- Glycolipid ester-type heterodimers from Ipomoea tyrianthina and their pharmacological activity
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Tyrianthins A (1) and B (2), two new partially acylated glycolipid ester-type heterodimers were isolated from Ipomoea tyrianthina. Scammonic acid A was determined as the glycosidic acid in both monomeric units. Tyrianthin A (1) (IC50 0.24 ± 0.0
- Leon-Rivera, Ismael,Miron-Lopez, Gumersindo,Estrada-Soto, Samuel,Aguirre-Crespo, Francisco,Gutierrez, Maria del Carmen,Molina-Salinas, Gloria Maria,Hurtado, Gerardo,Navarrete-Vazquez, Gabriel,Montiel, Elizur
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experimental part
p. 4652 - 4656
(2010/04/28)
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- Novel coumarin and chromene compounds and methods of preparation and use thereof for treating or preventing viral infections
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The present invention relates to methods of preparation and use of coumarin and chromene compounds for treating or preventing viral infections.
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- Methods for preparing antiviral calanolide compounds
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The present invention relates to methods for preparing 2,2-dimethyl-5-acyloxy-10-propyl-2H,8H-benzo[1,2-b:3,4-b′]dipyran-8-one (5) and 2,2-dimethyl-5-hydroxy-10-propyl-2H,8H-benzo[1,2-b:3,4-b′]dipyran-8-one (6) and their use as intermediates for the synthesis of antiviral calanolide compounds. For example, Fries rearrangement on compound 5 or Friedel-Crafts reaction on 6, yields intermediate 2,2-dimethyl-5-hydroxy-6-propionyl-10-propyl-2H,8H-benzo[1,2-b:3,4-b′]dipyran-8-one (4), which, in turn, can be converted to (+)-calanolide A and (?)-calanolide B. The coupling of compound 6 with the appropriate chiral molecule under Mitsunobu or nucleophilic displacement leads to the asymmetric synthesis of antiviral calanolide compounds.
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- Methods for preparing antiviral calanolide compounds
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The present invention relates to methods for preparing 2,2-dimethyl-5-acyloxy-10-propyl-2H,8H-benzo[ 1,2-b:3,4-b ′]dipyran-8-one (5) and 2,2-dimethyl-5-hydroxy- 10-propyl-2H,8H-benzo[1,2-b:3,4-b ′]dipyran-8-one (6) and their use as intermediates for the synthesis of antiviral calanolide compounds. For example, Fries rearrangement on compound 5 or Friedel-Crafts reaction on 6, yields intermediate 2,2-dimethyl-5-hydroxy-6-propionyl-10-propyl-2H,8H-benzo[1,2-b:3,4-b′]dipyran-8-one (4), which, in turn, can be converted to (+)-calanolide A and (?)-calanolide B. The coupling of compound 6 with the appropriate chiral molecule under Mitsunobu or nucleophilic displacement leads to the asymmetric synthesis of antiviral calanolide compounds.
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- CHIRAL PROPIONATE ENOLATE EQUIVALENTS FOR THE STEREOSELECTIVE SYNTHESIS OF THREO- OR ERYTHRO-α-METHYL-β-HYDROXY ACIDS.
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The aluminium and copper enolates derived from (n5-C5H5)Fe(CO)(PPh3)COCH2CH3 are chiral propionate enolate equivalents which on reaction with aldehydes (RCHO, R=Me, Et, iPr, tBu) provide stereoselective sytheses of threo-
- Davies, Stephen G.,Dordor-Hedgecock, Isabelle M.,Warner, Peter
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p. 2125 - 2128
(2007/10/02)
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- STEREOSELECTIVE REDUCTION OF 3-OXO AMIDES WITH ZINC BOROHYDRIDE
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2-Alkyl-3-oxo amides were reduced to the corresponding syn-2-alkyl-3-hydroxy amides with high stereoselectivity by zinc borohydride.
- Ito, Yoshio,Yamaguchi, Masaru
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p. 5385 - 5386
(2007/10/02)
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- Methods for the Stereoselective Cis Cyanohydroxylation and Carboxyhydroxylation of Olefins
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Two valuable reagents for the cis-specific vicinal cyanohydroxylation and carboxyhydroxylation of olefins are described.The cyanohydroxylation process is based on the decarboxylative ring opening of 3-carboxyisoxazolines prepared by the cycloaddition reaction of carbethoxyformonitrile oxide with various alkenes.Fragmentation of the isoxazolines prepared from cis- and trans-2-butene has been found to occur without any crossover in stereochemistry.The carboxyhydroxylation process begins with the dipolar cycloaddition reaction of the nitrile oxide derived from thetetrahydropyranyl ether derivative of 2-nitroethanol.Deprotection, hydrogenation, and oxitative cleavage of the derived dihydroxy ketone yield the stereochemcally pure β-hydroxy carboxylic acid.
- Kozikowski, Alan P.,Adamczyk, Maciej
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p. 366 - 372
(2007/10/02)
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