SELECTIVE SUBSTITUTION IN SUCROSE: I. THE SYNTHESIS OF 1′,4,6′-TRI-O-METHYL SUCROSE

1957 ◽  
Vol 35 (1) ◽  
pp. 30-38 ◽  
Author(s):  
G. G. McKeown ◽  
R. S. E. Serenius ◽  
L. D. Hayward
Keyword(s):  
Acetic Acid ◽  
Periodate Oxidation ◽  
Selective Substitution ◽  
Acetyl Group ◽  
Group Migration

Sucrose was tritylated and acetylated to give a crystalline tri-O-trityl-penta-O-acetyl sucrose derivative, and detritylation of this product by graded hydrolysis with acetic acid followed by methylation and deacetylation yielded 1′,4,6′-tri-O-methyl sucrose. The structure of the tri-O-methyl sucrose was established by periodate oxidation and by hydrolysis to the corresponding O-methyl ethers of glucose and fructose. Acetyl group migration from C4 to C6 in the glucose moiety of sucrose probably occurred during the methylation reaction.Some aspects of syntheses involving sucrose are discussed.

scholarly journals Kinetic Studies of Acetyl Group Migration between the Saccharide Units in an Oligomannoside Trisaccharide Model Compound and a Native Galactoglucomannan Polysaccharide

ChemBioChem ◽  
2021 ◽  
Author(s):  
Robert Lassfolk ◽  
Sara Bertuzzi ◽  
Ana Ardá ◽  
Johan Wärnå ◽  
Jesús Jiménez‐Barbero ◽  
...  
Keyword(s):  
Model Compound ◽  
Kinetic Studies ◽  
Acetyl Group ◽  
Group Migration

On the basic structure of poly (glycerophosphate) lipoteichoic acids

1990 ◽  
Vol 68 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Werner Fischer ◽  
Tibor Mannsfeld ◽  
Gerhard Hagen
Keyword(s):  
Acetic Acid ◽  
Periodate Oxidation ◽  
Hydrophobic Interaction Chromatography ◽  
Basic Structure ◽  
Bacterial Membrane ◽  
Gram Positive ◽  
Molar Ratios ◽  
Gram Positive Bacteria ◽  
Oral Group ◽  
Lipoteichoic Acids

Poly(glycerophosphate) lipoteichoic acids from 24 Gram-positive bacteria of the genera Bacillus, Enterococcus, Lactobacillus, Lactococcus, Listeria, Staphylococcus, and the streptococcal pyogenic and oral group were analyzed. The 1,3-linked poly(glycerophosphate) structure was proved by analysis of glycerol and glycerophosphates after acid and alkaline hydrolysis. Using the molar ratios of glycolipid to phosphorus (A) and phosphomonoester to phosphorus after periodate oxidation followed by hydrazinolysis (B) or β-elimination (C), we show that all lipoteichoic acids contain a single unbranched poly(glycerophosphate) chain and that the chain is uniformly phosphodiester-linked to C-6 of the nonreducing hexopyranosyl residue of the glycolipid moiety. On some chains minor phosphate-containing substituents were detected whose structure remains to be clarified. The lipoteichoic acids of enterococci and listeria strains were separated by hydrophobic interaction chromatography into glycolipid- and phosphatidylglycolipid-containing molecular species. The phosphatidylglycolipid moieties were structurally characterized after liberation from lipoteichoic acids with moist acetic acid. After periodate oxidation of lipoteichoic acids β-elimination released both phosphatidic acid and the poly(glycerophosphate) chain. This indicates together with the sequence analysis of the released phosphatidylglycolipid that the phosphatidyl residue is located at C-6 of the reducing hexosyl residue of the glycolipid moiety and the poly(glycerophosphate) chain at C-6 of the nonreducing one. Together with earlier observations these results complete the evidence for the structural and possibly biosynthetic relationship between lipoteichoic acids and glycerophosphoglycolipids.Key words: lipoteichoic acids, poly(glycerophosphate) lipoteichoic acids, Gram-positive bacteria, bacterial membrane.

