Of glucopyranose

Barrows S E, J W Storer, C J Cramer, A D French and D G Truhlar 1998. Factors Controlli Relative Stability of Anomers and Hydroxymethyl Conformers of Glucopyranose. Journal Computational Chemistry 19 1111-1129. 

An important characterization parameter for ceUulose ethers, in addition to the chemical nature of the substituent, is the extent of substitution. As the Haworth representation of the ceUulose polymer shows, it is a linear, unbranched polysaccharide composed of glucopyranose (anhydroglucose) monosaccharide units linked through thek 1,4 positions by the P anomeric configuration. 

Fig. 2. Geometries calculated (solid lines) and observed (bold dashed lines) for 1-propanol in its a-cyclodextrin adduct. G3 and G6 denote the numbers of glucopyranose units of a-cyclodextrin. H3 and H5 refer to the hydrogen atoms located inside of the cyclodextrin cavity. The hydrogen atoms for the observed geometry of 1-propanol are not shown, since their atomic coordinates have not been determined. The observed 1-propanol is twofold disordered, with site a occupied 80%, site b 20%. Interatomic distances are shown in bold italics on fine dashed lines (nm). Reproduced with permission from the Chemical Society of Japan...

The three most used cyclodextrins are known as a, [3, and y, and these contain six, seven, and eight units of glucopyranose, respectively. The structure of the cyclodextrins is in the shape of a truncated cone, the cavity of which has... 

Figure 9.16 Structures of glucopyranose homopolysaccharides. Cellulose is a linear structure of the glucopyranose units linked /3( 1 —>4). Starch consists of amylose, which has a linear < (1—>4) structure, and amylopectin, which has a(l—>6) branch points on the linear a(l—>4) chains. Glycogen has a similar structure to amylopectin, but with a greater degree of < ( 1—>6) branching.

Modeling of Glucopyranose The Flexible Monomer of Amylose Alfred D. French, R. S. Rovdand and Norman L. Allingei ... 

Cellulose is reputedly the most abundant organic material on Earth, being the main constituent in plant cell walls. It is composed of glucopyranose units linked pi 4 in a linear chain. Alternate residues are rotated in the structure, allowing hydrogen bonding between adjacent molecules, and construction of the strong fibres characteristic of cellulose, as for example in cotton. 

Starch consists of two main components amylose (insoluble in cold water) and amylopectin (soluble in cold water). Amylose, which accounts for about 20 per cent by weight of starch, has an average molecular weight of over 10. It is a polymer of glucopyranose units linked together through a l,4 -linkages in a linear chain. Hydrolysis of amylose produces maltose. Amylose and iodine form a colour complex, which is blue/black. This is the colour reaction of iodine in starch, a confirmatory test for the presence of starch. 

Tanaka, T., Nonaka, G., Ishimatsu, M., Nishioka, I., and Kouno, I., 2001, Revised structure of cercidinin A, a novel ellagitannin having (R)-hexahydroxydiphenoyl esters at the 3,4-positions of glucopyranose, Chem. Pharm. Bull. 49 486-487. 

The product of this reaction is a hemiacetal that contains a six-membered ring known as a pyranose. Two isomers of glucopyranose can be formed, depending on whether the OH group attacks from above or below the C=0 group. 

To a mixture of glucopyranose (0.22 mmol) in dry cyclohexane (24 ml) under an argon atmosphere were added iodosylbenzene (0.43 mmol) and iodine (0.22 mmol) at room temperature. The mixture was stirred for 20 h at the same temperature. After the reaction, the reaction mixture was poured into water and extracted with ether. The organic layer was washed with aq. sodium thiosulfate solution, water, and dried over Na2S04. After removal of the solvent, the residue was chromatographed on silica gel (eluent hexane/ethyl acetate = 65/35) to give D-arabinose derivative in 86% yield [68]. 

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