Galactose 6-deoxy-2-0-methyl

The synthesis of halodeoxy sugars has also been achieved by reaction of sugar phosphorodiamido and phosphonamido derivatives with alkyl halides (83). Heating equimolar amounts of 6-(tetraethylphosphoro-diamido)-l,2 3,4-di-0 isopropylidene-D-galactose with methyl iodide (and benzyl bromide) at 140°C. for 4 hours afforded the 6-deoxy-6-iodo (74b) (75%) and 6-bromo-6-deoxy (74c) (56%) derivatives, respectively. 

S. S. Thomas, J. Plenkiewicz, E. R. Ison, M. Bols, W. Zou, W. A. Szarek, and R. Kisilevsky, Influence of monosaccharide derivatives on liver cell glycosaminoglycan synthesis 3-Deoxy-D-jcy/o-hcxosc (3-deoxy-D-galactose) and methyl(methyl 4-chloro-4-deoxy-p-D-gala-ctopyranosid)uronate, Biochim. Biophys. Acta, 1272 (1995) 37 48. 

The stereoselective requirements for the transport of sugars by these transporters are quite restrictive. The D isomers of mannose, fructose, and galactose appear to interact with both systems however, only D-galactose, a methyl-D-glucoside, and 6-deoxy-D-glucose appear to be transported... 

Phosphate esters of 2-deoxy D-galactose (2-deoxy-D-Zt/xo-hexose) have also been obtained (15). The 6-phosphate (12) was synthesized from the methyl glycoside (9) by condensing the latter with acetone the 3,4-... 

Deoxy-2-[ F]fluoro-D-galactose can be prepared through an addition reaction to tri-O-acetyl-D-galactal (465), but better through Sn2 reaction (K F-Kryptofix 222 in MeCN) of methyl 3,4-0-isopropylidene-2-0-triflyl-6-0-trityl-y -D-talopyranoside (220 see Section 11,2), according to the cold synthesis. 

AW, Acid-washed Choi, Cholesterol DMAP, 4-(Dimethylamino)pyridine DMF, N,/V-Dimethylformamide DMTr, Di(p-niethoxyphenyl)phenyl methyl GalNAc, N-Acetylgalactosamine, 2-acetamido-2-deoxy-D-galactose HMF, 5-Hydroxymethylfur-fural, 5-(hydroxymethyl)-2-furaldehyde INOC, Intramolecular nitrile oxide-alkene cycloaddition Lea, Lewisa Lex, Lewisx MOM, Methoxymethyl MP, p-Methoxyphe-nyl MS, Molecular sieves NIS, N-Iodosuccinimide PCC, Pyridinium chlorochromate PDC, Pyridinium dichromate PMA, Phosphomolybdic acid PMB, p-Methoxybenzyl ... 

A methylation analysis of S14, performed in the authors laboratory,44 gave 2,3,4,6-tetra-O-methyl-D-galactose, 2,4,6-tri-O-methyl-D-galactose, and 2,3,6-tri-O-methyl-D-glucose in the proportions 1 1 1. Although these are the same components as previously reported, the proportions are different. In addition to these sugars, 2-deoxy-3-0-methyl-2-(methylamino)-D-glucose was also obtained. 

The D-galactosyl residues are the same as in disaccharide 33, and the fact that ribitol is substituted at 0-2 was evident from the methyl-ation analysis. Finally, a nonreducing tetrasaccharide was obtained, containing D-galactose, 2-acetamido-2-deoxy-D-galactose, and ribitol residues in the proportions 2 1 1. From these results, and periodate-oxidation studies, structure 36 was proposed for the neutral hexa-saccharide. 

M. W. Homer, L. Hough, and A. C. Richardson, Selective benzoylation of methyl 2-benzamido-2-deoxy-a-D-glucopyranoside A convenient preparation of derivatives of 2-amino-2-deoxy-D-galactose, /. Chem. Soc., Sect. C (1970) 1336-1340. 

Small-intestine lactase (GH 1), the absence of which is associated with lactose intolerance in a large proportion of the adult population, was probed with monodeoxy as well as selected mono-O-methyl derivatives in the galactose moiety of methyl lactosides.112 This enzyme required hydroxyl groups at C-2 and also C-3, while neither the presence of a 4-OH group nor a specific configuration at C-4 was prerequisites for successful hydrolysis. A 6 -deoxy lactoside was readily hydrolyzed, but the absence of 6-OH in the gluco moiety caused it to be a poor substrate. 

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