Direct Preparation of 1,2:3,5-Di-O-cyclohexylidene-α-D-xylofuranose from Corncobs and Its Conversion to 1-O-Acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose

1994 ◽  
Vol 59 (8) ◽  
pp. 1884-1888 ◽  
Author(s):  
Mirjana Popsavin ◽  
Velimir Popsavin ◽  
Nada Vukojevic ◽  
Dušan Miljković
Keyword(s):  
Acid Hydrolysis ◽  
Hydroxyl Group ◽  
Partial Acid Hydrolysis ◽  
Novel Synthesis ◽  
Direct Preparation ◽  
Acid Methanolysis ◽  
Hydrolysis Of ◽  
Mild Acid

A novel synthesis of 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose (I) has been described starting from 1,2:3,5-di-O-cyclohexylidene-α-D-xylofuranose (II), obtained directly from the crude xylose syrup originated from corncobs. Partial acid hydrolysis of II gave 1,2-O-cyclohexylidene-α-D-xylofuranose (III). Selective benzoylation of primary C-5 hydroxyl group of III followed by tosylation of C-3 hydroxyl group afforded IV in an overall yield of 67%. Mild acid methanolysis of IV gave the corresponding methyl xylofuranosides V which were further benzoylated to afford 2,5-di-O-benzoyl derivatives VI in 65% yield. Solvolysis of VI in 95% DMF gave a mixture of 2,5- and 3,5-di-O-benzoylribofuranosides VII, which were subsequently converted into the corresponding tribenzoates VIII. An acetolysis of VIII afforded I in an overall yield of 96% related to VI.

Structural features of a lipopolysaccharide isolated from Escherichiacoli 086:Kneg.

1970 ◽  
Vol 48 (16) ◽  
pp. 2500-2508 ◽  
Author(s):  
Prem Pal Singh ◽  
G. A. Adams
Keyword(s):  
Acid Hydrolysis ◽  
Lipid A ◽  
Structural Features ◽  
Branch Points ◽  
Mild Acid Hydrolysis ◽  
Partial Acid Hydrolysis ◽  
E Coli ◽  
Glucan Chain ◽  
Hydrolysis Of ◽  
Mild Acid

Lipopolysaccharide (LPS) prepared from Escherichiacoli 086:Kneg., in 5.5% yield contained D-galactose, D-glucose, L-fucose, L-glycero-D-manno-heptose, D-glucosamine, D-galactosamine, 2-keto-3-deoxy-octulosonic acid (KDO) and lipid A. The molecule appeared to be homogeneous as tested by free boundary electrophoresis, ultracentrifugation, and immunodiffusion against ′O′ specific E. coli antiserum. Methylation studies of the LPS and also of the degraded polysaccharides obtained by partial acid hydrolysis showed that the molecule was highly branched. Sixty percent of the D-galactose units were non-reducing terminal groups, the remainder were linked (1 → 3) and (1 → 2) and 3-O-β-D-galactopyranosyl-D-galactose was identified as a product of mild acid hydrolysis of the parent LPS. Fucose occurred in the polysaccharide as (1 → 4) linked units. Methylation results showed that the D-glucose units were linked (1 → 3) and (1 → 4). Partial acid hydrolysis yielded cellobiose, cellotriose, and laminaribiose, showing that the glucose units formed a glucan chain within the polysaccharide and that the glucosidic linkages were in the β-D-configuration. Approximately one half of the L-glycero-D-manno-heptose units occurred as non-reducing end groups, the other half were linked at C-3 and either one of C-6 or C-7. One half of the D-galactosamine units was linked (1 → 3) with the remainder occurring as double branch points. D-Glucosamine residues occurred exclusively in the lipid A moiety in a (1 → 4) linked core structure.

scholarly journals Further studies on the glycerol teichoic acid of walls of Staphylococcus lactis I3. Location of the phosphodiester groups and their susceptibility to hydrolysis with alkali

1971 ◽  
Vol 125 (1) ◽  
pp. 353-359 ◽  
Author(s):  
A. R. Archibald ◽  
J. Baddiley ◽  
J. E. Heckels ◽  
S. Heptinstall
Keyword(s):  
Acid Hydrolysis ◽  
Teichoic Acid ◽  
Hydroxyl Group ◽  
High Yield ◽  
Selective Hydrolysis ◽  
Partial Acid Hydrolysis ◽  
Structural Types ◽  
Phosphodiester Group ◽  
Hydrolysis Of ◽  
Alcoholic Hydroxyl

