Fructofuranoside

Fischer projection, monosaccharides acyclic form, 56-57 cyclic forms, 59-60 modified, 60-61 Fluorine chemistry, 18-19 D-Fructofuranosides, degradation, 445 Fructofuranosyl cation, 217 Fructofuranosyl fluorides, 217 Fructose... 

Methyl-D-fructofuranosides, 445 -447 4-Methyl-5-(2-hydroxyethyl)thiazole, 268-269 O-Methylsucroses, degradation, 447 Methyl trifiate, 187... 

Deoxy-4-fluoro- a/flc/o-sucrose (617 4-deoxy-4-fluoro-a-D-galacto-pyranosyl D-fructofuranoside), 2,3,1, 3, 4, 6 -hexa-0-benzyl-4,6-dideoxy-4,6-difluorosucrose (618), 2,3,1, 3, 4, 6 -hexa-0-benzyl-6-deoxy-6-... 

Ci2H22Ou / -d-Fructofuranosyl a-D-glucopyranoside a-D-glucopyranosyl / -D-fructofuranoside (sucrose) SUCROS, 02, 03, 04, 11 31 352... 

Ci8H32016 5 H20 0-a-D-Galactopyranosyl-(l- 6)-0-a-D-glucopyranosyl /J-D-fructofuranoside, pentahydrate (raffinose, pentahydrate) RAFINO 30 455... 

C24H42021-4.4 H20 0-a-Galactopyranosyl-( 1 — 6)-0-a-D-galactopyranosyl-( 1 — 6)-O-a-D-fucopyranosyl /J-D-fructofuranoside, hydrate (stachyose, hydrate) STACHY 34 372... 

However, some carbohydrates with a terminal D-fructofuranose residue are not suitable substrates for levan formation, e. g., methyl /3-d-fructofuranoside and inulin,64 even in the presence of enzymes98 which hydrolyze these substrates. 

The specificity of levansucrase98 is dependent not only on the d-fructoside but also on the aldoside residue of the substrate. Neither inulin nor methyl D-fructofuranoside was hydrolyzed by levansucrase, and even when these two substrates were hydrolyzed by inulase (prepared from inulin-fermenting Torula yeast) or by yeast invertase respectively, no levan formation occurred with levansucrase. However, neither methyl D-fructofuranoside nor inulin inhibited levan formation from sucrose by levansucrase. No levan was formed from potassium D-glucose... 

Lespieau, R., Synthesis of Hexitols and Pentitols from Unsaturated Poly-hydric Alcohols, II, 107-118 Levi, Irving, and Purves, Clifford B., The Structure and Configuration of Sucrose (oipta-D-Glucopyranosyl beta-D-Fructofuranoside), IV, 1-35 Liggett, R. W., and Deitz, Victor R., Color and Turbidity of Sugar Products, IX, 247-284... 

The synthesis of (3-D-fructofuranosides is yet another useful application of this concept [293-295]. The latter 1,2-cis-glycosidic linkage is as difficult to establish as in the case of (3-mannosides. In an elegant synthesis of a-D-fucofuranose-containing disaccharides, Plusquellec and coworkers used the IAD concept via p-methoxybenzylidene acetals in combination with a glycosylation protocol via pentenyl glycosides. Here, the intermediate NIS-adduct could be isolated (Scheme 5.108) [295]. 

There is also strong evidence for the type of glycosidic linkage existing in the fructose constituent of the sucrose molecule. Schlubach and Rauchalles18 showed that invertase hydrolyzes sucrose and methyl /3-D-fructofuranoside at approximately the same rate, indicating that... 

Valuable information regarding the specificity requirements of enzymes acting on carbohydrates may be expected from a discussion of fructofuranosides as substrates for enzyme action. Not only is the hydrolysis of sucrose by /3-fructofuranosidase (saccharase, invertase) one... 

The same holds for substitution at C3 and C5 of the fructofuranose moiety of sucrose neither melezitose (XV)61 nor o-D-glucopyranosyl-/3-D-xyloketofuranoside (XVIc)22 is hydrolyzed by yeast saccharase. As might have been expected from the experience with glycosidases, any change in the configuration of the fructon of sucrose results in stereoisomers unhydrolyzable by /3-fructofuranosidase. Thus, methyl and benzyl a-D-fructofuranosides,62 isosucrose (= /3-D-glucopyranosyl-a-D-fructo-... 

Though there is no direct evidence that the D-fructofuranose unit in melezitose is of -configuration, the facts that all naturally occurring fructofuranoside sugars known so far are sucrose or sucrose derivatives and that the equilibrium mixture of D-fructose appears to consist almost entirely of /3-o-fructopyranose and /3-D-fructo-furanose, are very suggestive of a /3-configuration. For a full discussion of the problem see C. S. Hudson, Advances in Carbohydrate Chem., II, 1 (1946). 

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