"Complexes of carbohydrates with magnesium-ions" : "the isolation of an oligosaccharide containing L-galactose from the polysaccharide of Aeodes orbitosa" : "horizontal cellulose colum chromatography of sugars"
- Authors: Van der Linde, Michael John
- Date: 1974
- Subjects: Magenesium , Ions , Carbohydrates , Oligosaccharides , Polysaccharides , Chromatographic analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4504 , http://hdl.handle.net/10962/d1013282
- Description: Sugar complexes with anions and cations are reviewed. Evidence is presented for the formation of a complex of stoichiometry 1:1 in aqueous solution between methyl-α-Dglucopyranoside and magnesium perchlorate. The complex may be detected by the method of continuous variations. Measurements of changes in the proton chemical shifts of the glucoside in dauterium oxide, indicate that the complex is probably formed between the vicinal hydroxyl groups at C-2 and C-3 of the pyranoside ring and the hydrated cation. At elevation temperatures there is evidence for the presence of a complex of stoichiometry 2:1. Experiments conducted on cellulose indicate the possible formation of cellulose - magnesium-ion complexes . These complexes provide an explanation for the "protective action" of mEgnesium compounds on the cellulose portion of pulp during alkali-oxygen bleaching.
- Full Text:
- Date Issued: 1974
- Authors: Van der Linde, Michael John
- Date: 1974
- Subjects: Magenesium , Ions , Carbohydrates , Oligosaccharides , Polysaccharides , Chromatographic analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4504 , http://hdl.handle.net/10962/d1013282
- Description: Sugar complexes with anions and cations are reviewed. Evidence is presented for the formation of a complex of stoichiometry 1:1 in aqueous solution between methyl-α-Dglucopyranoside and magnesium perchlorate. The complex may be detected by the method of continuous variations. Measurements of changes in the proton chemical shifts of the glucoside in dauterium oxide, indicate that the complex is probably formed between the vicinal hydroxyl groups at C-2 and C-3 of the pyranoside ring and the hydrated cation. At elevation temperatures there is evidence for the presence of a complex of stoichiometry 2:1. Experiments conducted on cellulose indicate the possible formation of cellulose - magnesium-ion complexes . These complexes provide an explanation for the "protective action" of mEgnesium compounds on the cellulose portion of pulp during alkali-oxygen bleaching.
- Full Text:
- Date Issued: 1974
A structural investigation of the sulphated polysaccharide of Anathaca dentata (suhr) papenf. and the xylan of Chaetangium erinaceum (turn.) papenf.
- Authors: Russell, Irina
- Date: 1972
- Subjects: Polysaccharides , Marine algae -- Composition
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4494 , http://hdl.handle.net/10962/d1013103
- Description: Hot-water extraction of Anatheca dentata, a red seaweed belonging to the family Solieriaceae, yielded a mixture of polysaccharides. Fractionation of this mixture with Cetavlon gave a glucomannan as minor component and a highly sulphated major component, which gave D- and L-galactose, D-xylose and small amounts of 3-0 (underscore)-methylgalactose, pyruvic acid and uronic acid on hydrolysis. All subsequent investigations were carried out on the sulphated major component. The sulphate was not labile to alkali, but was removed with methanolic hydrogen chloride. Periodate oxidation of the polysaccharide before and after desulphation indicated that new a-glycol groups were formed during desulphation. All the xylose units in the polymer were cleaved by periodate and this, together with the fact that the major xylose product from methylation analysis of the desulphated polymer was the 2,3, 4-tri-0 (underscore)-methyl derivative, indicated that the xylose occurs as a non-reducing end-group. Methylation of the desulphated polysaccharide revealed the presence of 1,4- and 1,3- linked D- galactose and 1,4- linked L-galactose units in the polymer. D-Glucuronic acid occurred as non-reducing end-groups. Summary, p. 1.
- Full Text:
- Date Issued: 1972
- Authors: Russell, Irina
- Date: 1972
- Subjects: Polysaccharides , Marine algae -- Composition
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4494 , http://hdl.handle.net/10962/d1013103
- Description: Hot-water extraction of Anatheca dentata, a red seaweed belonging to the family Solieriaceae, yielded a mixture of polysaccharides. Fractionation of this mixture with Cetavlon gave a glucomannan as minor component and a highly sulphated major component, which gave D- and L-galactose, D-xylose and small amounts of 3-0 (underscore)-methylgalactose, pyruvic acid and uronic acid on hydrolysis. All subsequent investigations were carried out on the sulphated major component. The sulphate was not labile to alkali, but was removed with methanolic hydrogen chloride. Periodate oxidation of the polysaccharide before and after desulphation indicated that new a-glycol groups were formed during desulphation. All the xylose units in the polymer were cleaved by periodate and this, together with the fact that the major xylose product from methylation analysis of the desulphated polymer was the 2,3, 4-tri-0 (underscore)-methyl derivative, indicated that the xylose occurs as a non-reducing end-group. Methylation of the desulphated polysaccharide revealed the presence of 1,4- and 1,3- linked D- galactose and 1,4- linked L-galactose units in the polymer. D-Glucuronic acid occurred as non-reducing end-groups. Summary, p. 1.
