DoyleAbstract:The products from dirhodium(II) acetate-catalyzed reactions between diazocarbonyl compounds and a series of benzaldehydes demonstrate the extent of competition between intramolecular and intermolecular trapping of carbonyl ylide intermediates and the electronic effects that govern these transformations. With dimethyl diazomalonate, competition exists between dioxolane and epoxide formation so that with p-anisaldehyde only epoxide formation is observed and with p-nitrobenzaldehyde only 1,3-dioxolane products are formed. With methyl diazoacetoacetate, intramolecular trapping of the intermediate carbonyl ylide results in the sole production of dioxolenes. However, the vinyldiazoacetate analogue of methyl diazoacetoacetate, as its tert-butyldimethlsilyloxy derivative, only produces epoxides in its reactions with substituted benzaldehydes.
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stereocontrol in intermolecular dirhodium ii catalyzed carbonyl ylide formation and reactions Dioxolanes and dihydrofurans
Journal of Organic Chemistry, 1997Co-Authors: Michael P Doyle, David C Forbes, Marina N Protopopova, Sarah A Stanley, Melissa M Vasbinder, Keith R XavierAbstract:Ethyl diazoacetate undergoes dirhodium(II)-catalyzed reactions with aryl aldehydes to form 1,3-Dioxolanes as mixtures of diastereoisomers in good yields. Carbonyl ylides are reaction intermediates. Catalyst dependent diastereocontrol is observed for reactions with p-nitrobenzaldehyde, but not for those with p-anisaldehyde or benzaldehyde, so that at least with transformations involving p-nitrobenzaldehyde a metal-stabilized ylide is responsible for product formation. Higher yields are obtained with catalysis by dirhodium(II) carboxamidates than with the carboxylates. Diastereoselectivity in 1,3-dioxolane formation that occurs through the “free” ylide can be effectively controlled so that only one diastereomer is produced through the use of 2,6-di-tert-butyl-4-methylphenyl diazoacetate (BDA) or dicyclohexylmethyl diazoacetate (DCM). The thermodynamically least stable all-cis trisubstituted 1,3-dioxolane is the primary product from p-nitrobenzaldehyde “cycloaddition” to the metal-stabilized ylide. Reactions...