Maltose Derivatives Research Articles

Discrimination between the 2,3- and the 2′,3′-hydroxyl groups of maltose and cellobiose through their specific protection

1,6-Anhydro-4′,6′- O-benzylidene-maltose and -cellobiose were subjected to temporary O-protection with a tetraisopropyldisiloxane-1,3-diyl group at the 2′,3′- and the 2,3-positions, giving 1,6-anhydro-4′,6′- O-benzylidene-2′,3′- O-(tetraisopropyldisiloxane- 1,3-diyl)maltose ( 15) and 1,6-anhydro-4′,6′- O-benzylidene-2,3- O-(tetraisopropyldisiloxane-1,3-diyl)cellobiose ( 19), respectively, in 60–64% yield. These were then subjected to various types of O-protection fo the hydroxyl groups remaining. Treatment of 15 and 19 with acetic anhydride or phenyl isocyanate gave the corresponding diacetyl and dicarbamoyl derivatives in high yield. Benzylation of the maltose derivative 15 was rather difficult, but was finally achieved through a phase-transfer reaction, to give the 2,3-di- O-benzyl derivative ( 18) in moderate yield. In the cellobiose series, benzylation of 19 was conducted similarly, giving 22, and also by employing a modification of the conventional procedure. The silyl groups of 18 and 22 were removed by treatment with tetrabutylammonium fluoride, to afford the corresponding diols in high yield.

ChemInform Abstract: CHEMICAL MODIFICATION OF MALTOSE. VII. SYNTHESIS OF 4‐O‐(2‐ACETAMIDO‐2‐DEOXY‐α‐D‐GLUCOPYRANOSYL)‐D‐GLUCOPYRANOSE (GLCNACα1 → 4GLC)

AbstractDie aus der geschützten Tosylmaltose (I) zugängliche Anhydrobenzylidenmultose (II) wird zur Ulose (IIIa) oxidiert, die mit NH2Ol‐Idas Oxim (IIIb) liefert.

Chemical modification of maltose. VII. Synthesis of 4-O-(2-acetamido-2-deoxy-.ALPHA.-D-glucopyranosyl)-D-glucopyranose (GlcNAc.ALPHA.1.RAR.4Glc).

1, 6-Anhydro-2, 3, 3'-tri-O-benzyl-4', 6'-O-benzylidene-β-maltose (5), a maltose derivative having only one unprotected hydroxyl group at the C-2' position, was synthesized from 1, 6-anhydro-4', 6'-O-benzylidene-2'-O-tosyl-β-maltose (2) by benzylation followed by removal of the tosyl group with base. Compound 5 was converted into the corresponding ulose (7) by dimethylsulfoxide (DMSO)-Ac2O oxidation. Treatment of 7 with hydroxylamine gave the 2'-oxime (9). Reduction of 9 with LiAlH4 in ether and subsequent N-acetylation gave protected 1, 6-anhydro-β-N-acetyl-glucosaminylglucose (12) and -mannosaminylglucose (13) in a yield ratio of ca. 6 : 1. Debenzylidenation followed by debenzylation of 12 or 13 gave 1, 6-anhydro-β-N-acetyl-glucosaminylglucose (17) or-mannosaminylglucose (19). The title sugar was obtained was white prisms by acetolysis of the 1, 6-anhydro-β-linkage of peracetylated 17, followed by de-O-acetylation.

Chemische synthese verzweigter polysaccharide, 7. Zur frage des abbaus der polysaccharid‐hauptkette bei verzweigung über glykosidische bindungen

Abstract6‐Trityl‐2,3‐dicarbanilyl and 2,3‐dicarbanilyl derivatives of amylose and cellulose have previously been used as a backbone to introduce oligosaccharide branches by (1 → 6) glycosidic bonds. Possible degradation prior and during the glycoside coupling was now followed by light scattering measurements on each step of derivatization. The results obtained with derivatives of technical and synthetic amyloses indicate that some degradation may occur in the tritylation reaction and possibly in the conversion to the 6‐trityl‐2,3‐dicarbanilate. In the following steps, e.g. detritylation and glycosidic condensation of glucose and maltose derivatives under the conditions applied, degradation appears to be almost absent. In corresponding studies with cellulose derivatives problems arise mainly in the tritylation step. The results of the light scattering and viscosity measurements are discussed with respect to the molecular conformation.

