Aldobiuronic acids

Lupescu, N., Solo-Kwan, J., Christiaen, D., Morvan, H., and Arad, S. M. (1992). Structural determination by means of gas chromatography-mass spectrometry of 3-0-(a-D-gluco-pyranosyluronic acid)-galactopyranose, an aldobiuronic acid derived from Porphyridium sp. polysaccharide. Carbohydr. Polym. 19 131-134. 

M. Jaseja, A. S. Perlin, O. Dubinsky, D. Christiaen, S. S. (Malis) Arad, andR. Glaser, N.m.r. structure determination of 3-0-(a-D-glucopyranosyluronic acid)-L-galactopyranose, an aldobiuronic acid isolated from the unicellular red alga Rhodella reticulata, Carbohydr. Res., 186 (1989) 313-319. 

The presence of uronic acid groups significantly reduces the hydrolysis rate of glycosidic linkages (Table 2). Thus, high yields of aldobiuronic acid dimers were obtained on partial hydrolysis of xylans [18, 19, 242]. The hydrolysis rate of different hardwood xylans was closely related to their uronic acid content [257]. A higher stability of softwood xylan as compared to... 

As mentioned earlier, hydrolysis of the aldobiuronic acid unit usually involves decomposition of the uronic acid portion. Neutral monosaccharides may also decompose by the action of mineral acids. Pentoses and hexoses form furfural and hydroxymethylfurfural, respectively, by the cyclization-dehydration reaction shown below (32). 

The n.m.r. spectra of five aldobiuronic acid derivatives, and 5-0-jS-D-primeverosyl genkwanine (8) and its acetate have been determined. 

Acetylated derivatives have been used in the characterization of dialdose dianhydrides, partially methylated heptitols, and aldobiuronic acid methyl ester methyl glycosides. The origin of the fragments with even mass numbers derived from alditol acetates is based on elimination of keten, acetic acid, and acetic anhydride. ... 

Sulfated polysaccharide antibiotic of unknown struct. Composed of two types of repeating disaccharide units O-rhamnosylacofriose and O-hexuro-nosylrhamnose (aldobiuronic acid). Characterised as the Ca deriv. Calcium spirulan, to which CAS no. refers. Isol. from the blue-green alga Spirulina platensis. Antiviral agent. Amorph. powder, (as Ca deriv.). [a]o +14.7 (c, 0.6 in H2O) (Ca deriv.). 

A high yield of 1,4-jS-linked product was obtained when methyl 2,3-anhydro-j3-D-ribopyranoside was condensed with 3,4-di-0-acetyl-2-0-benzyl-a-D-xylopyranosyl bromide, and use of tri-O-acetyl-a-D-xylopyranosyl bromide afforded the related product which, on base-catalysed hydrolysis, gave the methyl jS-xylobioside. Several 2-0-glycosyl-D-arabinoses have been prepared by glycosylation of benzyl 3,4-0-isopropylidene-j8-D-arabinopyranoside, and from benzyl 2-0-j3-D-glucopyranosyl-jS-D-arabinoside the aldobiuronic acid was produced. ... 

D-galactose, and three aldobiuronic acids. Ara-binogalactan consists of 75% L-arabinose, 12% D-galactose, 3% D-galacturonic acid, and small amounts of L-ihamnose. Bassorin is reported to contain about 5% methoxyl groups (list and horhammer). " ... 

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