Total synthesis of the potent immunosuppressant (-)-Pironetin

Dias, Luiz C.; Oliveira, Luciana G. de; Sousa, Márcio Alves de; Ellensohn, Ricardo Machado

doi:10.3998/ark.5550190.0006.607

Cited by 3 publications

(1 citation statement)

References 4 publications

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“…We employed the same strategy to add an allyl group at C-5. Usually, the formation of a C−C bond by displacement of a tosylate group with a Grignard reagent is low yielding or is transition metal-catalyzed, − but in this case the reaction proceeded smoothly at ambient temperature. We believe that allylmagnesium bromide reacts with the intermediate strained bicyclic sulfonium salt to give compound 22 .…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Conformational Analysis of Bicyclic Sulfonium Salts. Structures Related to the Glycosidase Inhibitor Australine

Kumar¹,

Pinto²

2005

J. Org. Chem.

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The syntheses of eight sulfonium compounds with structures related to the naturally occurring pyrrolizidine alkaloid, australine, in which the bridgehead nitrogen atom is replaced by a sulfonium ion, are described. The synthetic strategy relies on the intramolecular attack of a cyclic thioether across a terminal double bond in the presence of a suitable electrophile. We postulate that these compounds, having a permanent positive charge on the sulfur atom, will mimic the highly unstable oxacarbenium ion transition state in a glycosidase-catalyzed hydrolysis reaction. The conformational preferences of these compounds, based on analysis of 1H-1H vicinal coupling constants and 1D-NOESY data, are attributed to both steric and electrostatic interactions. These compounds will be used in the study of structure-activity relationships with glycosidase enzymes.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Conformational Analysis of Bicyclic Sulfonium Salts. Structures Related to the Glycosidase Inhibitor Australine

Kumar¹,

Pinto²

2005

J. Org. Chem.

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Stereoselective syntheses of naturally occurring 5,6-dihydropyran-2-ones

et al. 2007

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Comparative anticancer activity of dolaborane diterpenes from the roots of <em>Ceriops tagal</em> (Rhizophoraceae)

Chacha¹

2012

Int. J. Bio. Chem. Sci

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This study aimed at investigating the anticancer activity of tagalsins A, B, C, D, E, F and G isolated from the roots of Ceriops tagal. Their structures were established based on the IR, MS and NMR spectral data. Anticancer activity was evaluated using caspase-3 colourimetric assays and the minimum activation concentrations were established. The study revealed that tagalsin A, B, C, D, E, F and G induces apoptosis through the activation of caspase-3 enzyme. Tagalsin A was the most active (MAC value of 0.12 µg/mL) followed by tagalsin B (MAC of 0.15 µg/mL) and and tagalsin E was the least active (MAC value of 1.16 µg/mL). Structure activity relationship revealed that epoxide rings and oxygenation enhanced the activity of tagalsins in inducing caspase-3 activation of apoptotic pathway, thus, providing an avenue for the development of anticancer agents with novel mechanism of actions.

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Total synthesis of the potent immunosuppressant (-)-Pironetin

Cited by 3 publications

References 4 publications

Synthesis and Conformational Analysis of Bicyclic Sulfonium Salts. Structures Related to the Glycosidase Inhibitor Australine

Synthesis and Conformational Analysis of Bicyclic Sulfonium Salts. Structures Related to the Glycosidase Inhibitor Australine

Stereoselective syntheses of naturally occurring 5,6-dihydropyran-2-ones

Comparative anticancer activity of dolaborane diterpenes from the roots of <em>Ceriops tagal</em> (Rhizophoraceae)

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