Attachment of (1→6)-linked malto-oligosaccharide side-chains to amylose and cellulose via 1,2-orthoesters

Comb-like molecules having oligomeric side-chains were prepared by condensation of peracetylated 1,2-(ethyl orthoacetate) derivatives of maltose, maltotetraose, and maltohexaose with 2,3-di- O-phenylcarbamoyl derivatives of amylose and cellulose. The distance between the maltose, maltotetraose, and maltohexaose branch-points introduced into amylose was 3–4, 10, and ∼ 17 d-glucose residues, respectively, and only slightly greater for cellulose. Thus, the branch frequency is considerably higher than that obtained previously by using the Bredereck and Helferich reactions. After saponification of the modified polysaccharides, the side chains of d.p. 4 and 6 attached to position 6 in the d-glucose residues of amylose and cellulose were easily extended by enzymic synthesis with potato phosphorylase.

Thiosugars. XVII. Syntheses of Maltose Derivatives having Sulfur Atom in the Reducing Moiety

A facile synthesis of cellobiosan hexaacetate (II) was described. Zemplen degradation of II, followed by the Koenigs-Knorr reaction was shown to yield 1, 2, 3, 2', 3', 4', 6'-hepta-Oacetyl-β-cellobiose (III) in 45% yield. Crystalline 6-methylsulfonate (IV), p-tolylsulfonate (V), and 6-deoxy-6-iodo acetate (VI) were synthesized. Starting from IV, via the crystalline ethylxanthate (VIII), 1, 6-anhydro-6-thio-β-cellobiose (6-thiocellobiosan) (XIII) and the fully acetate (XII) were synthesized. Five fully acetylated cellobiose derivatives (VII, IX, X, XI, and XIV) having sulfur atom at C1, C6, or both of the positions were also synthesized starting from octaacetyl-β-cellobiose, IV, or XII.

Copolymerization of 1,6‐anhydroglucose and 1,6‐anhydromaltose derivatives

AbstractThe copolymerization of 1,6‐anhydro‐2,3,4‐tri‐O‐(p‐methyl‐benzyl)‐β‐D‐glucopyrnose [TXGL, M1] with 1,6‐anhydro‐2,3‐di‐O‐benzyl‐4‐O‐(2,3,4,6‐tetra‐O‐benzyl‐α‐D‐glucopyranosyl)‐β‐D‐glucopyranose [HBMA, M2] has been studied as a method of producing dextrans of controlled composition with a linear backbone and randomly distributed single glucose units as side chains. Copolymers of intrinsic viscosities ranging from 0.51 to 0.05 dl/g are produced. The copolymerization appears to follow classical copolymerization theory but is affected adversely by the low reactivity of the maltose derivative. Reactivity ratios have been calculated for runs catalyzed by 10 mole‐% and 20 mole‐% phosphorus pentafluoride (PF5): r1 = 1.91 ± 0.35, r2 = 0.28 ± 0.25 and r1 = 2.21 ± 0.15, r2 = 0.21 ± 0.10, respectively.

Polymerization of a cellobiose derivative to comb-shaped oligosaccharides

The Lewis acid-catalyzed polymerization of 1,6-anhydro-2,3-di- O-benzyl-4- O-(2,3,4,6-tetra- O-benzyl-β- d-glucopyranosyl)-β- d-glucopyranose (hexabenzyl-1,6-anhydrocellobiose) leads to products of number average molecular weights of 6–7 x 10 3 and specific rotations as high as +80° ( c 1, chloroform). Variations in reaction conditions affect the molecular weight and optical rotation of products significantly. Conditions giving maximum stereoregularity and molecular weight are similar to those observed with the corresponding maltose derivative. Debenzylation of products yielded nondialyzable hydrated oligosaccharides, presumably comb-shaped, of [α] ▪ + 77.8° ( c 1, water; observed) or [α] ▪ + 84.3° ( c 1, water; calculated for anhydrous weight). Analysis of the oligosaccharide, like the products from the corresponding maltose derivative, indicates the presence of 1.5 molecule of water for each repeating disaccharide unit. Presumptive evidence suggests that the products of highest optical rotation are highly stereoregular.