scholarly journals Acetyl Group Migration across the Saccharide Units in Oligomannoside Model Compound

2018 ◽  
Vol 141 (4) ◽  
pp. 1646-1654 ◽  
Author(s):  
Robert Lassfolk ◽  
Jani Rahkila ◽  
Mikael P. Johansson ◽  
Filip S. Ekholm ◽  
Johan Wärnå ◽  
...  
Keyword(s):  
Model Compound ◽  
Acetyl Group ◽  
Group Migration

4,6-O-(1-Carboxyethylidene)-D-mannose as a Structural Unit in Capsular Polysaccharide of Klebsiella K-type 5

1972 ◽  
Vol 50 (14) ◽  
pp. 2382-2384 ◽  
Author(s):  
G. G. S. Dutton ◽  
M. T. Yang
Keyword(s):  
Experimental Data ◽  
Structural Unit ◽  
Capsular Polysaccharide ◽  
Periodate Oxidation ◽  
Side Chain ◽  
Partial Hydrolysis ◽  
Acetyl Group

Methylation, periodate oxidation, and partial hydrolysis techniques have each been used to demonstrate the presence of 4,6-O-(1-carboxyethylidene)-D-mannopyranosyl units in the capsular polysaccharide of Klebsiella K-type 5. The structure of this polysaccharide differs from those known for other Klebsiella capsules by the lack of any carbohydrate side chain. A repeating unit of[Formula: see text](plus one unassigned O-acetyl group) is in accord with the experimental data.

Structure of the Capsular Polysaccharide of Klebsiella K-type 20

1973 ◽  
Vol 51 (18) ◽  
pp. 3015-3020 ◽  
Author(s):  
Yuen-Min Choy ◽  
Guy G. S. Dutton
Keyword(s):  
Capsular Polysaccharide ◽  
Periodate Oxidation ◽  
Partial Hydrolysis ◽  
Acetyl Group ◽  
Unit Formula

Methylation, periodate oxidation, and partial hydrolysis studies on the capsular polysaccharide, and on the carboxyl reduced polymer, of Klebsiella K20 show the structure to consist of a repeating unit[Formula: see text]The anomeric linkages were determined by p.m.r. spectroscopy of the carboxyl reduced polysaccharide, and periodate degraded polysaccharides. The p.m.r. spectroscopy of the original polysaccharide also showed the presence in the polysaccharide of one O-acetyl group per eight sugar residues.

Structural analysis of the three lipopolysaccharides produced by Salmonella madelia (1,6,14,25)

1989 ◽  
Vol 67 (2-3) ◽  
pp. 78-85 ◽  
Author(s):  
José L. Di Fabio ◽  
Jean-Robert Brisson ◽  
Malcolm B. Perry
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Acetic Acid ◽  
Magnetic Resonance ◽  
Nitrous Acid ◽  
Periodate Oxidation ◽  
Ps Ii ◽  
Polysaccharide Fraction ◽  
Ps I ◽  
Hydrolysis Of ◽  
Nuclear Magnetic

Salmonella madelia reported to express the O-antigenic factors 1, 6, 14, and 25, defined in the Kauffmann–White classification system, was found to produce three different homogeneous lipopolysaccharides, which differed in having three structurally distinct O-polysaccharide components. The O-polysaccharide fraction obtained by mild acetic acid hydrolysis of the S. madelia lipopolysaccharide was analyzed by chemical composition, nitrous acid deamination, periodate oxidation, methylation, and 1H and 13C nuclear magnetic resonance methods and was demonstrated to be composed of three polysaccharides, PS(I), PS(II), and PS(III), which had the structures of repeating oligosaccharide units:[Formula: see text]Key words: Salmonella madelia, lipopolysaccharide, structure, analysis, nuclear magnetic resonance.

