Fructofuranosides ethyl

Weidenhagen6 found no hydrolysis of either methyl or phenyl /3-D-fructofuranoside by /3-D-fructofuranosidase ( of Saccharomyces cerevisiae) but Purves and Hudson,66 like Schlubach and Rauchalles,67 reported that this enzyme, presumed by Gottschalk68 to be from yeast, hydrolyzed methyl /3-D-fructofuranoside, although only 7% as fast as for sucrose. Purified /3-D-fructofuranosidase of Saccharomyces cerevisiae hydrolyzed ethyl /3-D-fructofuranoside and N-p-nitrophenyl-/3-D-fructofuranosylamine according to Baseer and Shall,68 who suggested... 

Treatment of either anomer of fructose with excess ethanol in the presence of a trace of HC1 gives a mixture of the a and /3 anomers of ethyl-D-fructofuranoside. Draw the starting materials, reagents, and products for this reaction. Circle the aglycone in each product. 

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). 

Perlin, but a definite structure was not given. During the same work, both anomers of ethyl n-fructofuranoside were treated with chlorotriphenyl-methane. Only the /J-d anomer gave a crystalline 1,6-di-O-trityl derivative. The positions of the ether groups were determined by periodic acid oxidation, and, in both cases, one mole was consumed per mole. 

Attempts to overcome this obstacle have included the use of ethyl 1,3,4,6-tetra-O-benzyl-2-thio-D-fructofuranoside as the glycosyl donor, and use of thiophilic promoters. Predictably, a,(3 mixtures were obtained, with the a anomers predominating. 

Transesterification of 2-O-dodecyl a-D-fructofuranoside (21) with ethyl decanoate and SP 435 lipase gave initially the 6-mono-ester 22 which was slowly converted into di-esters, mainly the 1,6-di-ester 23. Addition of zeolite CaA allowed selective formation of either 22 or 23, depending on the reaction time. 

Substituted 5-ethyl 1-thio-P-D-fructofuranoside derivatives activated with IDCP led predominantly to a-linked disaccharides, the 6-substituted galactose being produced in high yield with exclusively a-linking. ... 

Two polymorphs of a,a-trehalose octacetate monohydrate, 4,4 -dideoxy-a,a- ty/o-trehalose, methyl 2,3,4,6,2, 4, 6 -hepta-C -acetyl-a-laminaribinoside, 2 3,3 -dideoxy-a,a-flrflbjno-trehalosc. 3 Methyl 2,3-0-isopropylidene-5-0-tosyl-P-D-ribofuranoside 2, the 7-carbon glycoside 3 (see Chapter 17), C-glycosidic furanoside 4 (see Chapter 14) the oxazoline derivative 5 and methyl 1,6-di-0-(4-bromobenzoyl)-3,4-di-0-(4-methoxycinnamoyl)-P-D-fructofuranoside. Di-(3-deoxy-D-g/yccro-pcntulose)-l,2 2,r-dianhydridc, methyl 4,6-benzylidene-a-D-allopyranoside, methyl-2,3,4-tri-0-acctyl-a-L-rhamnopyranoside, l 2-(indol-3-yl)ethyl 2,3,4-tri-O-acetyl-a-L-... 

Building on their work reported since 1996 describing investigations on the use of some sugars, notably fructosides, in reduction, epoxida-tion, and indium-promoted allylations, Plusquellec and coworkers recently reported the use of IM sucrose or ethyl fructofuranoside as additives in the aqueous aldolisation reaction of methyl 4-methylcyclo-hexanone with m-nitrophenylbenzaldehyde (and diversely functionalized analogues) performed in the presence of organocatalysts such as L-pro-line (Scheme 8, Table 6). Significant variations in the anti-syn selectivity were observed. 

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