Takashi Kuge

Complexes of Starchy Materials with Organic Compounds

Complexes of amylose with several kinds of n-aliphatic ketones having different chain lengths, different positions and numbers of carbonyl groups in the molecules were prepared. The unit cell dimensions of the complexes were calculated in both the wet and dried states by means of X-ray diffraction analysis. Both the 61- and 71-helix amyloses were presented in these complexes. It was found that the helix packing diameter of the amylose-ketone complex changes depending upon the linear chain length of the ketone molecule complexed.

Synthesis of methyl α- and β-maltotriosides and aryl β-maltotriosides

Abstract Reaction of β-maltotriose hendecaacetate with phosphorus pentachloride gave 2′,2″,3,3′,3″,4″,6,6′,6″,-nona- O -acetyl-(2)- O -trichloroacetyl-β-maltotriosyl chloride (2) which was isomerized into the corresponding α anomer (8) . Selective ammonolysis of 2 and 8 afforded the 2-hydroxy derivatives 3 and 9 , respectively; 3 was isomerized into the α anomer 9 . Methanolysis of 2 and 3 in the presence of pyridine and silver nitrate and subsequent deacetylation gave methyl α-maltotrioside. Likewise, methanolysis and O -deacetylation of 9 gave methyl β-maltotrioside which was identical with the compound prepared by the Koenigs—Knorr reaction of 2,2′,2″,3,3′,3″,4″,6,6′,6″-deca- O -acetyl-α-maltotriosyl bromide (12) with methanol followed by O -deacetylation. Several substituted phenyl β-glycosides of maltotriose were also obtained by condensation of phenols with 12 in an alkaline medium. Alkaline degradation of the o -chlorophenyl β-glycoside decaacetate readily gave a high yield of 1,6-anhydro-β-maltotriose.

Study on the retrogradation of starch. I. Particle size and its distribution of amylose retrograded from aqueous solutions

Abstract The morphological features of amylose precipitates, especially the particle size and size distribution, during retrogradation have been investigated using scanning electron microscopy. It was found that the retrograded amyloses consisted of particles with a surprising uniformity in size, and the volume of each particle increased proportionally with the degree of retrogradation. These facts suggest that the retrogradation of amylose proceeds via a nucleation process, which is complete within a short time after the onset of retrogradation; this is then followed by growth of the nuclei. It was also found that, at a given percentage of retrogradation, the particle volume increased with increasing concentration of KCl in the solution. It was, therefore, considered that the reduction in the rate of retrogradation induced by KCl may be attributed to a decrease in the number of nuclei produced in the initial stage.

Synthesis of cellobiose, cellotriose, cellotetraose, and lactose

Abstract Condensation of 2,3,4,6-tetra- O -acetyl-α- d -glucopyranosyl bromide ( 1 ) with benzyl 2,3,6-tri- O -benzyl-β- d -glucopyranoside ( 6 ) in 1:1 benzene—nitromethane in the presence of mercuric cyanide gave, in 86% yield after O -deacetylation followed by column chromatography, benzyl 2,3,6-tri- O -benzyl-β-cellobioside, which was catalytically hydrogenolyzed to afford cellobiose. In a similar way, methyl α-cellobioside, cellotriose, methyl α- and β-cellotriosides, cellotetraose, lactose, and methyl α-lactoside were synthesized with high stereospecificity and in good yield by the coupling reaction, using methyl 2,3,6-tri- O -benzyl-α- and -β- d -glucopyranoside, 6 , and benzyl 2,3,6,2′,3′,6′-hexa- O -benzyl-β-cellobioside as the glycosyl acceptors, and 1 , 2,3,4,6-tetra- O -acetyl-α- d -galactopyranosyl bromide, and hepta- O -acetyl-α-cellobiosyl bromide as the glycosyl donors.

