Die Konstitution der isomeren Acetyldigitoxine. 48. Mitteilung über Herzglykoside

Kühn, Markus; Lichti, H.; Wartburg, A. von

doi:10.1002/hlca.19620450318

Cited by 10 publications

(1 citation statement)

References 32 publications

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“…In the light of the finding that 2-deoxyglucosyl fluoride was the most advantageous of the 2-deoxyglucosyl donors investigated, the corresponding fluorides 5 and 6 ( Figure 1) of 2-deoxylfucose and D-digitoxose were prepared (Scheme 2). To this end, triacetates 25 19 and 26 20 were converted into diacetylated allyl glycosides 27 and 28. After removal of the acetates, benzyl ether protecting groups were introduced.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Deoxy Glycosides Under Neutral Conditions in LiClO4/Solvent Mixtures

Schene¹,

Waldmann

1999

Synthesis

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2-Deoxy-and 2,6-dideoxyglycosyl trichloroacetimidates, phosphites and fluorides are efficiently activated in 0.1M metal perchlorate/solvent mixtures, i. e. without the need for an additional promoter like a strong Lewis acid or a heavy metal salt. Under these neutral conditions they react with different glycosyl acceptors to give oligosaccharides, amino acid glycosides and cholesteryl glycosides in high yields and with pronounced stereoselectivity. For 3,4,6-tri-O-benzyl protected 2-deoxy glucose the highest yields were observed with the a-imidate, however, the anomer ratio was highest if the corresponding glycosyl fluoride was used. The stereoselectivity was not significantly influenced by the solvent and the metal ion, the yield was highest in 0.1M solutions of LiClO 4 in diethyl ether. Under these gentle conditions also 2-deoxy-L-fucosyl fluoride and D-digitoxosyl fluoride react with different O-silylated glycosyl acceptors to give sensitive 2,6-dideoxyglycosides with preparatively useful results.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Deoxy Glycosides Under Neutral Conditions in LiClO4/Solvent Mixtures

Schene¹,

Waldmann

1999

Synthesis

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Besonderheiten der Zucker von herzaktiven Glykosiden

Reichstein

1962

Angewandte Chemie

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Wenn man die Zuckerkomponenten der digitaloiden Lactone (sowie zweier weiterer kleiner Stoffgruppen) mit denjenigen der übrigen natürlichen Glykoside der höheren Pflanzen vergleicht, so ergeben sich auffallende Unterschiede: Nicht digitaloide Glykoside enthalten als Bausteine fast stets einen oder mehrere der acht Zucker D‐Glucose, D‐Glucuronsäure, D‐Xylose, L‐Arabinose, D‐Galactose, D‐Galacturonsäure, L‐Fucose, L‐Rhamnose. Oligosaccharid‐Anteile enthalten fast stets die Hexose „innen”︁, d. h. direkt an das Aglykon gebunden, Pentosen und Methylpentosen „außen”︁. Oligosaccharid‐Anteile mit mehr als zwei Zuckern scheinen oft verzweigt zu sein. In herzaktiven Glykosiden (und zwei verwandten kleinen Stoffgruppen) kommen von den acht Zuckern nur D‐Glucose und L‐Rhamnose häufig vor. Sehr oft werden zahlreiche andere Zucker gefunden, besonders Hexamethylosen. Oligosaccharid‐Anteile enthalten die Hexose (D‐Glucose) immer „außen”︁. Oligosaccharid‐Anteile mit mehr als zwei Zuckern sind, soweit bekannt, immer linear gebaut.

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Special Properties of the Sugars in Cardioactive Glycosides

Reichstein

1962

Angew. Chem. Int. Ed. Engl.

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Dyes with the radical of 2,4,5-trichloropyrimidine (X) are less reactive than dyes of analogous structure containing the radical of symmetrical trichloropyrimidine (IX). This is due to the fact that, even with a chlorine atom in position 5, the chlorines in positions 2 and 6 of (X) are not as reactive as those at position 4 in (IX), since they lack the enhancing effect of resonance in the pyrimidine ring. moieties almost always contain hexoses "on the inside", i. e. linked directly onto the aglycone, and pentoses and mefhyl pentoses "on the outside". Oligosaccharide moieties containing more than two sugars often appear to be branched. Cardioactive glycosides (and two related minor groups of substances) chiefly contain only two sugars of the eight listed, viz. D-glucose and L-rhamnose. Very often numerous other sugars are found, particularly hexamethyloses. Oligosaccharide moieties always contain the hexose (D-glucose) "on the outside". As far as is known, oligosaccharide moieties with more than two sugars are always built up linearly.

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Die Konstitution der isomeren Acetyldigitoxine. 48. Mitteilung über Herzglykoside

Cited by 10 publications

References 32 publications

Synthesis of Deoxy Glycosides Under Neutral Conditions in LiClO4/Solvent Mixtures

Synthesis of Deoxy Glycosides Under Neutral Conditions in LiClO4/Solvent Mixtures

Besonderheiten der Zucker von herzaktiven Glykosiden

Special Properties of the Sugars in Cardioactive Glycosides

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