Glycosides, enzymatic cleavage

The Shen group has devised a domino process wherein after an enzymatic cleavage of a glycoside a rearrangement sequence takes place [18]. Subjecting multifloroside 8-38 to P-glucosidase in acetate buffer (Scheme 8.10) afforded jasmolac-tone analogues such as 8-39 in a rather low yield. 

The fhioethyl group present in the anchor group of (40) was activated by treatment with N-iodosuccinimide (NIS) followed by displacement with a variety of alcohols (44-46). To prove the possible application of this linker in solid phase carbohydrate synthesis, protected glycosides (47) and (48) were coupled to linker (40) and released enzymatically. Flitsch et al. also described the immobilization and enzymatic cleavage on a variety of amines [41]. Nevertheless, the application of this enzyme-labile hnker group in multi-step syntheses on the solid phase and subsequent enzyme-initiated release from the polymeric support has not been described yet. 

S. G. Withers, Enzymatic cleavage of glycosides How does it happen, Pure Appl. Chem., 61 (1995)... 

CgFIgOs, Mr 152.15, pi.3kPa 155 °C, df 1.056, is found in many essential oils and foods, but is often not essential for their odor or aroma. However, it does determine the odor of essential oils and extracts from Vanilla planifolia and V. tahitensis pods, in which it is formed during ripening by enzymatic cleavage of glycosides. 

Stephen G. Withers (Canada) Enzymatic cleavage and formation of glycosidic bonds from glycosidases and lyases to transferases and glycosynthases 2004—Made jointly to Anne Imberty (France) and Thomas Peters (Germany) Forty ways to bind your sugar ... 

Enzymatic Cleavage of Plant Glycosides by Hydrolases. In many fruits and other plant tissues oxygenated norisoprenoids (so-called "polyols"), like other secon-... 

The first lipophilicity-activity relationship was published by Charles Richet in 1893, exactly 100 years ago. From his quantitative investigations of the toxicities of ethanol, diethyl ether, urethane, paraldehyde, amyl alcohol, acetophenone, and essence of absinthe ( ) he concluded plus Us sont solubles, mains Us sont toxiques (the more they are soluble, the less toxic they are). One year later Emil Fischer derived the lock and key model of ligand-enzyme interactions from his results on the stereospecificity of the enzymatic cleavage of anomeric glycosides. 

Both zanamivir and oseltamivir are structurally similar to Al-acetyl neuraminic acid (NeuSAc), mimicking the high-energy ojycarbenium intermediate 20, generated during the enzymatic cleavage of the a-glycosidic bond of NeuSAc. 

Enzymatic cleavage of the glycosidic linkage is specified by the configuration on anomeric C-1 and also by the whole glycosyl moiety, while the aglycone residue may vary within limits. 

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