Lactose derivatives

Further improvements were obtained by using a simplified strategy based on the use of relatively simple lactose derivatives (Fig. 40).309 The potent monovalent... 

O-allyl glucosamine building block 68. Finally, the controlled hydrogenolysis concept was applied to the synthesis of lactose derivatives (Scheme 4.17). 

Scheme 4.17 Application of the controlled hydrogenolysis concept in lactose derivative synthesis.

Glen, A. Leigh, D. A. Martin, R. P. Smart, J. P. Trascello, A. M., The Regioselective Tert-Butyldimethylsilylation of the 6 -Hydroxyl Group of Lactose Derivatives Via Their Dibutylstannylene Acetals. Carbohydr. Res. 1993,248, 365-369. 

Nishimura and Yamada [10-11] introduced a water-soluble polymeric support having a linker recognized by ceramide glycanase for a synthesis of ganghoside GM3 (17). Synthesis of the polymerizable lactose derivative (14) with a ceramide glycanase sensitive linker is shown in Scheme 10.3. The lactosyl ceramide (Lac-Ger) mimetic glycopolymer (15) is obtained from the monomeric precursor (14) by co-polymerization with acrylamide. 

Mechanism of Action A lactose derivative that retains ammonia in colon and decreases serum ammonia concentration, producing osmotic effect. Therapeutic Effect Promotes increased peristalsis and bowel evacuation, which expels ammonia from the colon. 

Whey powders, demineralized whey powders, whey protein concentrates, whey protein isolates, individual whey proteins, whey protein hydrolysates, neutraceuticals Lactose and lactose derivatives Fresh cheeses and cheese-based products Functional applications, e.g. coffee creamers, meat extenders nutritional applications Whey powders, demineralized whey powders, whey protein concentrates, whey protein isolates, individual whey proteins, whey protein hydrolysates, neutraceuticals Various fermented milk products, e.g. yoghurt, buttermilk, acidophilus milk, bioyoghurt... 

In the initial studies, as briefly described earlier, the methyl a-2-thioglycoside of Neu5Ac 5 [22,24], or the -1 1 anomeric mixture 11 [26,27], which can be almost quantitatively prepared from 9 in one step, was coupled with lightly protected sugar acceptors such as 14,16, and 18 in the presence of DMTST in acetonitrile to give exclusively the sialyl a(2—>3)- or sialyl ot(2—>6)-D-galactose or lactose derivatives (20, 22, and 24) in 50-70% yields even in large-scale reactions [26],... 

A. Hasegawa, T. Nagahama, H. Ohki, K. Hotta, H. Ishida, and M. Kiso, Reactivity of glycosyl promoters in a-glycosylation of W-acetylneuraminic acid with the primary and secondary hydroxyl groups in the suitably protected galactose and lactose derivatives, J. Carbohydr. Chem. 70 493 (1991). 

Scholnick, F. and Linfield, W. M. 1977. Lactose-derived surfactants. III. Fatty esters of oxyalkylated lactitol. J. Am. Oil Chemists Soc. 54, 430-432. 

The 8-methoxycarbonyloctyl derivative of lactose has been prepared from lactose octaacetate in the presence of tin(lV) chloride or from acetobromolactose in the presence of silver triflate [123,124] and converted into the derivative (108) with a free 4 -hydroxyl group [125] via the 4, 6 -0-benzylidene derivative. The benzyl lactoside (109) was converted into the benzyl ether (110) by the action of benzyl bromide and tetrabutylammonium bromide on the dibutylstannylene derivative [126] and this was converted into the benzoate (111). Phase transfer benzylation of the benzyl lactoside (112) has given the lactose derivative (113) with a free 3-hydroxyl group in 38% yield [118]. 1,6-Anhydrolactose has also been used for the preparation of the protected lactose derivative (114) [127]. 

The open-chain derivative (115) of lactose prepared by the action of dimethoxy-propane [128-130] has also been used to prepare the lactose derivative (116) containing a free 2 -hydroxyl group [131]. 

Reist and co-workers [134] condensed the galactosyl bromide [117] with the protected galactose derivative (119) under halide ion-catalysed conditions [25] to give the disaccharide (120) and this was deprotected, acetylated and acetolysed to give the acetylated gal-a-fl - 4)-gal disaccharide (121). Under similar conditions, condensation of (117) with the protected lactose derivative (106) gave the trisaccharide (122) [116] and this was converted into the acetylated methyl glycoside (123) contain-... 

Acetolysis of (241) and subsequent treatment of the 1,6-di-O-acetate produced with titanium(IV) bromide gave the a-glycosyl bromide (247). This was condensed with the lactose derivative (248) (substitution with deuterated benzyl groups made it possible to interpret the NMR spectra [185]) in the presence of silver carbonate — silver perchlorate to give the a-linked pentasaccharide (249) in 38 % yield, and this was deprotected to give (236). 

Ogawa and co-workers [97] have synthesised the complete glycosphingolipid (361) containing the terminal tetrasaccharide (356) of the Leb antigen attached to lactosyl ceramide. The lactose derivative (95), prepared by the action of trimethylamine — borane and aluminium chloride [99] on the benzylidene derivative (94), was condensed with the thioglucoside (362) in the presence of methyl triflate and molecular sieve to give the trisaccharide (363). This was deacetylated and the product (364) condensed... 

Paulsen and von Deessen [272] improved the yield using the bromide (371) instead of the chloride (370) in condensations with the lactose derivative (96) in the presence of silver carbonate — silver perchlorate (30 1) and molecular sieve in toluene at... 

Because of the high nucleophilicity 46 is trapped by means of fast irreversible anomeric O-alkylation and leads to 50.3 23 In general the equatorial oxygen bears the highest nucleophilicity under these reaction conditions. Accompanying the O-silyl group rearrangement and the anomeric benzylation excess NaH and benzyl bromide provides fully benzyl protected lactose derivative 9. 

As one of the effects of the Common Agricultural Policy has been to increase the price of all milk products there has been some substitution of skim milk powder by products derived from whey. Impure grades of spray dried lactose derived from whey are offered as a confectionery ingredient. 

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