52049-72-6Relevant articles and documents
Synthesis of positional thiol analogs of β-D-galactopyranose
Pei, Zhichao,Dong, Hai,Caraballo, Remi,Ramstroem, Olof
, p. 4927 - 4934 (2008/03/14)
Approaches toward the synthesis of thio-β-D-galactose derivatives are described. These compounds were prepared from the parent carbohydrates: D-galactose, methyl β-D-galactoside and methyl β-D-glucoside, respectively. It was found that not only the strategies of protecting group introduction and selective deprotection, but also the choices of solvent and nucleophilic reagent concentration were crucial to allow the efficient introduction of sulfur at different positions of the galactose ring. The effects from the solvent, the nucleophilic reagent concentration, and the protecting group patterns have been investigated. The results clearly show that ester protecting groups play highly important roles for the synthesis of thio-containing carbohydrates, requiring nonpolar solvents to suppress the neighboring group participation. For the Lattrell-Dax (nitrite-mediated) inversion reaction, employed in the synthetic route to the 2-thio-β-D- galactoside, intramolecular nucleophilic attack, as well as stronger stereospecific ester activation, are necessary to overcome hindrance from 4,6-O-benzylidene protection. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Stereospecific ester activation in nitrite-mediated carbohydrate epimerization
Dong, Hai,Pei, Zhichao,Ramstroem, Olof
, p. 3306 - 3309 (2007/10/03)
The Lattrell-Dax method of nitrite-mediated substitution of carbohydrate triflates is an efficient method to generate structures of inverse configuration. In the present study, epimerization of gluco- and galactopyranoside derivatives to the corresponding
NOVEL D-GLUCANS OBTAINED BY DIMETHYL SULFOXIDE EXTRACTION OF THE LICHENS Letharia vulpina, Actinogyra muehlenbergii, AND AN Usnea SP.
Iacomini, Marcello,Gorin, Philip A. J.,Baron, Madalena,Tulloch, Alexander P.,Mazurek, Mytosk
, p. 117 - 126 (2007/10/02)
Extraction of certain lichens with cold dimethyl sulfoxide provided a β-D-glucan virtually free of contaminating α-D-glucan and galactomannan.Applied to Letharia vulpina, the method gave β-D-glucan, and extraction of the residue with hot water followed by cooling gave α-D-glucan.From Usnea sp. a β-D-glucan was isolated, but little α-D-glucan was present.Extraction of Actinogyra muehlenbergii provided a (16)-linked β-D-glucopyranan containing one acetyl group of every 8-9 glucosyl units, being present almost exclusively as monosubstituent at O-2, O-3, and O-4.