- Full Text:
- Date Issued: 1972
A structural investigation of the sulphated polysaccharides of Aeodes orbitosa and Phyllymenia cornea
- Authors: Parolis, Haralambos
- Date: 1968
- Subjects: Polysaccharides , Marine algae -- Composition
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4487 , http://hdl.handle.net/10962/d1012999
- Description: A highly sulphated, methylated polysaccharide, aeodan, isolated from the red seaweed Aeodes orbitosa was shown to contain galactose, 2-̲̲O-methyl-D-galactose, 4-O̲-methyl-Lgalactose, 6-O̲-methyl-D-galactose, xylose, and glycerol. The polysaccharide was desulphated with methanolic hydrogen chloride. Periodate oxidation of aeodan and desulphated aeodan, followed by reduction and hydrolysis, revealed the presence of 1,4- and 1,3-linked galactose residues and 1,3-linked 6-O̲-methy l-D-galactose residues in aeodan. Treatment of aeodan with sodium hydroxide revealed that the majority of the ester sulphate groups were alkali stable. Methylation of desulphated aeodan revealed that the polysaccharide was composed entirely of 1,3 and 1,4 links. Methylation of aeodan revealed the presence of 1,3- and 1,4- linked units, 1,3-linked galactose-2-sulphate, and 1,3-linked galactose-2, 6-disulphate units in the polysaccharide. Partial hydrolysis of aeodan resulted in the isolation and characterisation of 3-O̲-D-galactopyranosyl-D-galactose and 4-O̲-ß-D-galactopyranosyl- D-galactose. A sulphated, methylated polysaccharide, phyllymenan, isolated from the red seaweed Phyllymenia cornea was shown to contain galactose, 2-O̲-methyl-D-galactose, 4-O̲-methyl L- galactose , 6-O̲-methyl -D-galactose, and xylose. The polysaccharide was completely desulphated with methanolic hydrogen chloride. Periodate oxidation of phyllymenan before and after desulphation revealed that removal of the sulphate ester groups had not produced any new adjacent hydroxyl groups. Alkali treatment of phyllymenan revealed that the ester sulphate groups were alkali stable. Methylation studies on phyllymenan revealed the presence of 1,3- and 1,4-linked units, 1,3-linked galactose-2-sulphate, and 1,3-linked galactose- 2,6-disulphate units in the polysaccharide. Partial hydrolysis of phyllymenan revealed the presence or 4-O-̲ß- D-Dgalactopyranosyl- D-galactosc, 4-O-̲ß-D-galactopyranosyl -2-0- methyl-D-galactose, a galactosylgalactose composed of D and L-galactose, and adjacent 6-O̲-methyl- and 2-O̲-methyl-D- galactose units in the polysaccharide.
- Full Text:
- Date Issued: 1968
- Authors: Parolis, Haralambos
- Date: 1968
- Subjects: Polysaccharides , Marine algae -- Composition
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4487 , http://hdl.handle.net/10962/d1012999
- Description: A highly sulphated, methylated polysaccharide, aeodan, isolated from the red seaweed Aeodes orbitosa was shown to contain galactose, 2-̲̲O-methyl-D-galactose, 4-O̲-methyl-Lgalactose, 6-O̲-methyl-D-galactose, xylose, and glycerol. The polysaccharide was desulphated with methanolic hydrogen chloride. Periodate oxidation of aeodan and desulphated aeodan, followed by reduction and hydrolysis, revealed the presence of 1,4- and 1,3-linked galactose residues and 1,3-linked 6-O̲-methy l-D-galactose residues in aeodan. Treatment of aeodan with sodium hydroxide revealed that the majority of the ester sulphate groups were alkali stable. Methylation of desulphated aeodan revealed that the polysaccharide was composed entirely of 1,3 and 1,4 links. Methylation of aeodan revealed the presence of 1,3- and 1,4- linked units, 1,3-linked galactose-2-sulphate, and 1,3-linked galactose-2, 6-disulphate units in the polysaccharide. Partial hydrolysis of aeodan resulted in the isolation and characterisation of 3-O̲-D-galactopyranosyl-D-galactose and 4-O̲-ß-D-galactopyranosyl- D-galactose. A sulphated, methylated polysaccharide, phyllymenan, isolated from the red seaweed Phyllymenia cornea was shown to contain galactose, 2-O̲-methyl-D-galactose, 4-O̲-methyl L- galactose , 6-O̲-methyl -D-galactose, and xylose. The polysaccharide was completely desulphated with methanolic hydrogen chloride. Periodate oxidation of phyllymenan before and after desulphation revealed that removal of the sulphate ester groups had not produced any new adjacent hydroxyl groups. Alkali treatment of phyllymenan revealed that the ester sulphate groups were alkali stable. Methylation studies on phyllymenan revealed the presence of 1,3- and 1,4-linked units, 1,3-linked galactose-2-sulphate, and 1,3-linked galactose- 2,6-disulphate units in the polysaccharide. Partial hydrolysis of phyllymenan revealed the presence or 4-O-̲ß- D-Dgalactopyranosyl- D-galactosc, 4-O-̲ß-D-galactopyranosyl -2-0- methyl-D-galactose, a galactosylgalactose composed of D and L-galactose, and adjacent 6-O̲-methyl- and 2-O̲-methyl-D- galactose units in the polysaccharide.
- Full Text:
- Date Issued: 1968
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