- Phosphorylase-catalyzed N-formyl-α-glucosaminylation of maltooligosaccharides
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This paper describes the phosphorylase-catalyzed enzymatic N-formyl-α-glucosaminylation of maltooligosaccharides for direct incorporation of 2-deoxy-2-formamido-α-d-glucopyranose units into maltooligosaccharides. When the reaction of 2-deoxy-2-formamido-α-d-glucopyranose-1-phosphate (GlcNF-1-P) as the glycosyl donor and maltotetraose as a glycosyl acceptor was performed in the presence of phosphorylase, the N-formyl-α-d-glucosaminylated pentasaccharide was produced, as confirmed by MALDI-TOF MS. Furthermore, the glucoamylase-catalyzed reaction of the crude products supported that the 2-deoxy-2-formamido-α-d-glucopyranoside unit was positioned at the non-reducing end of the pentasaccharide. The pentasaccharide was isolated from the crude products and its structure was further determined by the 1H NMR analysis. On the other hand, when the phosphorylase-catalyzed reactions of maltotriose and maltopentaose using GlcNF-1-P were conducted, no N-formyl-α-glucosaminylation took place in the former system, whereas the latter system gave N-formyl-α-d-glucosaminylated oligosaccharides with various degrees of polymerization. These results could be explained by the recognition behavior of phosphorylase toward maltooligosaccharides.
- Kawazoe, Satoshi,Izawa, Hironori,Nawaji, Mutsuki,Kaneko, Yoshiro,Kadokawa, Jun-ichi
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experimental part
p. 631 - 636
(2010/09/20)
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- Lipid analogs of the nodulation factors using the ugi/passerini multicomponent reactions: Preliminary studies on the carbohydrate monomer
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Treament of 1,3,4,6-tetra-O-acetyl-2-deoxy-2-isocyano-β-D-gluco-pyranose and the corresponding β-allyl glycoside with octanal and acetic acid provide the Passerini products in excellent yields whereas the corresponding Ugi transformation in the presence of i-propylamine proceeded with much lower efficiency. This work represents a preliminary investigation on a project directed towards the modification of the lipid moiety of the nodulation factors.
- Grenouillat, Nathalie,Vauzeilles, Boris,Beau, Jean-Marie
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experimental part
p. 891 - 901
(2009/09/28)
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- Reactions of Relevance to the Chemistry of Aminoglycoside Antibiotics. Part 14. A Useful Radical-deamination Reaction
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Primary, secondary, and tertiary aliphatic or alicyclic isocyanides are smoothly reduced under radical conditions using tri-n-butylstannane to the corresponding hydrocarbons.The relative ease of reduction is tertiary > secondary > primary.Aromatic isocyanides are not reduced under these conditions.The reduction of isothiocyanates (or isoselenocyanates) by tri-n-butylstannanae also affords hydrocarbons, but here the isocyanides have been shown to be intermediates.The reduction of a compound with isocyanide and xanthate functions in a 1,2-relationship gives a smooth radical fragmentation to furnish an olefin.An efficient synthesis of 2-deoxy-D-glucose starting with glucosamine is described.
- Barton, Derek H. R.,Bringmann, Gerhard,Lamotte, Genevieve,Motherwell, William B.,Motherwell, Robyn S. Hay,Porter, Alexander E. A.
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p. 2657 - 2664
(2007/10/02)
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