Derivatives of lactose

Figure 1.113 The NHS ester-suberate derivative of lactose can be used to add lactose groups to amine-containing molecules. The reaction results in the formation of amide bonds containing terminal lactose groups.

The genes of the operon become coordinately up-regulated or induced when allolactose (an inducer and a derivative of lactose) is present, indicating availability of lactose as a potential source of energy and carbon. 

There are three major chemical derivatives of lactose in which the /3 1-4 linkage remains unbroken. They are lactitol, produced by reduction lactulose, produced by isomerization and lactobionic acid, produced by oxidation. The synthesis and properties of these derivatives have been reviewed (Donar and Hicks 1982). 

The perbenzoyl derivative (105) [114,115] has been prepared via the 4, 6 -0-iso-propylidene derivative of lactose and the methyl lactoside (106) via the 4, 6 -Oben-zylidene derivative [116]. Benzoylation of lactose has given a perbenzoyl derivative with a free 3-hydroxyl group [117, 118]. 

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]. 

U. Westerlind, P. Hagback, B. Tidback, L. Wiik, O. Blixt, N. Razi, and T. Norberg, Synthesis of deoxy and acylamino derivatives of lactose and use of these for probing the active site of Neisseria meningitidis W-acetyltransferase, Carbohydr. Res., 340 (2005) 221-233. 

Fucoayllactose comprises about 10% of the total oligosaccharides and its structure has been established as - 0-a-L-fucop3ranosyl-(l galactopyranosyl-(l —v 4)-D-glucopyranose (18). There is evidence, also, that another fucose derivative of lactose exists. < >... 

Many lactose esters, including those of long-chain fatty acids, have been prepared by using the respective acid anhydride in either alkali or pyridine, and the respective acid chloride in pyridine. A mixture of lactose and phenyl isocyanate in pyridine gives an octaphenylurethan derivative of lactose. The yellow a and anomers of lactose octakis-[p-(p-nitrophenylazo)benzoate] were prepared for chromatographic studies. ... 

Thus it is clearly visible that they are about 40-50 K higher than the value of Tg evaluated on the basis of dielectric measurements for acetyl derivative of lactose. It is surely related to the fact that molecules of the reduced disaccharide form strong hydrogen bonds and mainly these interactions are responsible for so significant difference in the glass transition temperatures of the both investigated herein carbohydrates. Influence of hydrogen bonds on structural... 

Bifidobacterium spp. are also stimulated by lactulose, a derivative of lactose (Chapter 2) which is not related to bifidus factors I and II. 

Two separate syntheses have been reported for A -acetyl-lactosamine, one via a 1,6 2,3-dianhydride derivative of lactose and the other by ascent of the series from A(-benzyl-3-0- S-D-galactopyranosyl-D-arabinosylamine, and the 3-0-, 4-0- and 6-0-o -D-mannopyranosyl derivatives of A(-acetyl-glucosamine have been reported. ... 

The -(l-azido-napthalene-S-sulphonyl)-hydrazone derivative of lactose was Mcpared for photoaffinity labelling of a lectin from the conger eel. Aldose N-methyI-A -(4-phcnyI- and -p-substituted phenyl-thiazol-2-yl)hydrazones have been prepared and sqipear to have acyclic sugar residues. Tri- and penta-cyclic derivatives such as 92 and 93 were obtained by condensation of free sugars with A -(4-methylquinolin-2-yl)hydrazine or a tetracyclic heteroaromatic hydrazine, respectively, followed by cyclization (catalyzed by FeQa in EtOH). ... 

Arylhydrazone and bis-arylhydrazone derivatives of lactose have been prepared, and their periodate oxidation studied the formation of an osone derivative by hydrazinolysis of the bisbenzoylhydrazone is noted in Chapter 14. ... 

Andersson M, Oscarson S (1993) Synthesis of glycoconjugates by covalent coupling of o-glycopyranosyl-n-hydroxysuccinimide derivatives of lactose to proteins and lipids and polymerization of their parent acryloyl derivatives into acrylamide polymers. Bioctmjug Chem 4(3) 246-249... 

Some difluoromethyl ethers have been prepared (Scheme 1) and the difluoro-methyl ether moiety was found to be stable to aqueous tiifluoroacetic acid under the conditions required for the deprotection of 1. A 6 -0-(2-naphthylmethyl) derivative of lactose has been synthesized as a fluorescence labelled substrate for... 

And 4 -deoxyfluoro derivatives of lactose and their ceramide glycosides have been produced using (trimethylsilyl)ethyl glycosides as intermediates. Some other fluorinated analogues of disaccharides are referred to above. Disaccharides based on olivomycosides have been produced, the key step being as indicated in Scheme 16, the iodine atom being deemed to have participated in the reaction. 

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