Glycosides alcohols

Phenolic acids and their glycosides Alcohol and water mixtures rather than pure alcohols [22]... 

Reactions in carbohydrates can occur at the carbonyl group or at one of the several alcohols. Aldehydes can be oxidized or reduced. They also can react with amines to form imines. The alcohols can be alkylated or acylated. Selective protection of the glycoside alcohols is possible with careful manipulation of protecting groups. 

Shelf-stable glycosyl N,N,N, N -tetramethylphosphoroamidates, prepared from both (9-benzyl and O-benzoyl-protected D-glucopyranose and D-galactopyranose, were coupled with a variety of primary and secondary glycoside alcohols in pro-pionitrile in the presence of TMSOTf at -78 °C. 

Trichloroacetonitrile reacts with glycosidic hydroxy groups of protected sugars to form glycosyl trichloroacetimidates (R. R. Schmidt, 1980, 1984,1985,1986 B. Wegmann, 1988). The imidate is substituted by alcohols in the presence of trimethylsilyl trifluoromethanesulfonate... 

The preparalion of glycosides m Ihe laboratory is carried oul by simply allowing a carbohydrate to read wilh an alcohol m Ihe presence of an acid calalysl... 

Section 25 13 Glycosides are acetals compounds m which the anomenc hydroxyl group has been replaced by an alkoxy group Glycosides are easily prepared by allowing a carbohydrate and an alcohol to stand m the presence of an acid catalyst... 

Dowex 2-X8 1.2 0.75 Strongly basic (but less basic than Dowex 1 type) anion exchanger with S-DVB matrix for deionization of carbohydrates and separation of sugars, sugar alcohols, and glycosides. 

Sahcyl alcohol [90-01-7] (saligenin, o-hydroxybenzyl alcohol) crystallizes from water in the form of needles or white rhombic crystals. It occurs in nature as the bitter glycoside, saUcin [138-52-3] which is isolated from the bark of Salix helix S. pentandra S. praecos some other species of willow trees, and the bark of a number of species of poplar trees such as Folpulus balsamifera P. candicans and P. nigra. 

Crocin is a yellow-orange glycoside that is freely soluble in hot water, slightly soluble in absolute alcohol, glycerol, and propylene glycol, and insoluble in vegetable oils. Crocin melts with decomposition at about 186°C and has absorption maxima in methanol at about 464 nm and 434 nm. 

Benzaldehyde Cyanohydrin. This cyanohydrin, also known as mandelonitrile [532-28-5] is a yellow, oily Hquid, insoluble in water, but soluble in alcohol and diethyl ether. Mandelonitrile is a component of the glycoside amygdalin [29883-15-6] a precursor of laetdle [1332-94-7] found in the leaves and seeds on most Prunus species (plum, peach, apricot, etc). In 1832, mandelonitrile was the first cyanohydrin to be synthesized. 

AC2O, FeCl3, Et20, 76-93% yield." These conditions give the acetate of the alcohol, which can then be cleaved by simple basic hydrolysis. The method is also effective for the conversion of r-butyl glycosides to acetates with retention of configuration (80-100% yield). 

Triphenylmethyl thioethers have been formed by reaction of the thiol with triphenylmethyl alcohol/anhydrous CF3COOH (85-90% yield) or with triphenyl-methyl chloride (75% yield). Glycosidic triphenylmethyl thioethers are prepared by displacement of the chloride with TrS N(Bu)4 (tetrabutylammonium triphenylmethanethiolate). ... 

---