Chiral analogs of enterobactin with hydrophilic or lipophilic properties

Tse, Bruno; Kishi, Yoshito

doi:10.1021/ja00070a051

Cited by 39 publications

(20 citation statements)

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“…The anisotropic thermal parameters of Si revealed almost isotropic atomic displacement and gave no hint to any disorder. The number of independent Si positions is consistent with the findings of Tse, Desando, Ripmeester & Handa (1993), who reported five 29Si MAS-NMR signals, the heights of which (1:4:4:4:4) agree with the multiplicity of the sites (4a) and (163') in the space group 141/a. It should be noted, however, that despite this correspondence our space-group assignment is clearly distinct from the space group 14~/amd, suggested by Tse, Desando, Ripmeester & Handa (1993).…”

Section: Resultssupporting

confidence: 90%

“…Depending upon the size and shape of the enclathrated molecules, different crystal metrics have been found at ambient conditions (Gies, 1984). A variety of reversible phase transitions is also known to exist from experiment-Present address: Hahn-Meitner Institut, NE, Glienicker Strasse 100, D-14109 Berlin, Germany. tal methods, such as differential scanning calorimetry (DSC) or 29Si MAS-NMR (Ripmeester, Desando, Handa & Tse, 1988;Tse, Desando, Ripmeester & Handa, 1993).…”

Section: Introductionmentioning

confidence: 99%

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Room-Temperatrue Structure and Geometrical Analysis of the Cubic–Tetragonal Phase Transition in Dodecasil 3C-THF

Knorr¹,

Depmeier²

1997

Acta Crystallogr Sect B

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The structure of dodecasil 3C-tetrahydrofuran [Si68O136]·4M, M = (CH2)4O, at room temperature was determined from a merohedrally twinned crystal in the tetragonal space group I41/a. The deformation of the ideal framework at the cubic tetragonal phase transition at T c ≃ 365 K could be explained mainly by two different symmetry-breaking processes. (i) A tetragonal tetrahedron distortion of the Si(5) tetrahedra and (ii) a hitherto unknown local one-dimensional tilt mechanism, localized in the tetrahedral network. The location of the axes of this tilt system coincides with the positions of the fourfold inversion axes in the space group I41/a. At room temperature the tilt angle is = 24°. The symmetry properties of the tilt system can explain the reduction of space-group symmetry from the space group of the ideal structure Fd\overline 3m to the space group at ambient conditions I41/a. The guest molecule tetrahydrofuran does not fit the cage symmetry and has been found to be dynamically disordered. The average structure shows an off-center location in the [51264] cage and follows the local \overline 4symmetry of the cage.

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Section: Resultssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Room-Temperatrue Structure and Geometrical Analysis of the Cubic–Tetragonal Phase Transition in Dodecasil 3C-THF

Knorr¹,

Depmeier²

1997

Acta Crystallogr Sect B

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“…Die Gruppe um Murakami [113] verknüpfte ein Hexapus-Cyclophan als C 3 -symmetrisches Grundgerüst über Alaninreste mit den koordinierenden Catecholat-Segmenten (L48). Die l-Form der Aminosäure führte zu Eisen(iii)-Komplexen [114] Mit dem (S)-Enantiomer entstand bevorzugt der D-konfigurierte Komplex. Die Überprüfung der stereochemischen Präferenzen erfolgte an den isostrukturellen, diamagnetischen Ga III -Komplexen.…”

Section: Komplexe Sechszähniger Ligandenunclassified

Prädeterminierte Chiralität an Metallzentren

1999

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Die asymmetrische Synthese in der Koordinationschemie wurde bereits 1920 durch Smirnoff klar beschrieben, aber anders als in der Organischen Chemie wurde die Möglichkeit der asymmetrischen Synthese in der Koordinationschemie über Jahrzehnte kaum genutzt. In jüngster Zeit hat das Interesse an Chiralität in der Koordinationschemie (siehe das Stereobild von [Ru(bpy)3]2+) aus mehreren Gründen stark zugenommen (mehrkernige Systeme, supramolekulare Strukturen und enantioselektive Katalysatoren). Hier wird an einer Vielzahl von Beispielen gezeigt, wie die Ligandenwahl die Konfiguration eines Metallzentrums oder die Chiralität eines Helicates vorherbestimmt.

