18490-93-2Relevant academic research and scientific papers
Stereoselective ring-opening of acetylated pyranose-1,2-(ethyl orthoacetates)
Saito,Sumita,Ichinose,Kanda
, p. 90 - 96 (1993)
When acetylated pyranose-1,2-(ethyl orthoacetates) were hydrolyzed in acidic solvents, the ring-opening of the orthoacetate rings was influenced by the axial or equatorial OAc group at C-4 on the pyranoses; on acid-catalyzed hydrolysis, 3,4,6-tri-O-acetyl-α-D-galactopyranose- (8) and methyl 3,4-di-O-acetyl-α-D-galacturonatopyranose-1,2-(ethyl orthoacetate) (16) having an axial OAc group at C-4 on the pyranose rings gave 1,3,4,6-tetra-O-acetyl-α-D-galactopyranose (9) and methyl 1,3,4-tri-O-acetyl-α-D-galacturonatopyranose (23), respectively, whereas 3,4,6-tri-O-acetyl-α-D-glucopyranose- (10) and methyl 3,4-di-O-acetyl-α-D-glucuronatopyranose-1,2-(ethyl orthoacetate) (22) having an equatorial OAc group at C-4 on the pyranose rings gave 2,3,4,6-tetra-O-acetyl-D-glucopyranose (11) and methyl 2,3,4-tri-O-acetyl-D-glucuronatopyranose (24), respectively. On the acid-catalyzed hydrolysis, 3,4-di-O-acetylβ-L-arabinopyranose-1,2-(ethyl orthoacetate) (34) having an axial OAc group at C-4 on the pyranose ring gave a mixture of 1,3,4-tri-O-acetyl-β-L- (35) and 2,3,4-tri-O-acetyl-L-arabinopyranose (36). These selectivities of ring-opening of the 1,2-(orthoacetates) were considered to have resulted from the differences of the conformers of the 1,2-(orthoacids) intermediates derived from the 1,2-(orthoacetates) and the orientation of the acetyl groups at C-4 on the pyranose rings.
A New Synthesis of D-Glycosiduronates from Unprotected D-Uronic Acids
Bertho, Jean-Noel,Ferrieres, Vincent,Plusquellec, Daniel
, p. 1391 - 1394 (2007/10/02)
O-Glycosidation of totally O-unprotected D-galacturonic acid 1 in THF provides α-pyranosides 4a when promoted with BF3*OEt2 whereas β-furanosides 6β were obtained in the presence of FeCl3; when the same reaction is performed with D-glucuronic acid 2 or 'D-glucurone' 3, alkyl-D-glucofuranosidurono-6,3-lactones 7 are synthesized in excellent yields and high β-selectivity.
The preparation and susceptibility to hydrolysis of novel O-galacturonoyl derivatives of carbohydrates
Brown, John A.,Fry, Stephen C.
, p. 95 - 106 (2007/10/02)
D-Galacturonic acid or (1->4)-α-D-galacturonan reacted in aqueous pyridine in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide with alcohols to yield esters.The alcohols that gave high yields of D-galacturonoyl derivatives were primary and included methanol, ethanol, 1-propanol, D-glucose, D-galactose, methyl β-D-glucopyranoside, methyl β-D-galactopyranoside, and cellulose.D-Galacturonic acid itself readily gave an O-D-galacturonoyl-D-galacturonic acid.The proposed structure of one compound, methyl 6-O-D-galacturonoyl-β-D-glucopyranoside, was supported by 1H and 13C NMR data and the FAB mass-spectral data.Each ester was hydrolysed at pH 11 and 25 deg C within 1 h.O-D-Galacturonoyl-D-glucose was considerably more alkali labile than O-polygalacturonoyl-D-glucose, and O-D-galacturonoylcellulose had an intermediate stability.The esters were relatively stable to cold acid, but could be hydrolysed by M trifluoroacetic acid at 100 deg C for 1 h.The esters tested were resistant to digestion by "Driselase", although the glycosidic bonds of O-polygalacturonoyl D-glucose were hydrolysed to yield O-oligogalacturonoyl-D-glucoses of low molecular weight.The possible application of these analytical methods to the detection of O-uronoyl-type cross-links in cell-wall polysaccharides is discussed.
METHANOLYSIS STUDIES OF CARBOHYDRATES, USING H.P.L.C.
Cheetham, Norman W. H.,Sirimanne, Padmini
, p. 1 - 10 (2007/10/02)
An h.p.l.c. system that separates carbohydrates as their methyl glycosides has been used to study the products obtained on treatment of various carbohydrates with methanolic hydrogen chloride.Results are presented for the monosaccharide composition of several polysaccharides, lactone and ester formation during the treatment of D-glucuronic acid, and relative rates of glycosidation vs. esterification during the treatment of D-galacturonic acid.
