Maltose, heptaacetate

Acetates and benzoates are widely used as characteristic derivatives of carbohydrates, and for the assay and protection of hydroxyl groups. Various maltose heptaacetates having a free hydroxyl group on C-l, C-2, C-3, C-6, or C-6 have been synthesized. 2,3,6,2, 3, 4, 6 -Hepta-0-acetyl-/3-maltose (17) has been prepared by hydrolysis of the corresponding glycosyl halide.57,58 The reaction conditions may not always result in the isolation of the anomerically unsubstituted acetate, as was shown by Corbett and coworkers,59 who obtained three... 

On treatment with aqueous potassium hydroxide for 40 h on a steam bath,32 phenyl /3-maltose heptaacetate (40) was converted into the 1,6-anhydride 41, isolated in 72% yield as its acetate (42). Compound 42... 

Comparison of the -n.m.r. spectrum of 3-0-(methylsulfonyl)-/3-maltose heptaacetate (31) with that of /3-maltose octaacetate showed only one divergence, —0.34 p.p.m. upfield of the H-3 resonance, indicative of the location of the methylsulfonyloxy group on C-3. A similar comparison of H-n.m.r.-spectral parameters as between methyl 4 -0-(methylsulfonyl)-/3-maltoside hexaacetate and methyl /3-maltoside heptaacetate revealed that the methylsulfonyloxy group in the former compound is located on C-4, as the H-4 resonance appeared —0.3 p.p.m. to higher field than the H-4 resonance for the heptaacetate.66 In the H-n.m.r. spectrum of methyl 3-azido-3-deoxy-/3-maltoside heptaacetate, the H-3 resonance appeared at 1.70 p.p.m. to higher field of... 

Maltose, heptaacetate, I, 81 a-Maltose, octaacetate, III, 377 -Maltose, octaacetate, III, 377 Maltose, phenylosazone, reaction with KOH, III, 40... 

Cyclomaltododecaose has been isolated in 0.01% yield from commercial cydodextrins. The p-cyclodextrin based on a-D-altrose has been produced in 73% yield from the corresponding per-2,3-anhydro-/na/ino-compound. Condensation of 1, 2, 2, 3, 3, 4, 6-hepta-O-acetyl-P-maltose and 6-(7-trityl maltose heptaacetate in the presence of tin(IV) chloride led to cydodextrins comprising anhydroglucoses linked P-1,6- and a-1,4- alternately. The products with 6-, 8- and 10-anhydroglucoses were obtained in 30%, 40% and 20%yield respectively. ... 

P-Maltose heptaacetate was synthesized using Brigl s anhydride with 1,2,3,6-tetra-O-acetyl-P-D-glucopyranoside at 90°C in benzene for 20 hr [82] (reaction 4.68). 

A remarkable inertness towards acylation is shown by the secondary hydroxyl group on C-3 in maltose, lactose, and their methyl j8-glycosides. Benzoylation of maltose with 10 molar equivalents of the acid chloride in pyridine gave122 the octabenzoate and the l,2,6,2, 3, 4, 6 -hepta-0-benzoyl derivative in the ratio of 5 6, and treatment of /3-maltose monohydrate with 8.8 molar equivalents of acetyl chloride in pyridine-toluene at 0° gave123 the 1,2,6,2, 3, 4, 6 -heptaacetate and the octaacetate in the ratio of 27 10. Under similar conditions of benzoylation, cellobiose was converted into its oc-... 

Maltose phenylosazone heptaacetate, on the other hand, yielded two isomeric maltose phenylosazone anhydrides " on deacetylation, both of which gave rise to pentaacetates like the other disaccharide anhydro-osazones, their precise structures are not known. It may be recalled that Diels and Meyer " isolated a dianhydride of maltose phenylosazone... 

Pacsu and Rich" discovered a new method, by which it was possible to obtain the new methyl maltoside heptaacetate in one step and in fairly good yield. The procedure consisted in the treatment of 9-maltose octaacetate in chloroform solution with aluminum chloride at room temperature. Freudenberg and I vers chloro-com pound was not isolated but the reaction mixture was treated with methyl alcohol in the presence of pyridine hexaacetylmaltose methyl 1,2-orthoacetate with m. p. 164 and -1-98.8 was obtained in 30% yield. Pacsu and Rich at-... 

The deacylation of the octaacetates of cellobiose, lactose, maltose and melibiose with Aspergillus niger lipase leads to the formation of the respective carbohydrate heptaacetates with a free anomeric OH-group at Cl in high yield1230, 232]. With... 

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