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“…Similar to myo-inositol, phosphate esters of scyllo-inositols have been prepared synthetically. 13 Due to the C 3 symmetry of the orthoester derivatives, the hexol scaffold has been used in the preparation of glycodendrimers, 14 drug delivery compounds, 15 siderophore (enterobactin) analogs, 16 and hetero-bimetallic catalysts. 17 There is only a small number of examples in which scyllo-inositol is present in an asymmetric form, 1 and axinelloside A (5) stands out due to its intriguing chemical structure and biological activity.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of asymmetrically substituted scyllo -inositol

Rodriguez

Walczak

2016

Tetrahedron Letters

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a b s t r a c t scyllo-Inositol, a rare member of the inositol family, is present in axinelloside A, a marine metabolite with interesting inhibitory activity against human telomerase. Here, we present a concise synthesis of asymmetrically substituted scyllo-inositol starting from inexpensive D-glucose. Our synthetic approach capitalizes on Ferrier rearrangement of vinyl acetate and stereoselective reduction of the resultant ketone to establish the scyllo-inositol core. The protocol provides access to large quantities of scyllo-inositol in 10 steps from commercially available materials. IntroductionInositols are a class of nine distinct isomers of 1,2,3,4,5,6-cyclohexanehexol in which the configuration of the hydroxyl group is permutated giving rise to seven meso and two chiral isomers. 1 Among the members of this family, myo-inositol (1) and its derivatives are the most studied inositols due to their role as secondary messengers (in the form of phosphates and pyrophosphates) and their presence in glycoconjugates (e.g., glycosylphosphatidylinositol (GPI) anchors). 2 However, scyllo-inositol (2), an isomer with all hydroxyl groups in equatorial configuration, is less explored. 1 The parent compound is found at high concentrations in human brain, 3 and has been implicated in certain neurological disorders. 1 There are numerous reports describing the use of scyllo-inositol as a potential drug targeting Alzheimer's 4 and Parkinson's diseases, 5 and research in this area is a topic of current interest. 6 For instance, orally administered scyllo-inositol inhibited the aggregation of amyloid-b (Ab) 7 and prevented the formation of insoluble amyloid fibers believed to cause neuronal dysfunction in Alzheimer's disease. Derivatives of scyllo-inositol (including fluorinated analogs 8 ) have been investigated, among which the hexaphosphate has been identified as a promising drug candidate.From the synthetic standpoint, the conversion of myo-inositol into scyllo-inositol by Kishi 9 is a practical route to prepare large quantities of symmetrical scyllo-inositol from an inexpensive starting material. 10 Other studies by Ikegami 11 and Altenbach 12 provided the parent hexols using glucose or p-quinone as the substrates. Similar to myo-inositol, phosphate esters of scyllo-inositols have been prepared synthetically. 13 Due to the C 3 symmetry of the orthoester derivatives, the hexol scaffold has been used in the preparation of glycodendrimers, 14 drug delivery compounds, 15 siderophore (enterobactin) analogs, 16 and hetero-bimetallic catalysts. 17 There is only a small number of examples in which scyllo-inositol is present in an asymmetric form, 1 and axinelloside A (5) stands out due to its intriguing chemical structure and biological activity. 18 This polysulfated oligosaccharide was isolated from a marine sponge Axinella infundibula, and its structure was proposed based on 1D and 2D NMR studies. The unique features of this molecule are the presence of ten 1,2-cis glycosidic bonds, four fatty acid chains, and the eastern part ter...

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Chiral analogs of enterobactin with hydrophilic or lipophilic properties

Cited by 39 publications

References 0 publications

Room-Temperatrue Structure and Geometrical Analysis of the Cubic–Tetragonal Phase Transition in Dodecasil 3C-THF

Room-Temperatrue Structure and Geometrical Analysis of the Cubic–Tetragonal Phase Transition in Dodecasil 3C-THF

Prädeterminierte Chiralität an Metallzentren

Synthesis of asymmetrically substituted scyllo -inositol

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