1. The teichoic acid from walls of Staphylococcus lactis I3 is readily degraded in dilute alkali. 2. Degradation proceeds by selective hydrolysis of that phosphodiester group attached to an alcoholic hydroxyl group of the N-acetylglucosamine and gives a repeating unit in high yield. 3. Further studies on a different repeating unit isolated by partial acid hydrolysis have shown that the glycerol diphosphate is attached to the 4-hydroxyl group of the N-acetylglucosamine and not to the 3-hydroxyl group as was proposed earlier. 4. The susceptibility towards hydrolysis by alkali of other structural types of teichoic acid has been examined and found to vary markedly according to their structure.

Phosphopeptides Obtained by Partial Acid Hydrolysis of α-Casein2

1957 ◽  
Vol 79 (10) ◽  
pp. 2559-2565 ◽  
Author(s):  
N. J. Hipp ◽  
M. L. Groves ◽  
T. L. McMeekin
Keyword(s):  
Acid Hydrolysis ◽  
Partial Acid Hydrolysis ◽  
Hydrolysis Of

Sequential Enzymatic and Mild-Acid Hydrolysis of By-Product of Carrageenan Process from Kappaphycus alvarezii

2019 ◽  
Vol 12 (2) ◽  
pp. 419-432 ◽  
Author(s):  
Fernando Roberto Paz-Cedeno ◽  
Eddyn Gabriel Solórzano-Chávez ◽  
Levi Ezequiel de Oliveira ◽  
Valéria Cress Gelli ◽  
Rubens Monti ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Kappaphycus Alvarezii ◽  
Mild Acid Hydrolysis ◽  
Hydrolysis Of ◽  
Mild Acid

scholarly journals IMMUNOCHEMICAL STUDIES ON BLOOD GROUPS

1971 ◽  
Vol 133 (1) ◽  
pp. 39-52 ◽  
Author(s):  
Ten Feizi ◽  
Elvin A. Kabat ◽  
Giuseppe Vicari ◽  
Byron Anderson ◽  
W. Laurence Marsh
Keyword(s):  
Acid Hydrolysis ◽  
Blood Group ◽  
Ovarian Cyst ◽  
Periodate Oxidation ◽  
Human Saliva ◽  
Mild Acid Hydrolysis ◽  
Group B ◽  
Hydrolysis Of ◽  
Substantial Heterogeneity ◽  
Mild Acid

A partially purified blood group-like substance obtained from milk showed I activity with 2 of 21 anti-I sera. With these antisera, certain human ovarian cyst substances considered to be precursors of the A, B, H, Lea, and Leb substances also showed I activity comparable to the milk material. Strong I activity could be produced by one-stage periodate oxidation and Smith degradation of human ovarian cyst A and B substances, or of hog mucin A + H substance, or by mild acid hydrolysis of human saliva or ovarian cyst blood group B substance. The two sera indicate that I specificity appears at intermediate stages in the biosynthesis of the A, B, H, Lea, and Lea substances. Anti-I sera differ strikingly in their specificities, indicating substantial heterogeneity of the I determinants.

The Synthesis of Trisubstituted Enol Ethers and of Methyl Ketones from Ketones

1973 ◽  
Vol 51 (6) ◽  
pp. 981-983 ◽  
Author(s):  
Gilles Caron ◽  
Jean Lessard
Keyword(s):  
Acid Hydrolysis ◽  
Hydroxy Acid ◽  
Reliable Method ◽  
Acid Salt ◽  
Methyl Ketones ◽  
Enol Ether ◽  
Mild Acid Hydrolysis ◽  
Enol Ethers ◽  
Hydrolysis Of ◽  
Mild Acid

A reliable method for the synthesis of trisubstituted enol ethers (and of the corresponding methyl ketones) is described involving the condensation of the α-lithiated 2-methoxypropionic acid salt with a ketone to give a β-hydroxy acid, the cyclization to a β-lactone which is then decarboxylated (and mild acid hydrolysis of the enol ether).

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