Fructofuranoside, methyl 0 anomer

For ethyl D-fructofuranoside, both anomers are formed in small proportion during the hydrogenolysis of sucrose in ethanol. When the reaction was performed at 100° in an atmosphere of argon, considerable quantities were obtained. Ethyl S-D-fructofuranoside, [ ]d —36° (in water), is readily hydrolyzed to D-fructose by invertase (and also by 0.1 N sulfuric acid) at room temperature. The same behavior was observed for a substance isolated from wheat germ. Acetylation yielded a sirupy product, but treatment with trityl chloride gave crystalline methyl 1,6-di-O-trityl-D-fructoside (m.p. 180-183°). With p-toluenesulfonyl chloride, a crystalline product is obtained, with m.p. 125-127°. Ethyl a-D-fructofuranoside ([ ]d +65°, in water) is not attacked by invertase. Tritylation, followed by acetylation, gives ethyl 3,4-di-O-acetyl-l, 6-di-O-trityl-ai-D-fructofuran-oside m.p., 142-144° and [q ]d +44.5° (in chloroform). 

In the case of the methyl D-fructofuranosides, there is a relationship to the D-arabinofuranosides, with a different type of C-l, C-2 interaction. Here, the hydrogen atom on C-l has been replaced by a hydroxymethyl group, and the difference in the C-2 interactions with the C-3 hydroxyl group should be small for the anomers the effect of the aglycon group (OMe) and the hydroxymethyl group will probably be similar. 

For the D-fructofuranosides, there is apparently little difference between interactions of either the aglycon methyl group or the hydroxymethyl group (on C-2) with the C-3 hydroxyl group the anomers are formed in approximately equal yields. The high yields obtained indicate the conformational stability of the D-fructofuranoside structure, which is very similar to that of the D-arabinofuranosides. 

Both 2,5-anhydro-D-mannitol and 2,5-anhydro-D-glucitol contain the requisite 1,4-anhydro-D-arabinitol ring system.215-240 The D-mannitol derivative is about 3.5 times as potent an inhibitor as the D-glucitol derivative, perhaps by virtue of the fact that it may bind to con A either through the hydroxyl groups at C-l, C-3, and C-4, or C-3, C-4, and C-6 (compare Ref. 429). Finally, the important observation that methyl a-and /3-D-fructofuranoside are inhibitors (the (3 anomer being approximately three times as active as the a anomer) provides an explanation for the interaction of con A with plant and bacterial levans120-215-364 (see Section II,l,h). 

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