The preparation of comb-shaped polysaccharides by polymerization of a maltose derivative

The Lewis acid-catalyzed polymerization of 1,6-anhydro-2,3-di- O-benzyl-4- O-(2,3,4,6-tetra- O-benzyl-α- D-glucopyranosyl)-β- D-glucopyranose (1,6-anhydromaltosehexabenzyl ether) leads to products of number-average molecular weights up to about 14,000 and specific rotations as high as +96–97°. Variations in reaction conditions affect the molecular weight and optical rotation of the products significantly. Debenzylation of the products having the highest molecular weight and optical rotation yields hydrated polysaccharides, presumably comb-shaped, of [α] 25 D + 174° (or corrected to a water free condition [α] 25 D + 189°). This value corresponds to a high degree of stereoregularity in the main chain with predominantly α- D linkages on both the main chain and branches.

The determination of the configuration of the glycosidic link in oligosaccharides by p.m.r. spectroscopy of trimethylsilyl derivatives

The essential points of the p.m.r. spectra of the trimethylsilyl derivatives of maltose, cellobiose, α,α-trehalose, lactose, sucrose, lactulose, raffinose and melezitose are given. The protons on the anomeric carbon atoms resonate at lower field than the remaining protons. On the basis of this feature a new method for the determination of the configuration of the glycosidic link in oligosaccharides has been developed.

Acid-catalyzed hydrolysis of maltose derivatives containing nitrogen

Acid-catalyzed hydrolysis of maltose derivatives containing nitrogen

The Reaction of Ammonia with Acylated Disaccharides. VIII. Octa-O-benzoylmaltose and Benzoyl Derivatives of Maltose

The Reaction of Ammonia with Acylated Disaccharides. VIII. Octa-O-benzoylmaltose and Benzoyl Derivatives of Maltose

SYNTHESIS OF 6′-SUBSTITUTED MALTOSES

Derivatives of maltose substituted at position 6′ have been prepared by the replacement of a 6′-O-p-toluenesulfonate ester by various reagents. Tritylation of 1,6-anhydro-β-maltose followed by acetylation and detritylation yielded 2,3,2′,3′,4′-penta-O-acetyl-1,6-anhydro-β-maltose, which gave the 6′-O-p-toluenesulfonate in good yield. Replacement of the sulfonate ester with iodide led to a derivative from which 6′-deoxy-maltose was prepared by reduction, acetolysis, and deacetylation. 6′-Deoxy-6′-mercapto-maltose was prepared by replacement of the sulfonate with thiolacetate followed by acetolysis and deacetylation. 6′-Amino-6′-deoxy-maltose was prepared in low yield by azide replacement of the sulfonate, deacetylation, reduction, and mild acid hydrolysis.Attempts to prepare 6-substituted derivatives from benzyl 4′,6'-O-benzylidene-β-maltoside were unsuccessful. The possible explanations for the unreactivity of position 6 are discussed.

Acid-catalyzed hydrolysis of maltose and selected maltose derivatives

Acid-catalyzed hydrolysis of maltitol, maltose phenylosotriazole, maltose cyanohydrin, and maltobionic acid differ very little from that of the parent compound, maltose, as determined by energies (30–33 kcal.mole -1) and entropies (+6 to 15 cal.mole -1degree -1) of activation. The hydrolysis of maltose I-phenyl-flavazole, however, had a much lower molar activation energy (13.2 kcal.mole -1) and a much more negative entropy of activation (—46.7 cal.mole -1degree -1). It is suggested that these differences are indicative of a different reaction mechanism for the hydrolysis of the latter compound.

