Galactofuranoside methyl

The separation of glycosides on a cellulose column was first applied to a mixture of pyranosides28 subsequently, separations were achieved for the methyl D-fructofuranosides and D-galactofuranosides.28 This technique was soon applied to many other mixtures it permits not only the isolation of crystalline products, but also a more quantitative evaluation of the formation of glycofuranosides.80-34... 

The data in Table VIII are presented in the order of the conformational stability observed for methyl glycosidation (see Table I on p. 99 and Table II on p. 105). In each of the three cases where data for both anomers are available, the trans-1,2 anomer is the more stable, and a lower rate-constant is observed. This is the same pattern as that observed in Table II. However the order of conformational stability given earlier is not observed here. The arabinofuranosides show the maximum stability, and the D-galactofuranosides and L-fucofuranosides, having similar conformations, show a similar stability, However, the furanosides of D-lyxose, n-mannose, and i>rhamnose show an unexpectedly high stability which is almost as great as those of the furanosides of the first-mentioned sugars. These data lead to the conclusion that the conformational stability for transition complexes... 

A series of similar changes was observed on treatment of 2-desoxy-D-galactose with ethanolic hydrogen chloride and it was possible to prepare ethyl 2-desoxy-a/8-D-galactofuranoside and ethyl 2-desoxy-aj8-D-galacto-pyranoside. Essentially similar results were observed with desoxy-pentoses, and the methyl glyco-furanosides and -pyranosides of 2-desoxy-L-ribose were prepared.141... 

The 2,3,5,6-tetramethyl-D-galactofuranose was accurately characterized in 1924-27 and was prepared by the acid hydrolysis of fully methylated a,/3 methyl D-galactofuranoside.lb... 

Fig. 4.—Separation of Fully Methylated Methyl Glycosides of Sugars Present in Maple-sap Arabinogalactan. (Key (I) methyl 2,3,4-tri-O-methyl-a-L-rhamnopyrano-side (II and III) methyl 2,3,5-tri-0-methyl-a,/3-L-arabinofuranosides (IV) methyl 2,3,4-tri-0-methyl-a,j3-L-arabinopyranosides (V) methyl 2,3,5,6-tetra-0-methyl-o,/3-D-galactofuranosides (VI) methyl 2,3,4,6-tetra-0-methyl-a,/3-D-galactopyranosides. Conditions column (4 ft. x 4 mm.) of butanediol succinate polyester on Celite (2 8 w/w) 150° 150 ml. of argon/min. /3-ionization detector.)...

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