First Glycosylation of Decarestrictine B and D: A Route to Hybrid Antibiotics

Abstract

Abstract:The naturally occurring ten-membered lactones decarestrictine B (4) and D (5), which lower cholesterol levels, were glycosylated with deoxygenated 2-selenoglycosyl acetates 7 a, 7 b, and glycal 10 (obtained from d-glucose), and glycal 13 (obtained from l-rhamnose). Depending on the glycosylation method employed, the triol decarestrictine D was glycosylated with a high degree of regioselectivity. A set of hybrid structures were yielded by O-deblocking and in most cases reductive removal of a halogen or a phenylselenyl group from C-2 of the glycosides 14 a ± f, 20 a, 20 b, and 24. These hybrids were subjected to preliminary biological tests in which the novel glycoconjugates 15 d and 15 e displayed DNA-binding properties.

Total Synthesis of the Postulated Structure of Fulicineroside

“…In the NMR spectroscopic analysis of the glycosylated natural product an emphasis was set on the postulated uncommon β‐linked L ‐rhodinose (Figure 5). Signals for the rhodinosyl‐H‐1′′′ of the β‐linked products 1 ( δ =4.45 ppm) and 88 ( δ =4.53 ppm) were consistent with data of Kirschning50 for a synthetic β‐linked rhodinose ( δ =4.45 ppm) but differed from Řezanka’s value ( δ =4.78 ppm). The latter value matched better with the data for the α‐rhodinose compound 89 ( δ =4.89 ppm) and Kirschning’s data ( δ =4.93 ppm for an α‐rhodinose).…”

Randomized clinical trial of ultrasonicversuselectrocautery dissection of the gallbladder in laparoscopic cholecystectomy

“…Da die Zahl der Resistenzen gegen bekannte Antibiotika zunimmt, wird die Hybridisierung als wichtiger Ansatz zur Entwicklung neuer Therapeutika für Bakterieninfektionen betrachtet. Die Glycosylierung von Decarestrictin D ( 273 ), einem natürlich vorkommenden zehngliedrigen Lacton, mit einem Iodderivat von L ‐Rhodinose ( 274 ), einem der seltenen Zucker, die gewöhnlich als Teilstrukturen in Angucyclin‐Antibiotika auftreten, führte zur Bildung der anomeren Glycoside 275 a und 275 b 99. Erste Ergebnisse sprechen für DNA‐bindende Eigenschaften dieser Hybride.…”

Polymer‐Bound Diphenylphosphane Hydrobromide, a Mild Acid for the Activation of Enol Ethers: Applications in Polymer‐Assisted Glycosidations

“…The Ferrier rearrangement17 is a common side reaction, however, resulting in the undesired unsaturated 2,3‐dideoxy hexoses. Thus, 3,4‐diacylated decarestricine D 4 , obtained by a three‐step protection/deprotection sequence from decarestrictine D ( 17 )16k via intermediates 18 and 19 , was utilized in the first glycosidation procedure (Scheme ). Decarestrictine D ( 17 )18 was first isolated from the fermentation broth of Penicillium species,19 and is a ten‐membered lactone analogue of larger macrolactone antibiotics.…”