Nitration of 4-tert-butyl-o-xylene in acetic anhydride. Formation and rearomatization of adducts

1978 ◽  
Vol 56 (2) ◽  
pp. 258-266 ◽  
Author(s):  
Alfred Fischer ◽  
Khay Chuan Teo
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Nitro Group ◽  
Tert Butyl ◽  
Acidic Conditions ◽  
Group Migration

Nitration of 4-tert-butyl-1,2-dimethylbenzene in acetic anhydride gives trans-1-tert-butyl-3,4-dimethyl-4-nitro-1,4-dihydrophenyl acetate (6), trans-1-tert-butyl-3,4-dimethyl-4-nitro-1,4-dihydrophenol, 2-tert-butyl-4,5-dimethylphenyl acetate, 5-tert-butyl-2-methylbenzaldehyde, 4-tert-buty]-1,2-dimethyl-5-nitrobenzene, and 4-tert-butyl-1,2-dimethyl-6-nitrobenzene. 2-tert-Butyl-4,5-dimethylphenyl acetate and 3,4-dimethylphenyl acetate are the major products of solvolysis of 6 in moist acetic acid. Both of these compounds are likely formed via the cation generated by ionization of the nitro group. Under more acidic conditions 5-tert-butyl-2-methylbenzaldehyde and 4-tert-butyl-1,2-dimethyl-6-nitrobenzene, formed via the cation generated by acid-catalysed loss of acetate, become dominant, the balance between these products being controlled by the basicity of the solvent. More basic solvents deprotonate the cation to a triene, a key step in the formation of the aldehyde, at a competitive rate with the nitro group migration.

scholarly journals Zwitterionic Acetylated Cellulose Nanofibrils

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3147 ◽  
Author(s):  
Jowan Rostami ◽  
Aji P. Mathew ◽  
Ulrica Edlund
Keyword(s):  
Acetic Acid ◽  
Schiff Base ◽  
Reaction Time ◽  
Structural Changes ◽  
Glacial Acetic Acid ◽  
Cellulose Nanofibrils ◽  
Periodate Oxidation ◽  
Hydroxyl Groups ◽  
Borohydride Reduction ◽  
Short Reaction Time

A strategy is devised to synthesize zwitterionic acetylated cellulose nanofibrils (CNF). The strategy included acetylation, periodate oxidation, Schiff base reaction, borohydride reduction, and a quaternary ammonium reaction. Acetylation was performed in glacial acetic acid with a short reaction time of 90 min, yielding, on average, mono-acetylated CNF with hydroxyl groups available for further modification. The products from each step were characterized by FTIR spectroscopy, ζ-potential, SEM-EDS, AFM, and titration to track and verify the structural changes along the sequential modification route.

SELECTIVE SUBSTITUTION IN SUCROSE: II. THE SYNTHESIS OF 2,3,3′,4,4′-PENTA-O-METHYL SUCROSE AND C4 TO C6 ACETYL MIGRATION IN SUCROSE

1957 ◽  
Vol 35 (9) ◽  
pp. 992-997 ◽  
Author(s):  
G. G. McKeown ◽  
L. D. Hayward
Keyword(s):  
Acetic Acid ◽  
Transition State ◽  
Acyl Migration ◽  
Hydrolytic Cleavage ◽  
Selective Substitution ◽  
Acetyl Migration

Deacetylation of crystalline tri-O-trityl-penta-O-acetyl sucrose gave an amorphous tri-O-trityl sucrose derivative and methylation of this product followed by graded hydrolysis with acetic acid yielded a sirupy penta-O-methyl sucrose. Hydrolytic cleavage of the penta-O-methyl sucrose to nearly equal amounts of 2,3,4-tri-O-methyl-D-glucose and 3,4-di-O-methyl-D-fructose established the original positions of the O-trityl groups at the primary carbons in the sucrose molecule. It was therefore evident that acetyl migration from C4 to C6 in the glucose moiety had occurred during an earlier synthesis of 1′,4,6′-tri-O-methyl sucrose from the tri-O-trityl-penta-O-acetyl sucrose. The probable conformation of the transition state in the acyl migration is discussed.

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