The Reaction of Ammonia with Acylated Disaccharides. III. Acetyl Derivatives of Maltose and an Interpretation

The Reaction of Ammonia with Acylated Disaccharides. III. Acetyl Derivatives of Maltose and an Interpretation

Substrate Specificity and Some Properties of Crystalline Mold Maltase

The substrate specificity of crystalline mold maltase was investigated.The enzyme acts upon various α-heteroglucosides or saccharides. Aryl-α-glucosides were hydrolyzed much faster than alkyl-α-glucosides. The enzyme acts on the maltose derivatives whose reducing groups have been masked. But among glucosylfructoses turanose, maltulose and isomaltulose were attacked with a slow rate while the enzyme was quite inert to sucrose. Malto- and isomalto-oligosaccharides were also hydrolyzed and the enzyme ceased its action at seven to eight units of hexose in both series of oligosaccharides.The opt. pH range of Takamaltase was 4.2~4.6 and opt. temp., 50~55°C. Cu++ and Hg++ strongly inhibited the enzyme activity but other metal ions tested had no effects. It is suggested that the enzyme is not a sulfhydryl enzyme because of the lack of effects of SH-reagents on the activity.

Substrate Specificity and Some Properties of Crystalline Mold Maltase

The substrate specificity of crystalline mold maltase was investigated. The enzyme acts upon various α-heteroglucosides or saccharides. Aryl-α-glucosides were hydrolyzed much faster than alkyl-α-glucosides. The enzyme acts on the maltose derivatives whose reducing groups have been masked. But among glucosylfructoses turanose, maltulose and isomaltulose were attacked with a slow rate while the enzyme was quite inert to sucrose. Malto- and isomalto-oligosaccharides were also hydrolyzed and the enzyme ceased its action at seven to eight units of hexose in both series of oligosaccharides. The opt. pH range of Takamaltase was 4.2~4.6 and opt. temp., 50~55°C. Cu++ and Hg++ strongly inhibited the enzyme activity but other metal ions tested had no effects. It is suggested that the enzyme is not a sulfhydryl enzyme because of the lack of effects of SH-reagents on the activity.

Methanol-Soluble Complexes of Lactose and of Other Carbohydrates

Summary Lactose, sucrose, maltose, galactose, fructose, and many other carbohydrates and derivatives are found highly soluble in cold absolute methanol containing sufficient calcium chloride. From a highly concentrated viscous solution prepared from lactose, calcium chloride, and methanol in a molar ratio such as 1:3:24, a complex of β -lactose, calcium chloride, and methanol in the molar ratio of 1:1:4 slowly crystallizes. After about 6 M of water are added to such a concentrated solution per mole of calcium chloride, a complex of α -lactose, calcium chloride, and water in the molar ratio 1:1:7 soon crystallizes. The equilibrium ratio of α - to β -lactose in the concentrated solutions is about 5:3. The dilution of such a concentrated solution with methanol causes lactose to crystallize in the same anomeric ratio as exists in the solution. Within the investigated range, the logarithm of the solubility of this crystallized lactose in methanol is a linear function of the calcium chloride concentration.

The Configuration and the Mechanism of Hydrolysis of the Maltose Derivatives with Orthoester Structure

The Configuration and the Mechanism of Hydrolysis of the Maltose Derivatives with Orthoester Structure

OPTICAL ROTATION AND ATOMIC DIMENSION. VIII. HALOGENO-HEPTA-ACETYL DERIVATIVES OF MELIBIOSE AND MALTOSE. THE STRUCTURES OF BIOSES AND CELLULOSE

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOPTICAL ROTATION AND ATOMIC DIMENSION. VIII. HALOGENO-HEPTA-ACETYL DERIVATIVES OF MELIBIOSE AND MALTOSE. THE STRUCTURES OF BIOSES AND CELLULOSED. H. BraunsCite this: J. Am. Chem. Soc. 1929, 51, 6, 1820–1831Publication Date (Print):June 1, 1929Publication History Published online1 May 2002Published inissue 1 June 1929https://doi.org/10.1021/ja01381a032RIGHTS & PERMISSIONSArticle Views141Altmetric-Citations52LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts