New siloxanyl‐modified carbohydrate surfactants of the amide and glycoside type have been synthesized by coupling between defined as well as higher‐molecular‐weight siloxanes and carbohydrate structures via spacers of different lengths and hydrophilic power. Linear and branched monohydrogen di‐, tri‐, tetra‐ and penta‐siloxanes and polyhydrogen siloxanes as well as mono‐ and di‐saccharide lactone structures have been found to be good starting materials for the synthesis of amides, often in quantitative yield, whereas glycosides had to be prepared in low‐yield multistep sequences including protection/deprotection steps. Selected strategies were applied to polysiloxanes yielding quantitatively a broad variety of carbohydrate‐modified comb‐like structures. The new substances were characterized by means of 13C NMR spectroscopy, GC, capillary GC, GC–MS coupling and elemental analysis.
Branched siloxanyl‐modified carbohydrate surfactants have been synthesized by coupling mono‐, di‐ and poly‐functional siloxanes to carbohydrate units either via a branched spacer or by attaching a separate modifying element to a straight‐chained structure. Hydrophilic as well as extremely hydrophobic elements have been incorporated successfully. Siloxanyl‐modified carbohydrates bearing a secondary amino function were alkylated in regioselective reactions by different epoxides ranging from glycidol‐ to siloxanyl‐modified allyl glycidyl ether derivatives. Alternatively, carbohydrate‐modified piperazinyl structures yielded cyclic subunits after alkylation. Structures bearing two identical hydrophilic groups are accessible by alkylation of carbohydrate‐modified bisamides. The derivatives synthesized were characterized by means of GC, NMR and elemental analysis.
Sr3B2O6 kristallisiert wie Ca3B2O6 in der Raumgruppe R3c mit den Gitterkonstanten a0 = 899,9 pm und c0 = 1 248,7 pm, was anhand röntgenographischer Daten aus Pulveraufnahmen des Sr3B2O6 und mit den Strukturdaten des Ca3B2O6 gezeigt wird.
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