14274-90-9Relevant articles and documents
Cycloheptaamylose as a model for starch in the pyrolysis of polysaccharides
Lowary,Richards
, p. 157 - 166 (2007/10/02)
The pyrolysis of cycloheptaamylose has been studied as a model for starch. 1,6-Anhydro-β-D-glucopyranose (levoglucosan, LG, 7) and its furanose isomer are major products from vacuum pyrolysis at 280, 300, and 320°, with combined yields ranging from 38 to 50% of the substrate-dependent on temperature. Pyrolysis in methyl sulfoxide at 150° produced LG and glucose as well as gluco-oligosaccharides of d.p. up to 7, with both reducing and 1,6-anhydro end-groups. A mechanism is postulated in which the first step is the heterolytic scission of a glucosidic linkage to form a linear, seven-membered oligosaccharide having a glucosyl cation in place of the reducing end-group. The cation is stabilized either by intramolecular attack of O-6 on the C-1 cation or by intermolecular transglycosylation. The former product subsequently yields LG upon scission of a terminal glucosidic linkage. The pyrolysis of cycloheptaamylose has been studied as a model for starch. 1,6-Anhydro-β-D-glucopyranose (levoglucosan, LG, 7) and its furanose isomer are major products from vacuum pyrolysis at 280, 300, and 320°, with combined yields ranging from 38 to 50% of the substrate dependent on temperature. Pyrolysis in methyl sulfoxide at 150° produced LG and glucose as well as gluco-oligosaccharides of d.p. up to 7, with both reducing and 1,6-anhydro end-groups. A mechanism is postulated in which the first step is the heterolytic scission of a glucosidic linkage to form a linear, seven-membered oligosaccharide having a glucosyl cation in place of the reducing end-group. The cation is stabilized either by intramolecular attack of O-6 on the C-1 cation or by intermolecular transglycosylation. The former product subsequently yields LG upon scission of a terminal glucosidic linkage.
O-BENZYL PROTECTING GROUPS AS HYDROGEN DONORS IN CATALYTIC TRANSFER HYDROGENOLYSIS. SELECTIVE DEBENZYLATION OF 1,6-ANHYDRO HEXOSES.
Cruzado, Carmen M. del,Martin-Lomas, Manuel
, p. 2497 - 2500 (2007/10/02)
O-benzyl protecting groups may act as hydrogen donors in heterogenous catalytic transfer hydrogenolysis.Hydrogenolysis of compunds 1 - 4 demonstrated that this hydrogen transfer occurs adjacent cis-disposed hydroxyl groups are present.