Chemical modification of the nonreducing, terminal group of maltotriose☆

Abstract O -α- d -Galactopyranosyl-(1→4)- O -α- d -glucopyranosyl-(1→4)- d -glucopyranose (12) was prepared by inversion of configuration at C-4″ of 2,3,2′,3′,6′,2″,3″-hepta- O -acetyl-1,6-anhydro-4″,6″-di- O -methylsulfonyl-β-maltotriose (7) , followed by O -deacylation, acetylation, acetolysis, and de- O -acetylation. The intermediate 7 was obtained by treatment of 1,6-anhydro-β-maltotriose (2) with benzal chloride in pyridine, followed by acetylation, removal of the benzylidene group, and methane-sulfonylation. Selective tritylation of 2 and subsequent acetylation afforded 2,3,2′,3′,6′,2″,3″,4″-octa- O -acetyl-1,6-anhydro-6″- O -trityl-β-maltotriose (6) , which was O -detritylated and p -toluenesulfonylated to give 2,3,2′,3′,6′,2″,3″,4″-octa- O -acetyl-1,6-anhydro-6″- O - p -tolylsulfonyl-β-maltotriose (13) . Nucleophilic displacement of 13 with thioacetate, iodide, bromide, chloride, and azide ions gave 6″- S -acetyl- (14) , 6″-iodo- (15) , 6″-bromo- (16) , 6″-chloro- (19) , and 6″-azido- (20) 1,6-anhydro-β-maltotriose octaacetates, respectively. 6″Deoxy- (18) and 6″-acetamido-6″-deoxy (21) derivatives of 1,6-anhydro-β-maltotriose decaacetates were also prepared from 15 and 16 , and 20 , respectively. Acetolysis of 14 , 15 , 16 , 18 , 19 , and 21 afforded 1,2,3,6,2′,3′,6′,2″,3″,4″-deca- O -acetyl-6″- S -acetyl (22) , -6″-iodo (23) , -6″-bromo (24) , -6″-deoxy (25) , -6″-chloro (26) , and -6″-acetamido-6′-deoxy (27) derivatives of α-maltotriose, respectively. O -Deacetylation of 24, 25 , and 26 furnished 6″-bromo- (28) , 6″-deoxy- (29) , and 6″-chloro- (30) maltotrioses, respectively, which on acetylation gave the corresponding β-decaacetates.

Complexes of Starchy Materials with Organic Compounds:Part II. Complex Formation in Aqueous Solution and Fractionation of Starch by l -Menthone

More than one hundred organic compounds have been examined with respect to their precipitation abilities for starch. All the precipitates may be caused subsequent to complex formation between amylose and reagents. A slight change in molecular structure of the reagent often results in a marked change of the complex formation. The complicated nature of the complex formation is discussed. Some of naturally ocurring monoterpenes, especially l-menthone, showed superior properties as selective precipitants for amylose. So the fractionation of starch was attempted using l-menthone and a good result was obtained.

Complexes of starchy materials with organic compounds part III. X-ray studies on amylose and cyclodextrin complexes

X-Ray analyses of the complexes of amylose with various organic compounds were carried out. Only two kinds of diffraction patterns were observed in the dried state. The first one corresponds to the helix of amylose consisting of six glucose residues per helical turn (61-helix) and the second to that consisting of seven glucose residues (71-helix). The 71-helix was obtained with a relatively wide range of the size of the complexing agents, 4.5~6.0 A in diameter of cross section. Mutual transitions between both helices were made possible by displacing the contained agent with one of the other kinds. During the transition courses, the helix with a fractional number of glucose residues could not be seen. It is, hence, infered that the helix is stabilized by hydrogen bonds between individual helical loops. The diffraction patterns of cyclodextrin complexes were also examined. Under suitable conditions α- and β-dextrins can produce complexes having analogous crystalline structures of 61-helix and 71-helix amylo...

Conformation and physical properties of amylose in aqueous solutions

Abstract This review describes the progress of recent studies on the conformation and the physical properties of amylose in aqueous solutions. In the first three sections the conformation of amylose in solution is discussed in terms of the results obtained by hydrodynamic studies, computer simulations and fluorescence depolarization measurements. The following sections include two examples of the physical properties of amylose in aqueous solutions: the complex formation with a fluorescent dye and the retrogradation.

Complexes of Starchy Materials with Organic Compounds:Part IV X-Ray Diffraction of γ-Cyclodextrin Complexes

The crystal structure of γ-cyclodextrin complexes with several organic compounds have been investigated by X-ray powder method. A two-dimensional tetragonal unit cell having a=b=27.2 A and a two-di...

Study of Polysaccharides by the Fluorescence Method. V. Interaction of 2-p-Toluidinylnaphthalene-6-sulfonate with Amylose and its Related Compounds in Aqueous Solution

The interaction of 2-p-toluidinylnaphthalene-6-sulfonate (TNS) with amylose and its related compounds in aqueous solution has been studied by both steady-state and transient fluorescence measurements. The fluorescence of TNS aqueous solution was enhanced by the addition of amylose, β-limit dextrin, and amylopectin. The fluorescence decay of TNS bound to these polysaccharides were well described as a sum of two-exponential functions. This suggests that there are two different microenvironments at the binding sites. The fluorescence lifetime of major component for TNS-amylose system agreed with that of major component for TNS-γ-cyclodextrin system. The mean rotational relaxation time of TNS bound to amylose is similar to that of the segmental motion of amylose chain. Based on these results, a configurational model for TNS-amylose complex has been proposed.